Section II

Case Study 12

Poison Prevention and Education

INTRODUCTION

Unintentional poisonings are a global health concern. According to the World Health Organization (WHO) Global Burden of Disease Project, in 2004 approximately 3,346,000 people died worldwide from unintentional poisoning.⁸⁰ Nearly 1 million people die each year as a result of suicide. Approximately 350,000 deaths result from the deliberate ingestion of pesticides. In addition, an estimated 5 million snakebites occur annually.⁸⁰ The WHO has undertaken initiatives in many countries, including the Bahamas, China, Ghana, Lebanon, Myanmar, Senegal, and Trinidad and Tobago to establish Poison Centers (PCs) and raise awareness about poison prevention. Worldwide, data on nonfatal poisoning rates are currently not available, although the increase in poison centers globally may result in improved research and surveillance programs.⁵⁴ This chapter focuses on programs in North America that aim to prevent unintentional poisonings and improve access to PC services.

Healthy People 2020 is a US federal program that outlines the health goals for the nation. These overarching goals are to attain high quality longer lives, achieve health equality and eliminate disparities, create social and physical environments that promote good health and promote quality of life, healthy development, and healthy behavior across all life stages. Two objectives in the Injury and Violence Prevention section relate to poison prevention. Objective IVP-9 is to reduce poisoning deaths and Objective IVP-10 is to reduce nonfatal poisonings.²⁵ Community based public education programs at PCs are designed to help meet these other public health objectives.

LEGISLATION AND POISON PREVENTION

Since the first PC was established in 1953, a number of legislative efforts have improved poison prevention and awareness and reduced the number of unintentional poisonings in children. Public education programs at PCs have been influenced by these federal measures.⁷¹

National Poison Prevention Week

In 1961, President Kennedy signed Public Law 87–319, designating the third full week of March as National Poison Prevention Week (PPW) to raise awareness of the dangers of unintentional poisonings. Each year, ­during PPW, PCs and other organizations around the country organize events and activities to promote poison prevention.

Child-Resistant Packaging Act

In 1970, the Poison Prevention Packaging Act was passed. This law requires that the Consumer Product Safety Commission (CPSC) mandate the use of child-resistant containers for toxic household xenobiotics. In 1974, oral prescription medications were included in this requirement. A review of mortality data in children younger than 5 years of age shows a significant decrease in deaths after enforcement of the child-resistant packaging legislation.^61,71,75

Taste-Aversive Xenobiotics and Poison Prevention

Nontoxic taste-aversive xenobiotics are frequently added to products such as shampoo, cosmetics, cleaning products, automotive products, and rubbing alcohol to discourage ingestion.²⁴ This is done primarily to prevent poisoning in children except in the case of rubbing alcohol, where adults are also targeted. The most common taste-aversive xenobiotics are the denatonium salts, particularly denatonium benzoate (Bitrex, benzyldiethyl [(2,6-xylylcarbamoyl)methyl] ammonium benzoate), one of the most ­bitter-tasting xenobiotics known. The bitter taste of denatonium benzoate can be detected at 50 parts per billion (ppb). This aversive xenobiotic is used in concentrations of 6 to 50 parts per million (ppm), typically 6 ppm in cosmetic products and ethanol-containing household products and 30 to 50 ppm in methanol and ethylene glycol.^8,53 Only limited data are available on the usefulness of taste-aversive xenobiotics for prevention of poisoning. Studies using denatonium benzoate added to liquid detergent and orange juice demonstrate that it can decrease the amount ingested by children.^6,67 However, the degree of taste aversion is not universal. In one study, some children were noted to take more than one sip of denatonium benzoate-containing orange juice.⁶⁷ Taste aversion is partially a learned response. Frequently young children do not find a bitter taste as offensive as do adults.⁷ It seems unlikely that taste-aversive xenobiotics will eliminate unintentional ingestions in children, because ingestion is required for aversive effects to occur. Taste-aversive xenobiotics may be most beneficial in the prevention of poisoning by toxic and nonaversive xenobiotics, such as ethylene glycol, methanol, paraquat, certain pesticides, acetonitrile, and bromate-containing cosmetics, where more than one or two sips of the product must be ingested to cause significant toxicity. In 1995, Oregon became the first state to mandate the addition of an aversive xenobiotic to ethylene glycol- or methanol-containing car products in its 1995 Toxic Household Products statute. Analysis on the incidence and severity of ethylene glycol and methanol exposures before and after the mandate could not demonstrate any difference in children under 6 years of age.⁴⁹ Taste-aversive xenobiotics should therefore not be substitutes for other poison prevention modalities.

Toll-Free Access to Poison Centers

In 2000, the Poison Control Center Enhancement and Awareness Act (PL 106-174) was enacted with a goal of nationwide access to PCs. A toll-free number (1-800-222-1222) was established in 2001 for all US PCs.⁷⁸­Callers are connected to a regional PC based on the area code and telephone number exchange. Figure 135–1 displays the national logo incorporated into educational efforts.

ROLE OF PUBLIC EDUCATORS IN POISON CENTERS

Poison Center educators encompass a range of educational backgrounds including nurses, pharmacists, health educators, and teachers. The role of the public educator is based on social marketing concepts and encompasses two objectives: health promotion to change behavior, and marketing of the PC.⁶⁹ Public education programs at PCs teach poison prevention techniques (primary prevention) and raise awareness about available services should a poisoning occur (secondary prevention). Education programs may utilize primary or secondary teaching or a combination of both.^5,27,32,39 Public educators at PCs provide a range of community based programs ranging from workshops and health fairs to producing print materials, videos and or DVDs, and awareness campaigns through public service advertising using radio, television, print, and mass transit venues. Social media in health promotion offers an opportunity to further expand the dissemination of health information to diverse audiences through enhanced communication.⁴⁷ Since underserved groups use mobile handheld devices frequently to access information,cell phones, mobile technology, and online resources provide new ways that educators can disseminate health messages to those in need.

Educators also participate in community health coalitions, working in conjunction with other injury prevention groups such as National Safe Kids, and collaborate with a wide range of community health agencies. Caregivers of children younger than age 6 have often been the most important group to reach with education programs. Educators often work with national programs for families including Women, Infant and Children (WIC), Head Start, and the Red Cross.

By contrast, older adults (individuals older than 65 years of age) have not been a priority population for PC education resources. However, this group represents a large number of fatalities reported nationally to PCs, primarily due to medication errors.^10,27 Programs for older adults offer an educational opportunity to reach this high risk population. Collaborative programs with the American Association of Retired Persons (AARP), senior centers, and Departments for the Aging offer an opportunity to provide collaborations focusing on poison prevention and medicine safety programs through educational interventions conducted in senior centers, community agencies, and other groups that serve independently living older adults.

The membership of the American Association of Poison Control ­Center’s Public Education Committee (PEC) includes the educators from PCs across the United States and Canada. The mission of the PEC is to provide poison prevention awareness programs in an effort to reduce ­morbidity and mortality associated with poisoning. Each year, the PEC provides educational sessions at the North American Congress of Clinical Toxicology. PEC workshops focus on program development, evaluation, grant writing, strategic planning, and other topics of interest to PC educators.²⁷

NEEDS ASSESSMENTS

To develop successful poison education programs, educators must first analyze demographic data, call volume rates, cultural and language issues, and barriers to calling a PC. Geographic information systems (GIS) software offers a way for PCs to map demographic data. The use of this type of software is increasing in public health and can be applied to PC efforts. The coordination of data retrieval from various data entry programs and the use of GIS software by PC staff provides access to call rates by zip codes, counties, census tracts, or congressional districts to be used for planning programs. Health and social services for the targeted community may also be presented using GIS maps. Using GIS for population based programs is recommended for developing social marketing campaigns, health education programs, outreach efforts, and coalition building.⁶⁰ The study of geographic areas with low call rates enhances the potential for targeted and focused educational programs.

Focus groups, surveys, and interviews provide useful qualitative methods for PC educators to identify the perceptions of parents and caregivers about calling the PC. Barriers regarding PC utilization include not knowing the PC number, preference for calling 9-1-1 rather than the PC, fear of being reported to child welfare agencies, concerns with regard to confidentiality, language difficulties, lack of in person contact with health care providers, low self-efficacy, and concerns regarding the cost of the call.^{1,4,9,28,29,65,73} Each of these barriers must be considered and creatively addressed when planning new programs for reaching caregivers of young children. In one study, 51% of caregivers interviewed in a low income urban pediatric clinic said that they would immediately take their children to the emergency department (ED) after a possible poisoning exposure.⁶³ In a separate study, focus group participants stated they would not call the PC in the case of a poison emergency. Their responses ranking was (1) call the pediatrician, (2) go to the ED, (3) read the label, and (4) call a friend after a poisoning exposure.²⁸ A focus group with parents provided information to refine a telephone survey concentrating on hazardous household materials and health risks. Feedback from caregivers resulted in a more concise instrument with more targeted questions. In addition, perceptions of the PC and suggestions for future educational interventions were also gathered from participants.²⁸ Involving the target audience in the development and testing of information is demonstrated to have improved outcomes when disseminating information.⁷²

Follow-up surveys provide a way to analyze factors related to PC access. English- and Spanish-speaking caregivers in Texas were contacted after an ED visit related to a poisoning exposure in a child. Findings showed that more than half had spoken to PC staff prior to the hospital visit. Of those who did not call the PC, 68% claimed prior knowledge of the PC, yet failed to use it. Significant demographic variables associated with a failure to call the PC were Hispanic (schooled in Mexico) and African American ethnicities.³¹ Findings from an ethnographic study of 50 Mexican-American mothers with children younger than 5 years of age demonstrated that none had the PC number in their home.⁴⁶

In person interviews were conducted with parents in the pediatric clinic about poison prevention strategies and awareness of the poison center.^16,20 A pilot study to determine predictors of storage included accultur­ation, age, gender, and education among parents found that less acculturated parents were more likely to store medicines and cleaning products unsafely in the home.¹⁶ Another study conducted with 216 parents and ­caregivers reported that 80% were aware of the poison center services. However, none knew the 800 number specifically, although many stated they had the number in their home. Of the 42 participants (20% of the sample) unaware of the PC services, 57% were non-English speakers.²⁰

In order for educators to plan effective programs with older adults a needs assessment of the perceived barriers and benefits for this target group related to accessing the PC is required. Focus groups conducted with older adults show that most do not perceive the PC as an appropriate service for their concerns, but rather as a service for children and parents. Additionally, the participants expressed a very narrow view of what was considered a poison such as bleach and household products. Similar to caregivers of children, older adults repeatedly state that they would call 9-1-1 in an emergency.¹¹

POISON EDUCATION PROGRAMS

Over half of the 2 million annual calls to PCs nationally involve children younger than 6 years of age.¹⁰ As a result, programs to teach caregivers about primary and secondary prevention techniques have been the major aim of education efforts. Typically, these programs focus on teaching poison prevention (Table 135–1) and raising awareness of PC services. Poison education programs designed to address barriers to accessing the PC through community interventions are reported in the literature. In one study, parents at two WIC centers reported an increased comfort level with calling the PC after a video based intervention.³⁰ Interventions have demonstrated an increase in knowledge about PC messages and poison prevention in the study groups.^30,38

Interventions Targeting Health Behavior

Unintentional poisonings frequently happen when children are left unattended for a brief period of time (< 5 minutes) and a toxic product in use or recently purchased is left within reach of the unattended child.⁵¹ A qualitative study conducted of 65 parents, some whose children had experienced an unintentional poisoning, showed that poison prevention strategies were not consistently implemented in the home. Recommendations included ongoing parent education to reemphasize that “child resistant” is not “childproof,” and reinforce safe storage of potentially toxic products, particularly those that are often used.²² When knowledge and behavior were measured through telephone surveys conducted 3 months after a poison prevention packet was mailed to families of young children who had experienced a poisoning, caregivers were more likely to have the PC number posted in the home.^30,79

The ED presents an opportunity for poison education programs to work with families to prevent further poisoning exposures.¹⁷ An injury prevention program provided to caregivers of young children after a home injury was effective, particularly regarding retention of poison prevention information and the use of safety devices.⁵⁶ The use of a computer kiosk in an ED to provide personalized child safety information including specific advice of poison storage for parents showed increased knowledge scores on follow-up telephone surveys.²³

