INTRODUCTION AND EPIDEMIOLOGY
In 2015, multiple groups estimated that a quarter of a million people, approximately 5% of the adult population, used illicit drugs of any variety at least once; the expected use likely causes between 12 million and 28 million years of “healthy life” lost due to premature disability and death.1 In 2015, the United States had approximately one quarter of reported drug-related deaths worldwide, with more than double the death rate seen in 1999. Globally, drug-related deaths produced more mortality than road traffic accidents or violence. Opioids remain the most harmful type of drug of abuse, with a higher risk of fatal and nonfatal overdose and risk of acquiring infection. Of people who inject illicit drugs worldwide, about 1.6 million are infected with human immunodeficiency virus (HIV) and 6.1 million are infected with hepatitis C.
RISK BEHAVIORS OF INJECTION DRUG USERS
The practice of injection and the lifestyle and culture of injection drug users place such individuals at risk for a wide variety of infectious and noninfectious medical complications. In addition to carrying an increased risk of infection with HIV, hepatitis B and C, Kaposi’s sarcoma-associated herpes virus, tetanus, tuberculosis, and sexually transmitted diseases, the injection drug user also has an increased risk of trauma and intimate partner violence.2,3 It is important to vaccinate injection drug users against hepatitis B virus, human papillomavirus, and, when it becomes available, HIV.4 The Centers for Disease Control and Prevention recommends routine HIV screening in EDs and that consent for testing should be “opt-out.”5
An association between childhood emotional, physical, and sexual abuse or trauma and IV drug abuse also highlights the importance of trauma-informed interventions for injection drug users and the importance of early screening and treatment for drug abuse in those who have undergone childhood trauma.6 The high incidence of migration, incarceration, homelessness, nutritional deficiencies, coincident smoking and alcohol use, and mental illness further compromises the health of this group.
Injection drug use increases the risk for immunomodulating infections, such as HIV infection and hepatitis, and may induce immune dysregulation. Exaggerated and atypical lymphocytosis, diminished lymphocyte responsiveness to mitogenic stimulation and depressed chemotaxis, hypergammaglobulinemia, increased opsonin production, decreased T-cell and natural killer cell activity, high levels of circulating immune complexes, and reticuloendothelial abnormalities can be evident with ongoing drug injection. False-positive results on nontreponemal syphilis serologic tests, positive results on Coombs tests, low measured antibody response to vaccination, and thrombotic thrombocytopenic purpura are possible in this population.7 The immunomodulatory effects of injection drug use may also contribute to the progression of HIV infection, as HIV-infected patients who inject drugs are found to be less likely to suppress HIV-1 RNA than those who do not.8 Given their immune dysfunction, suspect infection in all febrile patients with ongoing drug injection even if the temperature elevation ...