The effectiveness of poison prevention education for families who called the PC following a potential exposure in a young child was also studied. Poison prevention instructions, telephone stickers, and a cabinet lock were sent to the family one week after the initial call. Follow-up telephone interviews showed that intervention group recipients reported a higher use of the cabinet lock (59%) and were significantly more likely to post the telephone number for the PC (78%) than those in the control group who did not receive any poison prevention materials within 2 weeks of the incident.⁷⁹

Poison education programs developed to address caregiver barriers have also been evaluated. An educational video targeting low income and Spanish speaking mothers was developed and evaluated. Results showed increased knowledge about the services, staff, and appropriate use of the PC compared with a control group that attended the regularly scheduled WIC class.³⁰

Instructor training programs have been designed by a number of PCs to reach leaders or educators of community based organizations to incorporate poison education into their roles for the general population. An evaluation of the “Be Poison Smart” program showed an increase in knowledge and behavior change among service providers after a standardized training session. These reported changes included having the PC number visibly posted and keeping hazardous products out of reach.⁵⁵ Working with community based services such as WIC presents an opportunity to reach the target population. Pretests and posttests administered to WIC staff and public health nurses showed increased understanding about poison prevention and increased awareness of PC services.⁵⁷ Community health workers (promotoras) are involved in health promotion particularly in hard to reach communities. A train-the-trainer model evaluation demonstrated increased knowledge and behavior for teaching healthy homes promotion in the community setting.⁴⁰

Focus group participants identified pediatricians as a trusted source of health information for parents.^28,65 The AAP includes a poison prevention counseling recommendation as part of The Injury Prevention Program (TIPP). TIPP is a safety education program for parents of children newborn through 12 years of age. The TIPP age related safety sheets include poison prevention advice for parents of children aged 6 to 12 month, 1 to 2 years, and 2 to 4 years.² Each safety sheet encourages parents to call the toll-free number for PCs if the child ingests a potentially poisonous product. It is important that the AAP continues its support for efforts by PCs to prevent childhood poisonings.³⁹ In another study, family practitioners and pediatricians were surveyed with respect to poison prevention counseling for parents. Although more than 80% of both groups reported that this was an important topic, family practitioners were less likely than pediatricians to provide poison information during a visit.²¹

Education programs are designed for school-age curricula. The effectiveness of MORE HEALTH, a program to teach kindergarten and third-grade students about poison prevention, was studied.³⁸ Posttests administered 1 to 2 weeks after the intervention showed increased knowledge in the intervention group of children. Parents of children in the intervention group also self reported that their homes were more likely to be “poison-proofed.”

Recommendations have been made to develop programs targeting older adults, particularly about potential problems with medication use and storage.^27,36,68 Efforts to teach nursing home staff about potential poisoning exposures are also recommended.³⁶ There has been a shift in the priority of poison education programs to address this target population. An ED study of older adults showed that seniors had poor knowledge of their current medications. In addition, patients taking more medications were less likely to know the proper dose, name, and purpose of the medications.^14,76

Community-Wide Interventions

A review of pediatric literature focusing on community based poisoning prevention programs showed that only four studies could be found using poisoning rates as the outcome measure. Additional creative studies to measure community based poison prevention efforts will be essential to determine the importance of these efforts.⁵⁰

In general, mass mailing of poison information is generally not an effective means to increase call volume for poison exposure or information requests nor is it cost effective.^19,34 Similarly, a distribution of textbook covers with the national logo and PC information to elementary and secondary schools in low PC utilization counties was not an effective method for increasing PC calls.⁸² A hospital mailing that combined primary (poison prevention tips) and secondary (telephone stickers) messages were included in an established family health promotion magazine distributed widely in the PC regional area. This effort resulted in an increased call volume in areas where at least 5% of the residents received the information.³² In addition, another study result in that overall call volume increased by 11.2% after more than 1 million pieces of literature containing the toll-free number were distributed at sites including emergency departments, doctor offices, schools, and pharmacies.³³

An increased number of information calls to the PC was attributed to a campaign developed to raise community awareness.⁷⁰ Media provide a venue for conducting educational activities. Direct mail, radio, television, newspapers, and magazines were incorporated into a media campaign developed to raise awareness in a particular Latino community. A telephone survey conducted pre- and post-media campaign showed an increase in awareness about the PC.¹ Although developing this type of program is often costly compared with other education efforts, the potential audiences are vast. Mass media campaigns are powerful tools used in health promotion and disease prevention efforts.⁵⁸ Research shows that a multilevel approach of media campaigns combined with community-based interventions and health education materials influence health behaviors and raise awareness. Additional factors that contribute to ­successful mass media campaigns include influencing the information environment to maximize exposure, using social marketing strategies, creating a supportive environment for the target audience to make health changes, and theory based process analyses to permit changes ­mid-campaign and assess outcomes and subsequent strategies in an iterative manner.⁵⁸ Radio and television news stations often provide a way to broadcast poison prevention messages during PPW and during periods associated with perceived increased risks to a community. Social media is viewed as a communications tool rather than a factor in behavior change. Therefore, a process evaluation strategy is appropriate for ­measuring reach, context, delivery, and fidelity of application.⁴⁷

Multilingual Populations

Language and culture must be addressed when planning community-based programs. Quantitative and qualitative research examining Latino communities and calls to the PC have been conducted. The findings from interviews with 206 Latino parents at a WIC site showed that 62% had not heard of the local PC and 77% did not know the PC services were free and offered in Spanish.⁷⁴ Two other studies examined the call rates in communities with significant Latino populations. These areas had lower call rates than comparable areas based on demographic and socioeconomic factors.^15,73 Furthermore, a number of studies demonstrate that Spanish speaking caregivers are less likely to call the PC because of concerns including confidentiality and language barriers.^1,4,15,29,46 In a study conducted with 100 Mexican-American mothers of children younger than 5 years of age, 32% reported that a doctor or nurse would be the initial contact for health advice.⁴³ Other sources include friends and family (29%), mother, grandmother, mother-in-law (21%), and spouses (17%). Most of the mothers (81%) acknowledged the use of home remedies to treat their childrens’ illnesses.⁴³ New immigrant families from Mexico and Latin America are at high risk for poisoning exposures. PC education programs should target populations in communities where the impact has the potential to be consequential.⁶⁶ Caution should be used when planning programs based on census data for demographic information as this data may not reflect the specific population or characteristic under study in community based programs. When ethnicity information is not collected from callers who contact the PC, there are severe limitations to the value of the data.¹⁵

Qualitative research can help to identify cultural issues when planning targeted education efforts. Monolingual Spanish speaking mothers were more likely to report poor storage of household products and lack of protective placement of plants.¹ Mexican-born mothers of children younger than 5 years of age were interviewed in their homes about poison prevention techniques. Safe storage was clearly a problem in these homes with 64% of homes having bleach stored within reach of children. The presence of multiple families living in the same home further impedes safe storage practices. In this study, families stored all personal products including medications and household cleansing agents with them in their bedrooms rather than in common areas such as the bathroom.⁴⁶

It is important to consider employment of bilingual staff as public educators when attempting to expand public awareness. The benefits of a bilingual educator include the ability to provide programs directly to an audience and eliminate the need for a translator. A lack of bilingual providers was the most significant barrier identified for Spanish speaking women interviewed about injury prevention techniques.²⁶­Recommendations for more effective outreach to Latino populations include television advertisements and distribution of written information at schools, churches, and doctor offices.⁷⁴ Health education programs including mass media campaigns, designed to accurately reflect the cultural identity—language, beliefs, roles—of the targeted population are more likely to be accepted. Storytelling has also been a recommended strategy for health education among many cultures.⁴⁴ When asked to provide suggestions for poison prevention education, responses included Spanish radio and video programs as well as brochures that incorporate culturally appropriate values. Including messages into widely recognized media such as telenovelas should also be considered when developing information dissemination channels. Most parents reported interest in learning from PC staff, doctor, or a teacher.¹⁶

Field testing concepts and materials are important for the development and distribution of appropriate information for multicultural populations. Further work is needed to examine cultural beliefs related to poison prevention use of and access to the PC. It is important to address cultural beliefs related to use of herbal and other complementary medicines.³⁰ New education programs are needed to reach multilingual and multicultural targeted populations communities across the country. Programs may be more successful if individuals trust and view a source as credible, particularly when cultural attitudes and beliefs closely resemble their own.^16,35,44 In addition, promotoras or community health workers should be considered to deliver primary prevention information in the Hispanic community for building relationships with parents and overcoming cultural barriers.^16,40

Health Literacy/Numeracy

Health literacy is defined as “the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions.”⁷² Health literacy encompasses the ability to read, understand, and discuss medical information. Research from the US Department of Education shows that only 12% of US English speaking adults have proficient health literacy skills.⁷² Older adults, Hispanic adults, immigrants, those with less than a high school degree or GED, and low income individuals are at highest risk for low health literacy.³⁷ People with low functional health literacy abilities are less likely to understand written and verbal health information, medicine labels, and appointment information.³⁷ This type of health information is often ­written at reading levels of at least tenth grade or higher.¹⁸ The recommended ­reading level for written information is sixth grade. Most Americans are able to understand medical information at this level.⁷² In addition to ­reading level, use of graphics, font style, color, type size, and layout are important components when developing print material.^18,72 Recommendations for nonprint methods for communicating health information include visuals (posters, fotonovelas, pictographs), action-oriented activities (role-play, theater, storytelling), audiovisuals (videos, DVDs), and improving patient–provider communication.^16,18,52,72

Warning and medication labels are often difficult to understand. The inability to read these warning labels in English presents a barrier for safe storage and safe use of medication and products.⁴⁶ Identification of products often includes brand recognition.⁴⁵ Instructions for proper use and warnings may not be understood from the label independent of language.

In order to address medication safety issues, particularly with medication labels, a number of studies have evaluated ways to simplify the information provided. New recommendations for standardized prescription medicine labels incorporate four specific time periods (morning, noon, evening, and bedtime) and plain language techniques on the container.^76,77 Similarly, recommendations for nonprescription medicine labels have been developed.⁸¹

The effects of health numeracy as a distinct component of health literacy are presented in the literature.^48,64 Numeracy is an element of health literacy and involves the ability to use numeric information to make effective health decisions in daily life.³ This also includes concepts of risk, probability, and the communication of scientific evidence.^48,62,64 Health-related tasks including measuring medications, scheduling appointments, and refilling prescriptions rely on applied numeracy skills.^62,64 Patients managing multiple prescription and nonprescription regimens will lead to potential medication errors.⁷⁶ Educators need to understand the importance of interventions that accurately assess numeracy levels and appropriately address health outcomes. Recommendations for techniques to improve understanding of numeric information include simplifying concepts, using plain language strategies, and utilizing “teach-back” patient understanding strategies.^3,72

Applying Health Education Principles to Poison Education Programs

Health education involves planning, implementing, and evaluating programs based on theories and models. These models offer direction for educators with health promotion planning.⁴² There is a need to increase the number of poison educational programs incorporating health education principles. This includes educational efforts designed to reach individuals through community based programs and media campaigns.

Both the Health Belief Model (HBM) and Social Cognitive Theory (SCT) incorporate the concept of “self-efficacy” and are applicable when designing poison prevention interventions and mass media campaigns. Self-efficacy is the individual’s belief that he or she will be able to accomplish the task requested.^13,18,41,58 Many health educators believe that self-efficacy is necessary to enable behavior change. The SCT suggests that individuals, the environment, and behavior are intimately and inextricably interrelated.⁴¹ The HBM suggests that individuals are more likely to make health behavior changes based on perceived risk susceptibility, severity, potential barriers, and self-efficacy. These decisions are made when actions are seen as potentially more beneficial to the individual than the perceived risks associated with surmounting the current barriers.¹³

In one study, the HBM approach was used as a framework for poison prevention and for the assessment of barriers to PC use. Questions for focus group participants were developed based on the principles of HBM—that is, perceived susceptibility, severity, benefits, barriers, and self-efficacy related to the health action requested. Most of the mothers viewed poisoning as an emergency and felt it was a health concern for their children. Cues to action are also a component of the model and involve discussions about poison prevention or related information. Participants recommended using community based venues and culturally appropriate information to expand awareness about poison prevention and the poison center.⁹

The HBM and SCT approaches were used to develop the questions for focus groups in both English and Spanish. These questions addressed issues related to poison prevention (severity and susceptibility), the services of the PC (including barriers), and suggestions for education. Focus group participants suggested the use of modeling to reinforce real life scenarios in which a mother handles the poisoning emergency with the staff at the PC with a positive outcome.²⁹ As a result, a video was developed addressing these ideas. Two poisoning situations in which a mother calls the center are depicted. One involves home management (ingestion of bleach) and the second involves taking the child to the emergency department (swallowing grandmother’s antihypertensive pill). The video and correlated teaching guides are available in English and Spanish.³⁰

It is important to develop questionnaires that will be accepted and understood by the target population. A Spanish language instrument that addresses home safety beliefs using the HBM framework was developed and tested. Low income, monolingual, Spanish speaking mothers of children younger than 4 years of age were interviewed about perceived susceptibility, severity, barriers, and self-efficacy factors affecting unintentional home injuries including poison prevention measures. Barriers identified include literacy skills and access to bilingual health information.²⁶

The HBM supports the idea that a “teachable moment” may be the ideal opportunity to present poison prevention interventions.^23,56 People may be more open to health information after experiencing a traumatic experience.¹² Events such as an unintentional poisoning exposure may motivate individuals to behavioral change. Applying HBM principles suggests that individuals will make changes in terms of poison prevention when or if they view the severity and susceptibility of a poisoning to be high in the home. Many languages are enriched by cultural variations that must be incorporated into poison education programs and best practices for outreach. Our goal as educators is to provide efforts using models that have been tested and evaluated for addressing focused community efforts in each population served by the PC.

SUMMARY

• Poison center public education efforts must encompass needs assessments, program development, implementation, and evaluation.

• Focus groups with caregivers of young children conducted across the country have consistently identified barriers to calling poison centers. These include calling 9-1-1, fear of being reported to child welfare agencies, and lack of confidence in handling poisoning emergencies.

• Using health education theories and models, programs should be developed that address these barriers and encourage caregivers to use the services of the PC appropriately.

• Education programs focusing on the needs of older adults and promoting using the poison center as a resource for medicine safety should be designed.

• Cultural, health literacy, health numeracy, and language needs of target populations are important considerations when planning poison education programs.

References

Poison Centers and Poison Epidemiology

HISTORY

In 1950, the American Academy of Pediatrics created a Committee on Accident Prevention to explore methods to reduce injuries in young children. A subsequent survey by that committee demonstrated that injuries resulting from unintentional poisoning were a significant cause of childhood morbidity. Simultaneously came the realizations that a source of reliable information on the active ingredients of common household xenobiotics was lacking and that there were few accepted methods for treating poisoned patients. In response to this void, the first poison center was created in Chicago in 1953.¹⁰² Although initially designed to provide information to health care professionals, both the popularity and the success of this center stimulated a poison center movement, which rapidly spread across the country. The myriad of new poison centers not only offered product content information to health care professionals, but also began to offer first aid and prevention information to members of the community.

In the 60 years that have since passed, countless achievements have been realized by a relatively small group of remarkably altruistic individuals. Throughout this time, poison services have remained free to the public, highlighting their essential role in the American public health system. Many of the legislative and educational accomplishments, which are chronicled in Chap. 1, have directly reduced the incidence and severity of poisoning in children.^98,110,116 Concurrently, the number, configuration, and specific role of poison centers have shifted in response to public and professional needs.^50,125

Modern regional poison centers are staffed by highly trained and certified health professionals who are assisted by extensive information systems. Support is provided by 24 hour access to board certified medical toxicologists and consultants from diverse medical disciplines, the natural sciences, and industry. The role of the current American poison center can be best summarized as follows:

• Maintaining and interpreting a database of xenobiotics

• Reducing health care costs related to poisoning through:

  • Providing information and advice to the public to prevent unnecessary hospitalizations following exposure

  • Providing information and advice to health professionals to improve the diagnosis and care of patients who present to health care

• Collecting epidemiologic data on the incidence and severity of poisoning

• Integrating epidemiologic data as part of the public health surveillance system

• Educating health care professionals on the diagnosis and treatment of poisoning

• Contributing to the science of toxicology

In the past, poison centers were evaluated based on number of incoming calls and measures of community awareness. Current emphasis should be placed on evaluating health outcomes such as admissions to the intensive care unit, length of stay in hospitals, and total health care expenditures. One crucial test of the utility of modern poison centers will be their ability to help reverse the current trend in the United States of increasing adult mortality from prescription drug poisoning.⁶⁷ This chapter explores some of the critical roles of US poison centers and attempts to offer a vision of the future. An overview of the composition of poison centers worldwide can be found elsewhere.⁹⁶ Unique issues facing poison centers in other countries are discussed in Chap. 137.

MAINTAINING AND INTERPRETING A DATABASE OF XENOBIOTICS

The first toxicology database created in the United States was a set of cumbersome 5 × 8-inch index cards produced in the 1950s by the US National Clearinghouse of Poison Control Centers.¹⁰² When it grew to include more than 16,000 cards, the sheer volume of space required to store this information, and the extensive time necessary to manually search these cards, created the necessity of a central repository, such as a poison center. As available information grew, a rapid expansion of information technology occurred, and the unwieldy index card database was privatized and transformed into microfiche. Although this resource was physically smaller, specialized equipment was required, and a search was still time consuming. Numerous encyclopedic and clinical textbooks were written to supplement the database and provide resources for the office or the bedside. With the growth of the computer age and the Internet, the computer program known as POISINDEX was established to replace the microfiche format as the major source of data on the contents of innumerable household and industrial products, drugs, and plant and animal xenobiotics. POISINDEX also provides uniform management strategies for many potentially toxic exposures. Over the years many proprietary competitors to POISINDEX such as TOXINZ and TOXBASE have gained recognition as valuable tools. Additionally, open source programs such as WIKITOX provide free information to both health care professionals and members of the public.

With this evolution of information technology, poison centers are no longer perceived as the sole guardians of toxicology information. Although these services are still essential for the public at large, and those professionals away from their computers or smart phones, a predictable decline in poison center utilization has paralleled this growth in availability of information. A 1991 study in Utah demonstrated that 82.6% of emergency physicians who had POISINDEX available in their institutions no longer routinely consulted the poison center.²⁷ A similar 1994 New York study suggested that 76% of physicians who had POISINDEX in their emergency departments (EDs) perceived that this decreased their own use of their poison center.¹²¹ These studies suggest that poison centers were more likely to be called for patients with acute and symptomatic overdose and less likely to be contacted for chronic toxicity, asymptomatic patients, and adverse drug reactions.

An initial analysis might suggest that this is an acceptable trend for health care professionals in that it both allows physicians to respond more rapidly to patient needs and for poison centers to be more available to those individuals, especially non–health care professionals, who do not have access to this information system. In fact, one regional poison center model demonstrated that an integrated voice response (IVR) system effectively reduced human interactions for medication identification by more than one-half.⁷⁵ By extension, it might be suggested that both the public and health care professionals can easily access the same information as poison specialists, making the human interaction nearly obsolete. However, this practice of “not calling” not only undermines the efforts of poison centers to gather epidemiologic data (see later) but also creates an understanding gap. In other words, the interpretation of the data is as essential (or more essential) than the data itself. For example, some commonly used sources of toxicology information such as the Physicians’ Desk Reference and material safety data sheets occasionally provide information that may be inaccurate, potentially misleading, or severely limited.^19,56,87 Likewise, reviews of drug interaction programs designed for mobile devices demonstrated significant variability between individual programs and superiority of larger online resources.^5,37,94,97 Although POISINDEX routinely provides more accurate information regarding overdose, it is only updated quarterly, cannot be expected to adapt to ongoing epidemiologic trends such as regional variations in substance use, and is incapable of judging adequacy or communications or the subtleties contained in natural language.

The best source for essential new information is skilled professionals who specialize in poisoning. In addition, because most databases are designed to provide information about known entities, they perform poorly when dealing with unknown and unclear scenarios—especially long and complicated differential diagnoses. For example, consider the case of a clinician caring for a lethargic child whose only medication is Zantac syrup. After the other causes of altered mental status have been excluded, the clinician considers drug toxicity. Consultation with standard references suggests that altered consciousness would not be expected with use of this medication. However, a certified poison specialist at a regional poison center recognizes the potential for drug error, has the physician review the syrup bottle in question, and then calls the pharmacy where the drug was provided. The poison specialist learns that although the prescription was written for ranitidine (Zantac), the bottle actually contains cetirizine (Zyrtec syrup), which could account for the child’s symptoms.

Thus, although originally designed as providers of information, poison centers are in reality valued consultants, with staff members who not only provide content information but also interpret clinical material and link both to appropriate management strategies. This goal can only be achieved through rigorous training and certification and recertification criteria designed to provide valued up to date interactions with health care professionals. Access to computer programs can never be considered a substitute for a thoughtful human analysis. Computers do not recognize anxiety, inappropriate questions, and other subtle issues that can only be appreciated with human interactions.

Another illustrative example of the value of poison centers can be drawn from the use of flumazenil for benzodiazepine overdose (Chap. 74 and Antidotes in Depth: A22). Although it may easily be determined by anyone capable of using a resource that flumazenil is an antidote for benzodiazepine overdoses, many subtle characteristics of the patient or the overdose often contraindicate its use. A prospective study determined that when flumazenil was used before consultation with the poison center, contraindications were present in 10 of 14 (71%) cases, resulting in one serious adverse event.²² In the study mentioned earlier, although physicians with access to POISINDEX were less likely to call the poison center, 86.7% still felt that using the poison center to gain access to a physician toxicologist was a valued resource.²⁷ Many poison centers are linked with centers for poison treatment, which are health care facilities that can provide both bedside consultation and unique diagnostic and therapeutic interventions for a subset of patients with severe or complex poisoning.¹ The benefits of consultation are discussed later in Health Care Savings.

PROVIDING INFORMATION AND ADVICE TO THE PUBLIC AND TO HEALTH PROFESSIONALS

In 2011, poison centers in the United States interacted with the public and health professionals more than 3.5 million times.¹⁸ While the financial value of these interactions will be discussed in the section on health care savings below, two major limitations to the success of poison centers were highlighted by recent studies. The first, which should be intuitively obvious, stems from the fact that poison centers are remote from the patient and can, therefore, only make decisions based on the information provided to them. Although poison information specialists are highly skilled and use a variety of communication styles to obtain the most accurate information,⁴⁸ the quality of the information impacts on the utility of their recommendations. The greatest concern often is the estimation of the actual dose of an exposure. In a 3.5 year study of all children referred by a poison center to a health care facility for the determination of the presence of either a methanol or an ethylene glycol blood concentration because of the history of an exposure, only 21 of 102 children had a measurable concentration.⁷⁸ While this has serious limitations on the interpretation of poison center data,⁶² the implications for clinical care are even greater. Likewise a human volunteer study demonstrated that adults are totally incapable of determining residual volumes in containers or describing the actual volume of semiquantitative descriptors such as “a small mouthful” or “a gulp.”⁶¹ Because critical decisions are made based on the history of ingestion or amount ingested, a clear challenge for poison centers is to develop methods to improve the accuracy of this information. Digital imagery may provide a useful method of assisting caregivers with determination of residual container volumes by allowing specialists to clarify container sizes and residual volumes.

The second challenge involves the gap that exists between recommendations that are made by poison centers and those that are accepted. Two recent papers highlight this concern. In a 7 year analysis of poison center recommendations for the administration of high dose insulin and glucose therapy, the recommended treatment was actually administered only 50% of the time.⁴⁹ Similarly, in a 5.5 year study of calcium channel blocker and β-adrenergic antagonist overdoses at a different poison center, high dose insulin and glucose therapy was only started in 42% of cases where it was recommended, and intravenous fat emulsion was only given in 33% of cases where it was recommended.⁴¹ Because both these therapies are considered effective and potentially life saving (Antidotes in Depth: A17 and A20), ­poison centers need to evaluate the reasons these recommendations are not accepted and explore methods to improve communication with providers. The use of on-site medical or clinical toxicology faculty liaisons may help reduce these gaps.

COLLECTING POISON EPIDEMIOLOGY DATA

In 2007, the US Centers for Disease Control and Prevention (CDC) reported that poisoning fatality surpassed both motor vehicle crashes and firearms to become the leading cause of injury related fatalities.⁹³ This trend has continued and is largely influenced by an epidemic of prescription opioid abuse.⁶⁷ Understanding the evolving trends in poisoning is essential to the development of enhanced surveillance, prevention, and education programs designed to improve medication prescribing, drug safety, and to reduce unintentional poisoning. Although data can be analyzed from numerous sources, such as death certificates, hospital discharge coding records, and poison centers, it is essential to recognize the biases that are inherent in each of these reports. Because not all significant poisonings result in either hospitalization or fatality, data from poison centers appear to offer a unique perspective.

Unfortunately, the term “poisoning” is often defined differently and therefore may be confusing. In this text, “poisoning” is used to denote any exposure to any xenobiotic (drug, toxin, chemical, or naturally occurring substance) that results in injury. Yet the data collected and disseminated by poison centers are defined by the term “exposures.”^{13, 14, 15, 16, 17, and 18,76,117, 118, and 119} Many exposures are of limited toxicologic consequence either because of the properties of the xenobiotic involved, the magnitude or duration of the exposure, or the uncertainties regarding whether an actual exposure has occurred. Therefore, data collected by poison centers represent a limited and ill-defined measure of poisoning.

The situation is further confounded by multiple biases that are introduced by the actual reporting process, which first and foremost is voluntary and passive. Because most calls concern self reported data from the home and are never subsequently confirmed, a significant percentage of the data generated to date may actually represent only potential or possible exposures, which can introduce large statistical errors into the database. This is highlighted by the 21 of 102 children who tested positive for a toxic alcohol discussed above.⁷⁸ Despite the fact that only those 21 children were definitively exposed and potentially poisoned, all 102 were entered into the database as exposures. If these figures are representative of the rest of the data set, then they suggest that an actual ingestion does not occur in the vast majority of reported unintentional exposures in children. However, they do emphasize that in all of the cases a toxin was in an unacceptably close proximity to a child. Also, current events, hoaxes, and media awareness campaigns all may influence self-reporting rates.⁸¹ Furthermore, to report a possible exposure a caller must have a telephone, probably speak English, and have some degree of health literacy and numeracy.^80,115 Although telecommunications devices for the hearing impaired and translation services exist, they are rarely used. Enhancement of technology to facilitate the accurate exchange of information between poison specialists and either hearing impaired callers or those who do not speak English is essential to the success of poison centers. While text message is an interesting option, preliminary data suggest that text messaging encounters take way too long to be productive.⁹⁹ Another would be to entertain more active reporting systems automatically triggered directly by hospital laboratory values. Such a system would explore cognitive behavior of clinicians around reporting and develop a true understand of the epidemiology.

Under the present passive system, when hospitals report exposures to the poison center, a comparison of the hospital chart with the poison center record shows good agreement, demonstrating an accurate exchange of information.⁶⁴ Unfortunately, a reporting bias similar to that described above is well recognized regarding professional utilization of poison centers and has been called the Pollyanna phenomenon.⁵⁷ For example, in the spring of 1995, poison centers in the northeast United States began to receive numerous reports of severe psychomotor agitation and other manifestations of anticholinergic syndrome in heroin users. In the initial phase of the epidemic, most of the callers requested assistance in establishing a diagnosis, determining possible etiologies, and raised questions regarding treatment with physostigmine.⁵⁸ Although the epidemic continued for many months, once the media announced that the heroin supply was tainted with scopolamine, and clinicians became familiar with the indications and administration of physostigmine, call volume decreased. Stated simply, health care professionals are less likely to call the poison center regarding issues with which they are familiar, are of little clinical consequence, or are not recognized as being related to a poison. Thus, a bias is introduced that results in a relative over reporting of new and serious events and a relative underreporting of the familiar or very common, unrecognized poisoning, and those exposures or poisonings that are apparently inconsequential. Numerous comparisons support this contention. Investigators who rely on published data from poison centers as a sole source of epidemiologic information demonstrate a failure to understand the complexity of poisoning data and the aforementioned consequential limitations of poison center–derived data.

Fatal Poisoning

A 4 year study compared deaths from poisoning reported to the Rhode Island medical examiner with those reported to the area poison center.⁷⁹ Not surprisingly, the medical examiner reported many more deaths: 369 compared with 45 reported by the poison center. Although most of the cases not reported to the poison center were victims who died at home, were pronounced dead on arrival to the hospital, or those in whom poisoning was not suspected until the postmortem analysis, 79 patients who subsequently became unreported fatalities were actually admitted to the hospital with a suspected poisoning. In 10 of these cases, the authors concluded that a toxicology consultation might have altered the outcome. Examples of interventions that, if recommended and performed, might have resulted in a more favorable outcome included the proper use of antidotes such as naloxone for an opioid overdose, N-acetylcysteine for acetaminophen (APAP) poisoning, the cyanide antidote kit, sodium bicarbonate for a cyclic antidepressant overdose, hyperbaric oxygen for carbon monoxide poisoning, hemoperfusion for a theophylline overdose, and hemodialysis for a lithium overdose. While the xenobiotics may have changed since this study was performed, the fundamental principles highlighted remain relevant.

Likewise, when medical examiner data were analyzed in Massachusetts, more than 47% of poison fatalities had not been reported to the poison center.¹⁰⁷ A California study evaluating 358 poisoning fatalities reported to the medical examiner showed that only 10 poison center fatalities were reported over a similar time period, demonstrating an even more consequential reporting gap.⁷ Once again in this study, whereas the majority of underreporting was with respect to prehospital deaths (68%), only 5 of 113 hospitalized patients who ultimately died were reported to the poison center. Additionally, a cross-sectional comparison of national mortality data with poison center data for agricultural chemical poisoning demonstrated a similar trend of underreporting to poison centers of seriously poisoned admitted patients who became fatalities.⁷² Furthermore, when data for an entire year from the National Center for Health Statistics were compared with the same year of data from the American Association of Poison Control Centers (AAPCC), it was apparent that the AAPCC data captured only about 5% of annual poison fatalities.⁶³

More recent analyses have highlighted a remarkable trend. When 11 states evaluated trends in poison-related mortality from 1990 to 2001, an average increase of 145% was noted.¹⁰⁶ A more comprehensive investigation of the National Vital Statistics System accessed via the CDC’s Web-based Injury Statistics Query and Reporting System database demonstrated a 5.5% increase in injury related mortality from 1999 to 2004. Mortality from poisoning accounted for 61.9% of the increase in unintentional injury, 28% of the increase in suicide, 81.2% of the increase in death from undetermined intent, and more than half of the total increase injury-related mortality.⁹³ As of 2004, death from poisoning surpassed firearms and became the second most common cause of injury-related fatality. While most of the fatalities are in adults, a review of the entire 2010 AAPCC database only found 74 reported fatalities in children.²³ Focusing on poison center data alone would produce the erroneous assumption that poisoning-related fatalities were not a significant public health concern. In actuality, poisoning is a significant concern in that other programs designed to reduce deaths from motor vehicle crashes and firearms have been largely successful whereas decades have gone by without a major intervention targeting poison related fatality.

It is logical to assume that similar disparities exist regarding the reporting of nonfatal poisonings. The resultant gap in public health data needs to be addressed through improved definitions, epidemiology, reporting, and analysis of poison-related data systems. This inequity has developed through a long-standing tradition of poison centers to focus attention and concentrate on the largely benign exposures in children. The emphasis needs to be redirected toward seriously ill poisoning, utilization of the intensive care unit, and other markers of actual poisoning rather than health care utilization for benign events. The necessary data for such an evaluation may already exist, but the challenge will be in linking the data sets to provide a meaningful analysis.

Nonfatal Poisoning

An outreach study in Massachusetts determined that hospitals geographically close to a poison center reported their cases almost twice as often as hospitals remotely located (46% vs. 27% of total cases).²⁸ Additionally, the authors noted that private physicians were less likely to report cases than residents in training. A one year retrospective review demonstrated that only 26% (123 of 470) of poisoned patients who were treated in a particular ED were reported to the poison center.⁵⁹ Interestingly, only 3% of inhalational exposures were reported, compared with 95% of cyclic antidepressant ingestions. The authors also noted, as suggested above, that reporting decreased when comparable exposures occurred over a short period of time. Finally, in the physician survey study cited earlier, physicians reported that they would “almost never” contact the poison center for asymptomatic exposures (62.9%), chronic toxicity (50.4%), or simply to assist in establishing a reliable database (90.2%).²⁷ This statement is most likely accurate even in jurisdictions in which the reporting of all or select exposures is incorporated into public health laws.

Occupational Exposures

Xenobiotic exposure occurs commonly in the workplace. As a result of the long-recognized association between occupational exposure and illness, several federal and state government funded agencies, such as the National Institute for Occupational Safety and Health, Occupational Safety and Health Act, and the Agency for Toxic Substances and Disease Registry (ATSDR), exist to prevent occupational illness, to educate the public, and to collect data on exposures to occupational xenobiotics. Legislation provides for mandatory reporting in some instances and offers workers job protection for voluntary reporting. Poison centers also provide information on occupational exposures and collect data. Once again, there are discrepancies between the poison information data and the data collected by governmental agencies. A six month survey in California noted that only 15.9% of the occupational cases reported to the poison center were captured by a state occupational reporting system.⁹ The most common occupational toxicologic illness—dermatitis—was even further underrepresented in these cases. A follow-up study by the same authors demonstrated that more than one-third of calls came directly from the individual worker, 70% of whom were unaware of the link between their occupation and their symptoms.⁸ Although these data suggest that poison centers can provide substantial assistance following occupational exposures, one author expressed concern, noting in a follow-up study that the poison center failed to provide an adequate epidemiologic assessment in that it did not identify an average of 12 other people per workplace who were also potentially exposed in addition to the index case.¹¹ A 1999 survey of poison centers concluded that “responses to work-related calls are inadequate” and suggested that written protocols might be helpful.¹²

Adverse Drug Events and Xenobiotic Errors

Although the actual numbers are a source of controversy, data suggest that a striking number of adverse drug events (ADEs) occur each year in the United States, with many resulting in death.^20,31,77 The ease of 24 hour telephone access, combined with the ability to consult with a health professional, make poison centers ideal resources for reporting of ADEs.³⁰ Yet, more than 76% of physicians surveyed stated that they would “almost never” contact the poison center regarding adverse drug events.²⁷ Moreover, 30 of the 56 (53.6%) poison centers surveyed stated that they had not submitted any of their ADE data to the US Food and Drug Administration’s MedWatch program.³⁴ Many of the other centers reported only partial compliance with the MedWatch system.³⁴ Biases may lead to disproportionate reporting of adverse events related to newer drugs skewing the interpretation of the data. For example, although bleeding may occur from both coumadin and dabigatran, it is easy to believe that reports would be more likely to be generated for the newer drug.

Prescription drug errors are another source of potential poisoning. Retrospective review of poison center data suggests that many of these errors are reported. In one report, the poison center provided valuable feedback to pharmacists and physicians about these errors. Ideally, reporting to the state board of pharmacy would assure that proper surveillance and counseling continue. The poison center would seem to be ideally suited to perform this function.¹⁰⁴ Unfortunately, while pharmacists are ideally positioned to identify prescribing errors, data suggest that pharmacist utilization of poison centers is poor.²

Drugs of Abuse

Poison centers also collect data on exposures to drugs of abuse and misuse. These data consist largely of calls for information from the concerned public and reports of overdose requiring health care intervention. Although ethanol, tobacco, and caffeine are the most common xenobiotics used in society, these cases are rarely reflected in poison center data, with the exception of unintentional exposures in children. In fact, because most substance abuse does not result in immediate interactions with the health care system, other databases such as the National Institute of Drug Abuse Household Survey (now referred to as the Monitoring the Future Study) might better reflect substance abuse trends. Yet even this database has significant limitations.^6,54 Because poison centers are more focused on immediate health care effects of exposures, it could be argued that only those cases in which health care interaction is required are of value in the database. Since poison centers collect data in real time, centers are ideally positioned to report on emerging trends and sentinel events. Recent examples include poison center experiences with trends opioid abuse in teenagers,^51,111 bath salts,⁸⁸ synthetic cannabinoid receptor agonists,⁸⁹ and adulterated cocaine.¹¹²

Grossly Underreported Xenobiotics

As discussed previously, there is little doubt that ethanol and tobacco are the most common xenobiotics intentionally used in our society. Although their toxicologic manifestations can be acute and severe, chronic subcl­inical poisoning often goes unnoticed for many years. Similarly, more than 500,000 American children have lead concentrations above 10 μg/dL and polychlorinated biphenyls can be found in countless adults and children. We must remain cognizant of these large-scale exposures, such as bisphenol A, when we read that plants, cleaning products, and cosmetics comprise the most common exposures to xenobiotics¹⁸ are the most commonly “reported” exposures.

Integrating Epidemiologic Data as Part of the Public Health Surveillance System

With the current limitations of the poison center data, it should be clear that neither the numerator nor the denominator of the actual number of poisonings can be easily appreciated. However, analysis of these data for trends may be more useful because the inherent biases involved in poison center reporting are probably consistent over many years. Increasingly, poison center data are being used as part of surveillance and prediction models,^46,123 often that extend beyond poisoning to other public health concerns.¹⁰⁵ Rapid reporting in collaboration with the CDC highlights an essential partnership.^38,55,89 Efforts should be directed to encourage reporting to poison centers by such enhanced access methods as Web-based forms for passive reporting, a direct interface between laboratory and hospital databases that actively transmits data to poison centers, and linkages to other agencies that collect reports of poisoning such as state and local health departments. Additional resources should be directed at improved case definitions (distinguishing asymptomatic exposure from poisoning) and integration with other essential databases such as MedWatch, the National Vital Statistics System, and the National Center for Health Statistics.

Despite its limitations, poison center data have significant utility. It is often an exposure rather than an actual poisoning that provides the impetus for contact with health care. For those exposures that are unlikely to be consequential, the poison center can intervene to prevent potentially harmful attempts at home decontamination and costly unnecessary visits to health care professionals. Interaction with parents at a time of perceived crisis also provides a “teachable moment” (Chap. 135) that may help prevent a more consequential exposure in the future. For those exposures that may result in poisoning, the period of time immediately following exposure is an ideal moment to initiate first aid measures designed to prevent or lessen the severity of poisoning. For both of these reasons the cost, benefits, and efficacy of poison centers especially regarding home calls must be measured in terms of exposures and not poisonings.

HEALTH CARE SAVINGS

When visits to pediatric EDs for acute poisoning were analyzed, one study demonstrated that 95% of parents had not contacted the poison center before coming to the hospital and 64% of those children required no hospital services and could have therefore profited from a poison center interaction.²⁹ By contrast, when parents called the poison center first, fewer than 1% sought emergency services afterward. When 589 callers to one poison center were surveyed, 464 (79%) stated that they would have used the emergency care system if the poison center were unavailable.⁶⁹ In a similar study, 36% of callers would have selected a more costly alternative if the poison center were unavailable.¹⁰ Likewise, when primary care givers were surveyed, over 80% said that they would activate 9-1-1 if there were no poison center.³ Poison center data confirm that approximately 75% of reported exposures that originate outside of health care facilities can be safely managed onsite with limited telephone follow-up. Suggesting simple techniques or reassurance can successfully reduce hospital visits for patients who typically call poison centers which, as defined, may only represent a potential exposure. The use of established protocols, especially for unintentional exposures in children clearly reduces emergency department referral rates.⁶⁰ These interactions can be followed by distribution of simply written prevention literature to improve use and retention. Unfortunately, this approach is less applicable to adults and the population as a whole.

Limited data suggest that direct bedside consultation and care help reduce length of hospital stay and health care costs.³⁶ Yet poison centers operate remotely. In one assessment, consultation with a poison center reduced length of stay by nearly 3 days.¹¹⁴ Similarly, when the poison center was consulted for patients already in the hospital, length of stay and costs were reduced by 1.9 days and nearly $5000.²¹ This experience has been replicated outside the United States where poison center consultation resulted in a decreased length of stay of more than 3 days, respectively.⁵² Strongly encouraged or mandated interactions with poison centers might help reduce the cost of health care, hospital overcrowding, and access to limited resources such as antidotes and hemodialysis.

The national average cost to the poison center for a single human exposure call is on the order of $35.¹²⁵ A federally funded study concluded that, in one year, poison centers reduced the number of patients who were treated but not hospitalized by 350,000 and reduced hospitalizations by an additional 40,000 patients, for a cost savings of more than $3 million in 1996 dollars.⁸⁶ Each call to a poison center prevented at least $175 in subsequent medical costs, providing strong theoretical evidence to support the cost efficacy of poison centers. In fact, two natural experiments support these calculations. In 1988, Louisiana closed its state sponsored poison center. During the year that followed, the cost of emergency medical services for poisoning in Louisiana increased by more than $1.4 million. This additional expenditure represented a greater than threefold increase above the operating cost of that center.⁷¹ Similarly, because of financial disputes in California, direct access to the San Francisco poison center was electronically restricted for one major county, with a telephone recording referring callers instead to the county 9-1-1 system for assistance.⁹⁵ The result of each blocked call was to increase health care costs by approximately $33. Moreover, these calculations cannot account for the unmeasured benefits to society from poison center interventions that reduce waiting times for ambulance availability and hospital treatments because of lower volumes, money saved by the prevention or reduction of injury from early intervention, or lives saved by enhancing access to or utilization of the health care system for seriously poisoned patients. In El Paso TX, cooperation between emergency medical services and the poison center was able to reduce ambulance dispatches by 1750 over 5 years.⁴ Overall estimates place the rate of return for poison center funding between 11 and 36:1.^66,108

However, many barriers prevent a person from calling a poison center, including lack of familiarity with its available services, intellectual and cultural factors, language difficulties, and confidentiality concerns.^35,70,80,115 Epidemiologic studies demonstrate that areas of increased population density, such as major urban communities, with high percentages of minority inhabitants have lower utilization of poison center services.¹¹³ Additional barriers include the absence of caregiver comfort with the extensive personal contact provided by the health care system and a concern regarding implications of child abuse or neglect when reporting to agencies such as poison center, many of which have governmental ties.¹⁰³ Data demonstrate that public educators can help overcome some of these barriers.¹⁰⁹ One good example of an effort to overcome reporting barriers was the institution of a single national toll-free number for poisoning (1-800-222-1222). Although it is clear that this intervention improved access and increased total calls to the poison center,⁷⁴ it has yet to be determined if this has altered the patterns of use.

PROVIDING EDUCATION FOR THE PUBLIC AND HEALTH PROFESSIONALS

Poison center staff work closely with physicians, community health educators, community support groups, and parent–teacher associations to develop poison prevention activities.⁸²Table 136–1 lists common strategies advocated to prevent poisoning. Poison centers are also actively involved in enhancing training programs for paramedics,⁴⁷ medical students,⁶⁸ pharmacy students,⁴⁰ and resident physicians,^40,91,122 and are an integral part of postgraduate training programs in medical toxicology fellowships.

As stated previously, there is an inherent risk in both enhanced public and professional education programs. Currently, the decreased telephone utilization of a poison center could be both the result of a decrease in the incidence of exposures or poisonings or an enhanced understanding of the prevention, diagnosis, and treatment of poisoning. Although education should never be viewed as detrimental, programs must include an emphasis on the continued use of poison centers to assure access to most current information in a rapidly changing discipline that only develops through an ongoing dialog between health care professionals and poison specialists. In actuality, as a result of the ongoing analysis of incoming calls, the knowledge base has the potential to change as rapidly as the calls are reported. This is far more rapid than can occur in any published literature or electronic database. Thus, additional emphasis should be applied to routine utilization of the poison center as a public health tool to improve the accuracy of epidemiologic data. Reporting of rare or suspected events can serve as sentinel efforts that help identify consequential adverse drug opportunities long before normal postmarketing surveillance tools identify areas of concern.

On the other hand, outreach programs that advise the public to access free services for inconsequential events can easily overwhelm an already stressed system of responding to incoming calls by demanding an immediate response to the less serious calls in an appropriate time frame. Public education and public health must both be considered to assure that poison centers are staffed with the appropriate number of skilled individuals to respond not only to daily events, but also to address surges in calls that may be the result of true epidemics or responses to media announcements. Increasing calls to demonstrate increased utilization offers no public health advantage if the utilization is inappropriate or if seriously ill or potentially ill callers lose access to timely responses.

DEVELOPMENT OF FUTURE PUBLIC HEALTH INITIATIVES

The initial public health efforts of poison centers focused on attempts to alter product concentration and to enhance product labeling and packaging. These clearly beneficial endeavors should continue and must evolve. However, current events have also increased poison center activities in preparedness for mass gatherings and disasters resulting from radiological, biological, and chemical terrorism.^53,73 Additional links with governmental agencies such as the CDC and ATSDR will expand the role of medical toxicology in community health. The need for 24 hour rapid access to centralized information, existing data entry and retrieval systems, and links to experts in medical toxicology and emergency medicine helps to place poison centers in critical roles in both local and national initiatives. Important contributions have included development of triage and treatment protocols^{24, 25, and 26,32,33,39,43,60,83, 84, and 85,90,92,100,101,120,124} and assessments of antidote supplies.^42,44,45Table 136–2 summarizes initiatives that require creation or enhancement to improve poisoning epidemiology data. Many of these are discussed extensively in a report from the Institute of Medicine.⁶⁵

SUMMARY

• Public education efforts help reduce the likelihood of exposure.

• Provision of basic management advice helps to diminish the consequences of a poisoning once an exposure has occurred.

• Reassurance and proper basic management help to curtail unnecessary utilization of expensive health care.

• Interactions with health care professionals streamline the care of poisoned patients saving hospital days and health care expenditures.

• Collaboration with public health authorities will identify, inform, and help mitigate the consequences of ongoing toxicologic events.

• Data on exposures have been effective to create legislation to further limit poisoning by altering contents or improving packaging or labeling.

Acknowledgment

Richard S. Weisman, PharmD, contributed to Table 136–1 in previous editions.

References

International Perspectives on Medical Toxicology

INTRODUCTION

Poisoning is a worldwide problem, but the major effects are felt in the developing world. At least 250,000 to 350,000 people die every year from acute pesticide poisoning,⁷² and an estimated 20,000 to 94,000 humans die each year from snake bites,⁹⁷ the vast majority of whom lives in rural farming areas of lower and middle income countries. Hundreds of thousands of people are affected by groundwater arsenic contamination in Bangladesh and India,¹⁴⁹ and outbreaks of poisoning from contaminated food⁴⁰ and environmental pollution from poorly regulated industrial activity^49,135 affect whole communities throughout the developing world.

The resources for dealing with these problems are limited in many countries. Public health education about poisons and infrastructure limiting access and exposure to the most highly toxic chemicals are practically absent in much of the developing world. Access to medical care is often limited for financial, cultural, and geographic reasons. Medical toxicology is frequently not a recognized specialty and patients are evaluated by general physicians with little training—although often with great experience. Diagnostic facilities are few, effective treatment options even more rare. Where antidotes exist, there is rarely enough knowledge or experience to use them effectively.³⁰ Intensive care beds for invasive monitoring and long-term ventilation are scarce. This chapter outlines some of the major poisoning risks and challenges for medical toxicology in the developing world.

POISONING AND THE GLOBAL BURDEN OF DISEASE

The World Health Organization (WHO) has ranked injury, including poisoning, among the top 15 causes of death worldwide for persons aged 5 to 44 years.^114,174 Recent reanalysis of data from the Global Burden of Disease project estimated that acute and chronic exposure to chemicals caused over 4.9 million deaths and 86 million disability-adjusted life years (DALYs) worldwide in 2004—more than cancer, sexually transmitted diseases, or diabetes.^135,179 Children younger than 15 years of age bore more than one half of this burden.

Tremendous regional disparities in the health impact of poisoning are apparent. The global mortality burden from poisoning is disproportionately shouldered by lower and middle income countries. Overall, as much as 75% or more of all poisoning related deaths occur in the developing world,⁸¹ and an estimated 95% of children who die each year from acute poisoning live in low- and middle-income countries.¹⁷⁴ Children living in Sub-Saharan Africa are at highest risk, with an estimated annual mortality rate of four children per 100,000 population. This is double the global average and higher than that in any other region.¹⁴²

These figures are striking, yet most likely underestimate the contribution of poisoning to the global burden of disease and disability. Much of the existing data on poisoning epidemiology from lower income countries reflects the experience in larger hospital centers. By contrast, most of the population lives in rural areas, and many patients with poisoning may never reach such facilities for a variety of financial, cultural, or geographic reasons. For example, logistical difficulty with accessing health care facilities was responsible in part for the high mortality from snakebite noted in one community-based study in Nepal.¹⁴⁶ Social or economic barriers often contribute to “healer shopping” within traditional or spiritual systems, with allopathic medical care delayed or avoided in many African countries.^52,86,128

Unintentional poisoning risks from occupational, environmental, food, or medication sources may also be poorly recognized in commu­nities, or by health care workers.¹²³ The diagnosis of poisoning may not be suspected if a clear history of exposure is not given, because symptoms can mimic infectious or other processes and few medical centers have ready access to laboratory tests for specific poisons. When poisoning is suspect, many countries lack detailed injury surveillance systems or other standardized reporting mechanisms. The WHO has undertaken several initiatives to improve global poisoning surveillance, including support for poison center (PC) development in under represented regions worldwide, and the international efforts of the IPCS/INTOX programs to harmonize data collection and reporting terminology represent an important step toward this goal. However, the interpretation of PC data as evidence of epidemiologic trends must be approached with some caution (Chap. 136).

COMMON XENOBIOTICS AND PATTERNS OF POISONING

Agents commonly involved in acute poisoning differ substantially between communities, both within and among countries. For example, a comparison of poisoning cases seen at a major public teaching hospital in New York City with two large rural hospitals in Sri Lanka found striking differences in the classes of xenobiotics involved. A total of 70% of the patients in New York City were poisoned with pharmaceuticals, and 90% of patients in the Sri Lankan cohort were poisoned with nonpharmaceuticals, primarily pesticides and botanicals, such as yellow oleander, with a 10 times higher case fatality rate.⁸¹ A study comparing poisoning epidemiology in district (rural) and regional (urban) hospitals in Zimbabwe found that poisoning from pesticides was equally common in both settings, but animal envenomation was seen nearly twice as often at the district facilities compared to regional centers, and poisoning with pharmaceuticals was a problem seen uniquely at the regional hospital.¹⁵⁶

Understanding the local patterns and specific risks for poisoning in particular communities is of critical importance since it provides an evidence base for designing and prioritizing strategies to prevent or limit harm. This section reviews some of the more common xenobiotics implicated in poisoning in developing countries worldwide.

Pesticides

A systematic review suggested that at least 250,000—but more likely 350,000—deaths occur each year from acute pesticide self-poisoning around the world.⁷² The WHO now considers pesticide poisoning to be the single most important means of suicide, accounting for more than one-third of all suicides worldwide.²⁵ Most of these deaths occur in Asia, particularly in China and India.⁷² The annual number of deaths from occupational or unintentional pesticide poisoning is unknown but was estimated 20 years ago at 20,000.⁹⁰

While many classes of pesticides are implicated (Chap. 113), organic phosphorous (OP) pesticides appear to be responsible for the majority of pesticide-related deaths in the developing world.⁵⁶ Deliberate self-poisoning with OP pesticides puts a high cost on the health care system. In one study examining the experience in Sri Lanka, OP pesticide poisoning was responsible for 943 of 2559 (36%) admissions to a secondary hospital for poisoning.⁶⁰ The case fatality for OP poisoning was 21%, and pesticide poisoned patients occupied 41% of all medical intensive care beds. Similar situations have been reported from across the world.⁵⁶ In all likelihood, such studies underestimate the mortality associated with intentional pesticide ingestion as most are hospital based and do not include patients who die prior to hospital presentation.²

Factors contributing to the high mortality of self-poisoning with pesticides in the developing world include the intrinsic lethality of many pesticides, and health care systems that are poorly prepared to handle such critically ill patients (Table 137–1). Pesticides are often easily available in highly concentrated preparations in rural communities throughout the developing world. The ease of drinking liquid pesticides is also a factor facilitating massive intentional ingestions, as are inadequate pesticide storage systems.⁹⁹ Outbreaks of unintentional poisoning from contaminated flour or old pesticide containers used to store food still occur in rural areas.⁵⁴ The extraordinarily high human, economic, and social costs of pesticide-related mortality worldwide reinforce the importance of developing simple, economical, and evidence based strategies specifically designed to care for acutely poisoned patients in resource limited environments.^26,32

Envenomation

Envenomation by snakes and other animals represents another significant cause of morbidity and mortality in the developing world. Few countries mandate the reporting of animal bites, making it difficult to estimate global incidence, severity, and outcome. Current data estimates that about 20,000 to 94,000 deaths occur globally each year from snakebite.⁹⁷ The vast majority of deaths and serious envenomations occur in the developing world, with less than 100 snakebite deaths per year estimated to occur in Europe, the United States, Canada, and Australia combined.^42,97

Because most rural people in the developing world may first consult traditional healers, hospital based studies of mortality and morbidity associated with snakebites likely underestimate the scope of the problem.^42,150 For example, a study of rural Philippine rice farmers found that only 8% of cobra (Naja philippinensis) bite victims reached a hospital in the 1980s.¹⁷⁰ However, changes in treatment seeking can occur. Studies over the last decade in Sri Lanka have shown that patients have started going to the hospital rapidly after common krait (Bungarus caeruleus) snakebite, bypassing traditional healers.¹⁰³ A study in Ghana found that the incidence of snakebite victims at a district hospital increased significantly after the introduction of a new treatment protocol, possibly reflecting increased confidence in the ability of the health care system to manage these cases.¹⁶⁸

Snakebites are most commonly occupational hazards in the rural tropics. Victims are just as likely to be women as men, reflecting rural farming practices. Working in large plantations and subsistence farms places rural people in frequent contact with venomous snakes. With simultaneous changes in global climate and expansion of human settlements, it is likely that the range of venomous snakes will enlarge to include urban areas and regions previously considered too temperate to support them.^82,121 Snakebites from members of the Elapidae and Viperidae families are responsible for the majority of deaths worldwide, although several other families are also medically important (Colubridae and Atractaspididae species, in particular; Chap. 122 and Special Considerations: SC8).^169,172

The burden of snake envenomation on local resources can be substantial. During the rainy season in Benin, snakebites account for up to 20% of all hospital admissions, with an estimated case fatality rate of 3% to 6%.⁴³ In this region, the annual incidence of snake envenomation ranges from 200 to 100,000 in rural villagers to 1300 to 100,000 in sugar cane plantation workers.⁴³ One study conducted in Nigeria in the late 1970s noted an incidence of 497 per 100,000 and a 12% case fatality (primarily due to envenomation by the carpet viper, Echis occelatus).¹³⁶

After snakebites, the second most common cause of mortality and morbidity from venomous animals is scorpion stings^88,169 (Chap. 118). Medically important scorpion species are widely distributed throughout the tropics, being particularly common causes of morbidity in North Africa, Mexico, India, and Brazil.⁴⁴ The total number of medically significant ­scorpion stings that occurs annually is unknown; a recent review estimated 1.2 million stings, leading to more than 3250 deaths (case fatality 0.27%).⁴⁴ Other venomous insects, such as Arachnida (spiders) and Hymenoptera (bees, ants, and wasps), are rarely sources of significant mortality on a global scale⁸⁸ (Chap. 118).

Herbal and Traditional Medicines

The use of traditional medicine (TM) to treat or prevent health problems is widespread. The WHO estimates that around 80% of the world’s population consults traditional healers regularly.¹⁷⁷ Frequently cited reasons for this preference or reliance on TM include financial considerations, sociocultural preferences, beliefs about the relative safety and efficacy of TM compared to allopathic medicines, and mistrust or relative inaccessibility of doctors.^86,128 Traditional practitioners still greatly outnumber medical professionals in many regions. For example, in 2004 there was one traditional healer but only 0.04 physicians per 500 inhabitants in Mali.⁷¹

Although TM also encompasses a variety of spiritual, religious, or physical manipulation therapies, it often includes administration of “herbal” remedies (muti) either orally or via enema. These are typically prepared using a combination of aqueous plant materials, sometimes mixed with insect or other animal parts, metallic salts, or both. While traditional medicinal preparations have usually been tested by generations of practitioners and the concentrations of active ingredients are generally low, both intentional and unintentional poisonings are common.^{38,94,153,157} In a 2-year retrospective review of acutely poisoned patients from South Africa, TM was the second most common cause of admission (15.8% of cases) and had the highest mortality rate (15.2%), accounting for over half of all deaths in the series.¹⁶⁷ TM was the most common cause of admission (23% of cases) for acute poisoning in another 10-year retrospective review of cases from Zimbabwe, with a 6% mortality rate.⁹⁵

The specific chemical constituents responsible for TM poisoning may vary widely between geographic and cultural areas. Laboratory analysis and ethnopharmacologic surveys in a number of countries have begun to elucidate some of the chemical constituents of commonly prescribed recipes. Interestingly, a review of 41 autopsies in South Africa for which the causative agent was presumed to be an herbal medicine found that cardiac glycosides were present in 44% of cases.¹⁰⁹ Adulterants are also implicated in poisoning from TM formulations. For example, these are common in traditional Ayurvedic medicines (particularly heavy metals⁶³ and corticosteroids⁷⁵) and Asian medicines (particularly synthetic pharmaceuticals and heavy metals³⁶ Chap. 45). A Taiwanese study of 2609 samples found that 23% were adulterated with pharmaceutical products such as caffeine, NSAIDs, acetaminophen, and diuretics.⁸⁴

Pharmaceuticals

In many lower income countries, pharmaceuticals are relatively uncommon causes of acute poisoning. However, the incidence appears to be rising in conjunction with larger global demographic shifts toward increased urbanization and industrialization. Access to a wider array of medications is relatively greater among urban dwellers than in rural ones, and more people in urban communities may have the financial means to buy them. In a retrospective review of poisoning cases admitted to urban versus rural health centers in Zimbabwe, poisoning with pharmaceuticals was uniquely seen at the urban facilities, accounting for more than 15% of poisoning cases at regional hospitals surveyed and none of the cases presenting for care at the district level.¹⁵⁶ The relative importance of pharmaceuticals in global poisoning trends is likely to continue over the next decades as the number of therapeutic drugs available for use in lower income countries expands, and more and more societies shift toward a “dual burden of disease” pattern, including chronic illnesses that require long-term drug therapy.^21,120

The pharmacopeia available in low-income countries is often more restricted than in higher income countries, and this is reflected in the types of medications implicated in acute poisoning cases. The most common xenobiotics seen in the developing world are those used to treat tropical diseases. For example, self-poisoning with the antimalarial chloroquine (Chap. 59) has been widely reported in Sub-Saharan Africa,^{20,27,116,137} although this medication is now rarely used so the incidence may soon decrease. Intentional and unintentional poisoning with the leprosy drug dapsone, as well as the tuberculosis drug isoniazid (Chap. 58), are also well reported.^{132,158,159,165}

Criminal poisoning of commuters to facilitate robbery is a common problem across South Asia.^89,117,133 In the 1970s and 1980s, drinks containing extracts of Datura stramonium were given to unsuspecting commuters, resulting in anticholinergic poisoning.⁹⁸ Practice has changed recently and benzodiazepines are now more commonly given for this purpose.¹⁰⁸ As many as 300 people are admitted unconscious with this problem to a single university medical unit in Dhaka each year.¹⁰⁸

A more general issue of toxicologic concern is the prevalence of poor-quality medicines in use worldwide. Although data estimating the extent of the problem and its impact on health are limited, recent estimates suggest that more than one-third of all medicines on sale in Southeast Asia and Sub-Saharan Africa are substandard or counterfeit.^23,118,119 The major problem with these medications is an absence or subtherapeutic concentration of active ingredient, leading to treatment failures and an increase in drug-resistant pathogens where antimicrobials are involved. However, substandard medications may sometimes contain more active ingredient than stated, leading to adverse drug effects,¹⁶¹ or contain harmful adulterants or contaminants.

Epidemic poisonings from such poor quality medicines underscore the dangers of inadequate regulation and oversight of pharmaceutical manufacture and sales. Recent examples include the deaths of more than 120 patients in Karachi from exposure to a batch of isosorbide mononitrate contaminated with pyrimethamine,¹⁵ the hospitalization of more than 50,000 infants in China with melamine poisoning from adulterated formula,⁸⁷ and the numerous epidemics of diethylene glycol poisoning in multiple countries over the past few decades from contaminated glycerine, paracetamol syrups, cough syrups, toothpastes, teething mixtures, and other medications.^{22,79,125,127,140,148}

Household Products and Chemicals

Poisoning with common household products, such as fuels, cleansing products, rat poisons, insecticides, body care products, and cosmetics, is a global problem. This general category of diverse xenobiotics is consistently implicated as a significant source of unintentional childhood poisoning worldwide. The PC movement that began in the 1950s in North America grew out of an increasing recognition of the child health risks associated with exploratory household poison ingestions. Household chemicals are a similarly well recognized risk for unintentional childhood poisoning in Sub-Saharan Africa, accounting for up to 80% of all pediatric admissions for poisoning.^{21,41,45,96,126} Internationally, the specific risks are remarkably consistent, including age younger than 6 years (with toddlers younger than 3 years of age most affected), male sex, low socioeconomic status, and unsafe storage practices in the home.

Among specific household products, hydrocarbon poisoning from unintentional ingestion of kerosene (paraffin) is widely reported as the most common cause of pediatric admissions in low-income countries around the world.^{41,45,96,102,173} Kerosene is a common fuel used to power stoves and lamps in many relatively poor communities. It is pale in color with an appearance similar to water, and it is often purchased or stored in used beverage containers making it easy to misidentify (Chap. 108).⁶² In Sub-Saharan Africa, kerosene poisoning accounts for some 25% to 75% of all poisoning-related hospital visits among children younger than 6 years of age.¹²² Several studies document an increase in poisoning related admissions during the warmer months of the year, when children are more likely to become thirsty and to drink from any beverage container at hand.^101,102

Caustics are another group of household products frequently implicated in poisoning in the developing world. The common form of caustic ingested varies between countries. In many countries, alkaline substances are most frequently implicated, whereas in others, such as Taiwan and Morocco, poisoning with hydrochloric or sulfuric acids may be more common.^{3,105,154,180} Acute poisoning carries substantial mortality risk, usually more than 10%. If the acute phase of caustic poisoning is survived, there also is a high rate of delayed complications, primarily esophageal strictures. Delayed complications may require surgical intervention, balloon dilatation of the esophagus (bougienage), or feeding tube placement. These treatments are expensive, require significant hospital resources, and have inherent morbidity and mortality (Chap. 106).

As with other categories of poison, patterns of self-harm using domestic products tend to demonstrate regional particularities. For example, in Hong Kong there is significant morbidity reported in association with self-poisoning using common household detergent products such as dettol (4.8% chloroxylenol, pine oil, and isopropyl alcohol) and savlon (cetrimide).^34,37,39,46 Frequent use of potassium permanganate for self-harm has also been reported from Hong Kong.^129,181 Fatal poisoning with hair dye (paraphenylenediamine) is known in the Middle East and North Africa.^29,61,80,151 Barium sulfide, arsenic sulfide, and calcium oxide are contained in hair removal preparations¹⁴⁶; poisoning from ingestion of these preparations has been reported from India and Iran.⁴ Rubigine is a domestic cleansing product containing hydrofluoric acid and ammonium difluoride that is used for self-harm in the Caribbean,⁸⁵ while ingestion of sodium hydroxide is common in Malaysia.¹⁹

Plants

Poisonous plants have been used therapeutically to induce abortion, for recreational intoxication, in homicidal acts, and for self-harm throughout human history (Chap. 121). This section briefly mentions select toxic plants that are most commonly used in self-poisoning, or that have caused epidemic poisoning in the developing world.

Self-poisoning with seeds of two plants containing cardioactive steroids are important clinical problems in Asia. Yellow oleander (Thevetia peruviana) kills hundreds of people each year in Sri Lanka and India^28,57 (Chap. 65). Sea mango (Cerbera manghas) has killed hundreds of people in Kerala, India,⁶⁸ and is a focal problem in eastern Sri Lanka.⁵⁸ Oduvan (Cleistanthus collinus) leaf contains the glycosides cleistanthin A and B, which produce severe hypokalemia and cardiac dysrhythmias.¹³ Self-poisoning has killed hundreds of people in Tamil Nadu, India.^12,155 The superb lily (Gloriosa superba) contains colchicine alkaloids and has also been used for self harm in South Asia^5,9,111 (Chap. 36).

Ackee tree fruit (Blighia sapida), which contains hypoglycin when unripe, is widely consumed as a food source. Epidemics of fatal poisoning with unripe Ackee fruit have occurred throughout the Caribbean and in Africa.^{64,92,110,112} Poisoning by castor beans (Ricinus communis) or other lectin containing plants such as Jatropha spp (African purging nut) is well reported from Africa and South Asia^1,65,78,93 (Chap. 121).

Numerous plant species contain atropine like alkaloids, causing an anticholinergic syndrome when ingested. Reports of intentional ingestion of Datura species have been reported from Africa, Asia, and Latin America.^78,143,152 Most commonly, the seeds are ingested as a recreational drug for their hallucinatory effects,^67,138 or as part of traditional medical preparations.³⁵

Occupational and Environmental Sources

Poisoning from occupational and environmental sources is a significant global health problem, with disproportionate effects on persons living in lower income communities around the world. Exposure to “traditional” environmental health hazards, such as indoor air pollution from the combustion of solid fuels, and naturally occurring contaminants in groundwater, soil, and food, is still a major cause of morbidity and mortality in much of the world. Around 50% of the world’s people rely on solid fuels such as coal, dung, wood, or crop residues for cooking and heating.³¹ Resultant indoor air pollution was estimated to cause 1,965,000 deaths and 41,009,000 DALYs from lower respiratory tract infections, cancers, and COPD in 2004.¹⁷⁸ In Bangladesh, arsenic contaminated groundwater contributed to 9100 deaths and 125,000 DALYs in 2001.¹⁰⁷ Dental and skeletal fluorosis from excessive fluoride in drinking water is endemic in at least 17 countries worldwide.⁶⁶

Increasingly, modern environmental health hazards (MEHHs) also play a large role in global poisoning risks.^49,124 MEHHs include outdoor air pollution from automobiles and factories, soil and water contamination by plastics, heavy metals, pesticides and other industrial chemicals and wastes, radiation hazards, land degradation, and climate change produced by rapid urbanization and industrial development in the absence of strong regulatory controls.⁴⁹ These are important sources of both occupational and environmental exposure to a wide range of toxins with acute and chronic health effects. Inadequate safeguards to control the selection, sale, and application of pesticides in parts of Africa and Asia are linked to pesticide poisoning both as an occupational hazard^53,91 and from residues left on food.^11,48,123 Occupational lead poisoning has largely been controlled in developed countries through improved working conditions and occupational health screens, but remains an enormous problem in developing countries where occupational and environmental health protection measures are often underdeveloped or practically nonexistent.^164,171

Industrial factories are often placed in urban areas, or the areas around factories are rapidly urbanized, placing large numbers of people at risk not only from pollution but from industrial errors as well. The 1984 Bhopal tragedy in which a Union Carbide pesticide plant malfunctioned, releasing isocyanate gas into the surrounding community and causing an estimated 3787 deaths and 558,125 injuries, is emblematic of such disasters.^14,145

Several international agreements on chemical safety provide legal frameworks to mitigate the human and environmental impact of global industrialization; however, the actual implementation of regulatory controls has lagged behind the expansion of toxic exposures. For example, at the level governance a total of 39 Sub-Saharan African countries have ratified the Rotterdam Convention on chemical safety. Yet industrial pollution is now becoming so highly concentrated in growing urban areas that the continent’s pollution intensity (pollution generated per unit of production output) is now rated among the world’s highest, attesting to significant regional difficulties in enforcing such regulations.¹⁶⁶

The predominance of informal sector activity in agricultural and industrial work in lower income countries poses serious regulatory challenges. Fumes and dusts from small-scale domestic businesses involved in smelting, battery recycling or manufacture, welding, pottery, ceramic production, and artisanal mining are common sources of exposure to lead and other heavy metals in developing countries, and put not only workers but whole communities at risk.¹⁶⁴ More recently, unregulated electronic waste (e-waste) recycling, in which salable metals are reclaimed from old electronics by burning, has emerged as a significant human and environmental health hazard in parts of China, West Africa, and India.^7,104,160 Workers are often aware of the health risks, yet economic hardship and lack of alternative employment make them unwilling or unable to change.

Easy access to industrial chemicals from inadequate regulation of packaging and sales may also facilitate their use for intentional self-harm. For example, formic and acetic acids are used in the manufacture of rubber, and case series are reported from areas surrounding rubber factories in India and Sri Lanka.¹³⁹ Copper sulfate is widely used for self-poisoning in parts of South Asia, and carries a high mortality rate due to direct damage to the gastrointestinal tract, hepatorenal failure, and hemolysis^6,144 (Chap. 95). Cyanide has become a commonly used method in Korea over the last 20 years¹⁰⁶ (Chap. 126).

REDUCING THE GLOBAL IMPACT OF POISONING

Regulatory science and the coordinated actions of agencies and programs across multiple sectors play a vital role in preventing or reducing the impact of poisoning in society. Within the health sector, significant inter- and intraregional disparities in access to health care have a major impact on poisoning outcomes. Lack of human resources to provide acute care is an enormous problem in many parts of the developing world. In Mozambique, there is only one trained medical doctor for every 33,000 individuals, compared with 1 in 390 persons in the United States. Tanzania has a nurse to population ratio of 1:2700 individuals compared with 1:107 individuals in the United States. Policies and programs encouraging sustainable and equitable health workforce development are needed foundation to improve health care access globally.⁵⁰

Beyond rectifying the raw numbers deficit, clinical training programs in many low and middle income countries must be upgraded to promote broad exposure and specialist development in clinical toxicology and acute care. Increasing local and international commitment to the growth of emergency medicine in low- and middle-income countries promises to support the dissemination of scientific knowledge and improve provider competence in advanced resuscitation techniques.^8,16,70 Significant gaps in infrastructure and resources to provide basic critical care interventions and meet WHO minimum standards for essential emergency supplies must also be addressed.^17,18,83

In addition to global disparities in acute care infrastructure generally, access to antidotes for specific poisons is either lacking or inadequate in much of the world.^10,131,176 Poor antidote availability is not unique to the developing world,⁵¹ and many antidotes may be considered either adjunctive or unnecessary therapies. However, in certain cases they can significantly reduce the need for other medical interventions, and this may be particularly important in rural or underdeveloped areas where critical care facilities are not readily available.¹³⁴ For example, the most important challenge to improving the treatment of patients with snakebite worldwide is poor antivenom availability, particularly in rural areas where it is most needed to reduce critical delays in administration.^162,163 Currently, many available antivenoms are prohibitively expensive, ineffective, or have a high rate of adverse reactions. Equally important, some antivenoms must be refrigerated, making storage impractical in many rural areas where the need is most acute. Critical evaluation of existing antivenoms and development of new products are thus desperately needed^{24,30,76,77,105,162,163,172,175} (Special Considerations: SC8).

Where antidotes are available, knowledge and experience to know how to use them safely and effectively is often lacking.³² Input from experts in medical toxicology improves outcomes, reduces hospital stays and health care costs associated with acute poisoning,^33,47,69 but practitioners in many parts of the world have limited or no access to consultation with such specialists. The mission of the International Union of Toxicology is to foster international scientific cooperation, ensure the development of toxicologists, and promote the dissemination of knowledge in toxicology worldwide.⁵⁵ Through the collaborative efforts of this and other regional professional societies, an increasing number of online, regional, and international forums now offer educational and professional development opportunities in clinical toxicology around the globe. More work is needed to promote awareness and the growth of the specialty in all regions.

Improving health care access and health system preparedness is only one aspect of the coordinated, multilevel, national, and international public health responses needed to reduce the global impact of poisoning. Prevention and risk reduction efforts must involve locally appropriate community level education and awareness raising, strong governance to support the design, implementation, and monitoring of regulatory controls, and the involvement of multiple stakeholders and sectors including water, waste management, energy, agriculture, transportation, industry, and civil society. Effective legislative frameworks developed in countries with more advanced public health infrastructure have been successfully disseminated in some cases. For example, between 2000 and 2004 the proportion of people with blood lead concentrations above 10 μg/dL globally decreased from 20% to 14%, largely due to the widespread phase out of leaded gasoline.¹³⁵ Other strategies, such as pharmaceutical and food safety regulations enacted through the US Food and Drug Administration, have influenced “duplicative legislation” in other countries but continue to pose significant implementation challenges in low and middle income countries that lack the necessary financing, human resources, and infrastructure to enforce them well.¹³⁰

Many public health measures with proven efficacy, such as routine lead testing during childhood, the regulation of vehicle emissions, the detection of carbon monoxide, and the incorporation of childproof containers may seem prohibitively resource intensive in many parts of the world. The development of new, low-cost technologies such as solar heating and electrical sources, chemical assays and residue detectors, and electronic devices to identify and track pharmaceuticals hold some promise to reduce global risks for unintentional poisoning. More research is needed to propose and evaluate the effectiveness, acceptability, and sustainability of new and proven poison prevention techniques in resource-limited environments.

Recognizing that self-harm from pesticide ingestion is responsible for a majority of acute poisoning deaths worldwide, public health interventions specifically designed to limit access are an important goal. A minimum pesticide list, based on the WHO essential xenobiotic list initiative, has been proposed.⁵⁹ Such a list would provide policy makers and farmers with unbiased information about relative risks. However, voluntary initiatives such as international policy statements and industry sponsored programs often suffer from a lack of resources, a shortage of political will, and nonexistent enforcement mechanisms.^100,115 A dramatic illustration of an effective national program to reduce pesticide poisoning risks is the ban of all WHO high-risk OP insecticides and the organic chlorine endosulfan in Sri Lanka, which effectively arrested a previously exponential increase in the incidence of pesticide poisoning and halved the national suicide rate between 1995 and 2005.⁷³ This program is estimated to have saved more than 20,000 lives in 10 years.⁷³

Ironically, some programs to remove the most environmentally persistent and toxic chemicals from use have inadvertently replaced them with agents highly toxic to humans. The replacement of persistent organic chlorine compounds with carbamates in malaria control programs is an example. The opposite effect has also occurred, for example, by replacing OP insecticides with pyrethroids to reduce human toxicity.¹⁰⁰ Coordinated pesticide harm reduction strategies should take into account concerns regarding both environmental and human toxicity, and anticipate which xenobiotics will enter into use as replacements as specific chemicals are phased out.¹⁴¹ A strategy based on industrial hygiene models of a hierarchy of controls has been proposed by several authors^115,141

(Table 137–2).

SUMMARY

• Poisoning is a common worldwide. Fatal poisoning is disproportionately concentrated in lower and middle income countries, where public health systems and acute care resources to detect, manage, prevent, and collect data on poisoning are often less well developed.

• Global poisoning estimates are mostly derived from health care sources in a minority of developing world countries; current data may underrepresent the true burden and distribution of injuries from poisoning.

• Efforts to develop international poisoning surveillance systems and establish harmonized definitions of poisoning cases will help generate a more complete picture to inform local, national, and international policies and interventions.

• Pesticides are the most important cause of death from acute poisoning worldwide, with a majority of cases attributable to acts of deliberate self harm.

• Improving access to health care and health system preparedness to provide acute care is essential to reduce global disparities in poisoning outcomes.

• Randomized controlled trials and cost effectiveness research are needed to critically evaluate the utility of specific public health and treatment interventions in resource limited settings.

Acknowledgments

Michael Eddleston, MD, and Aaron Hexdall, MD, contributed to this chapter in previous editions.

References

Principles of Epidemiology and Research Design

INTRODUCTION

Advances in medical toxicology are achieved through the scientific method using observations, derived from cases of poisoning and nonpoisoning due to xenobiotic exposures, to generate hypotheses. Subsequent research questions are analyzed with epidemiological investigation, and preliminary studies are examined with methodological scrutiny. Initial analytical techniques are improved, and confirmatory studies are performed. Ultimately, models relating cause to effect are formulated.

To optimize patient care, it is useful to grade the quality of available scientific evidence used to justify treatment recommendations. Decisions about how strongly to recommend a medical action will be based on the careful consideration of the risks of leaving a patient untreated, the potential benefits and harms of treatment, the quality of the guiding evidence, a balanced view of resource utilization, and the values of the person to be treated. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group has provided a framework for assessing and communicating levels of scientific evidence (Table 138–1).²² An understanding of basic principles of research design and epidemiology is required to interpret published studies and to lay the groundwork for future investigation in toxicology.

EPIDEMIOLOGIC TECHNIQUES AVAILABLE TO INVESTIGATE CLINICAL PROBLEMS

Table 138–2 lists the different study formats discussed below.

Observational Design: Descriptive

A staggering array of xenobiotics are able to injure people, necessitating reliance of toxicologists on good descriptive data regarding toxic outcomes. Through 2011, the National Poison Data System (NPDS) of the American Association of Poison Control Centers (AAPCC) has amassed a database of more than 50 million human exposures (Chap. 136). Descriptive case reporting serves a valuable purpose in describing the characteristics of a medical condition or procedure and remains a fundamental tool of epidemiological investigation. A case report is a clinical description of a single patient or procedure in a unique context. Case reports are most useful for hypothesis generation. However, single case reports are not always generalizable, as the reported situation may be atypical. A number of case reports can be grouped on the basis of similarities into a case series. Case series can be used to characterize an illness or syndrome, but without a control group they are severely limited in proving cause and effect. In 1966, a case series of two patients with acute liver necrosis following overdose of acetaminophen (APAP)¹² was accompanied by a case report of liver damage and impaired glucose tolerance after APAP overdose,⁴⁰ which led to further study and the eventual creation of the Rumack-Matthew nomogram (Chap. 35). Similarly, a 1979 case report of “hypertension and cerebral hemorrhage after trimolets ingestion”²⁴ led to subsequent animal studies, experimental human studies, and epidemiologic studies culminating in the decision by the US Food and Drug administration to remove phenylpropanolamine from nonprescription cold remedies and appetite suppressants (Chap. 42). The important role for descriptive data in guiding clinical research, focusing educational efforts, and formulating public policy are often underappreciated.

Cross-sectional studies assess a population for the presence or absence of an exposure and condition simultaneously. Such data often provide estimates of prevalence—the fraction of individuals in a population sharing a characteristic or condition at a point in time. These studies are particularly helpful in public health planning and have been extremely useful in monitoring common environmental exposures, such as childhood lead poisoning, or population-wide drug use, such as occurs with tobacco, marijuana, and alcohol. The US National Health and Nutrition Examination Survey demonstrated that the percentage of children with blood lead concentration greater than 10 μg/dL decreased from 88.2% to 4.4% between 1976 and 1991, with the highest rates of plumbism among African American, low-income, or urban children.⁵

An analysis of secular trend is a study type that compares changes in illness over time or geography to changes in risk factors (ecological). These analyses often lend circumstantial support to a hypothesis; however, because of the ecologic nature of their design, individual data on risk factors are not available to allow exclusion of alternative hypotheses also consistent with the data. A prime example of an analysis of secular trends is the finding that reports of Reye syndrome declined between 1980 and 1985, coincident with a fall in sales of, or physician recommendations of, children’s salicylate products.⁴ This investigation suggested an etiologic role of salicylate in the development of Reye syndrome but could not exclude alternative hypotheses such as a change in viral epidemic patterns.

Observational Design: Analytical

Hypotheses that are generated by theoretical reasoning or anecdotal association require analytical testing. Case-control studies and cohort studies are analytical techniques that use observational data, and each technique has its own advantages and disadvantages (Table 138–2). Case-control studies compare affected, treated, or diseased patients (cases) to nonaffected patients (controls) and evaluate for a difference in prior risk factors or exposures (Fig. 138–1A). Because participants are recruited into the study based on prior presence or absence of a particular outcome, case-control studies are always retrospective in nature. They are especially useful when the outcome being studied is rare, and they enable the investigation of any number of potential etiologies for a single disease.

The hypothesis, derived from multiple case reports and case series, that phenylpropanolamine might increase risk for hemorrhagic stroke was well suited to case-control study. Exposure to ingested phenylpropanolamine, as an ingredient in cold remedies and appetite suppressants, was common; but hemorrhagic stroke is rare among children and young adults. Other putative risk factors such as tobacco use, hypertension history, family history, cocaine use, and contraceptive use were identifiable and could be studied simultaneously. In a case-control analysis of 702 participants with hemorrhagic stroke and 1376 controls, the use of appetite-suppressant doses of phenylpropanolamine were found to be independently associated with the occurrence of hemorrhagic stroke.²³

Cohort studies compare patients with certain risk factors or exposures to those patients without the exposure, and then follow these cohorts to see which participants develop the outcome of interest (Fig. 138–1B). In this respect, they allow the comparison of incidence (the number of new outcomes occurring within a population initially free of disease over a period of time) between populations who share an exposure and populations who do not. They may be retrospective or prospective and enable the study of any number of outcomes from a single exposure. They are particularly well suited to investigations in which the outcome of interest is relatively common. In circumstances when an outcome of interest is very uncommon, such as the case with stroke after phenylpropanolamine use, the large number of study participants required might make a cohort study impractical. A cohort of 981 APAP overdose participants was used retrospectively to investigate whether administration of activated charcoal might be beneficial therapy for APAP poisoning.⁸ Participants were separated on the basis of whether or not they were treated with activated charcoal and were subsequently followed to see if they developed concentrations deemed toxic by the Rumack-Matthew nomogram. Perhaps the most famous cohort study was the Framingham Heart Study in which 5209 residents of Framingham, MA, aged 30 to 62 years, were followed for over 50 years. This study provided a useful tool for studying the incidence of lung cancer, stroke, and cardiovascular disease in those exposed to cigarette smoke and other hazardous xenobiotics.¹³

Experimental Design

Experimental studies are those in which the treatment, risk factor, or exposure of interest can be controlled by the investigator to study differences in outcome between the groups (Fig. 138–2). The prototype is the randomized, blinded, controlled clinical trial. Among epidemiologic study types, these provide the most convincing demonstration of causality. Clinical trials are used to measure the efficacy (the treatment effect within a controlled experimental setting) of treatment regimens and to draw inferences about the effectiveness of a treatment applied to the general population. Sometimes a trial can be designed to study drug treatments that are hampered by nonresponders to therapy, expensive drugs, or poorly tolerated regimens. Such trials are termed noninferiority trials, and operate on the null hypothesis that the new (study) drug is worse than the control (standard) drug. Thus, finding a difference between groups in a noninferiority trial means that the alternative hypothesis can be accepted that the new drug is not worse than the standard treatment.

Unfortunately, interventional studies are the most complex to perform, and several questions must be addressed by investigators before performing a clinical trial (Table 138–3). Human clinical trials have been especially difficult to apply to the practice of toxicology. Table 138–4 lists characteristics of poisoned patients, which hamper attempts at clinical trials. Volunteer studies, using nontoxic xenobiotics or nontoxic doses of toxic xenobiotics, are often used to circumvent many of the problems in controlling human poisoning studies; but it is typically difficult to apply results from these studies to the actual context of toxic overdoses. In an experimental, human volunteer study, activated charcoal reduced absorption of ampicillin by 57%.³⁹ Taken out of this artificial setting, a trial of single-dose oral activated charcoal was unable to prove benefit to outcome among 1479 heterogenous participants presenting to an emergency department (ED) for possible poisoning.²⁹ Neither study was able to answer whether activated charcoal reduces morbidity from ingestion of dangerous xenobiotics if given while the xenobiotic is still in the stomach and amenable to adsorption.