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Relevant history depends on age of the patient and the underlying health of the child. Many complaints are nonspecific (e.g., cough and fever) and are common to both upper and lower respiratory tract disease. The predictive value of specific signs and symptoms is discussed below (see "Physical Examination" section).
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Ask about the presence, timing, and duration of cough, fever, rapid breathing, and difficult breathing. Ask about specific exposures, sick contacts, travel, and pets, when relevant.
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Choking or persistent or recurrent lower respiratory tract symptoms suggest foreign body aspiration. Recurrent pneumonias may signify underlying disease such as cystic fibrosis, immune disorders, or anatomic abnormalities.
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In young children, abdominal pain may be a clue to lower lobe pneumonia or effusion.
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Fever is a common but nonspecific sign of both upper and lower respiratory tract infections.
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Because neonates may acquire infections perinatally, be sure to ask questions about the mother's prenatal and perinatal health, including maternal infections (e.g., chlamydia, gonorrhea, group B streptococci, genital herpes, and human immunodeficiency virus status), intrapartum or postpartum fever, and any specific antibiotic or antiviral therapy received during labor and delivery. Other perinatal risk factors include prolonged rupture of membranes, prematurity, and immediate peripartum complications. Meconium aspiration may cause chemical or bacterial pneumonia in the first 24 to 72 hours of life. Neonatal stays in hospital suggest an underlying health problem and also increase the risk of nosocomial infection.
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Ask about the child's hospitalizations since birth and major illnesses, especially chronic respiratory problems (e.g., asthma, recurrent wheezing). In the young child, consider an undiagnosed respiratory, cardiac, renal, or immune dysfunction. Children with congenital respiratory problems (e.g., cystic fibrosis, neuromuscular disorders, immune compromise) are at increased risk of infection with common and rare agents, respiratory failure, and treatment failure. Adjust treatment and disposition accordingly (see Table 125-4).
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Take a brief, focused social history, because it may influence both diagnosis and treatment. For example, children from the far north, Native reserves, or countries with high rates of tuberculosis may be exposed to this uncommon but serious infection. A travel history may also be relevant. Children born to human immunodeficiency virus–positive mothers are at risk of vertical transmission and immunocompromise. Social history may also influence treatment decisions. For outpatient management, make sure that caregivers understand instructions, can afford medication, and can provide the required care (see "Disposition and Follow-Up" section below).
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Always inquire about childhood immunizations, and review records for confirmation when possible. Table 106-4 in chapter titled Emergency Care of Children provides a typical childhood immunization schedule. Ensure that enough time has elapsed to develop protective antibodies—typically 4 to 6 weeks for primary vaccination and 1 week for a booster. An unvaccinated child is at risk of serious morbidity, and even death, from vaccine-preventable illness.
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Annual immunization against influenza is recommended for children ≥6 months of age and for those at high risk due to underlying health conditions. Influenza vaccine must be given annually to account for seasonal antigenic changes (see "Special Considerations" section below). Priority is given to children with asthma, cystic fibrosis, and other pulmonary diseases; those with significant cardiac, renal, and immune disorders; and those with diabetes. Caregivers and healthcare providers should also be immunized to avoid transmission to these at-risk children.18
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Around the globe, immunization against polio, pertussis, measles, and H. influenzae type b infection has significantly lowered the risk of pneumonias and respiratory failure associated with these diseases. In some cases, simple herd immunity has decreased the chances that a child will come into contact with these once-feared diseases, but sporadic outbreaks exist in nonimmunized populations.
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Immunization against varicella (chickenpox) should protect against the secondary pneumonias associated with this virus, although use of the vaccine is not yet universal. Similarly, the administration of the bacillus Calmette-Guérin vaccine to provide partial protection against certain forms of tuberculosis varies by state, province, and country.
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The introduction of a seven-strain pneumococcal conjugate vaccine (Prevnar®, PCV-7) in 2000 to 2001 led to dramatic decreases in invasive disease and modest but promising trends in the reduction of pneumococcal pneumonias, especially in children <2 years old.19,20 Early reports suggested a somewhat diminished impact in human immunodeficiency virus–positive children.21 Vaccine-specific serotypes are being replaced globally by nonvaccine strains, although newer PCV-10 and PCV-13 vaccines are expected to counteract some of this serotype substitution. Children who received the initial PCV-7 series should receive a booster with PCV-13 to gain additional immunity.19 Vaccine coverage is universal in Canada but varies by state and private insurance provider in the United States.
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The older 23-valent polysaccharide vaccine (Pneumovax®) is effective in children ≥2 years of age, and it should be confirmed that the vaccine has been given to children with sickle cell disease, those who have undergone splenectomy, and others at high risk for pneumococcal disease. A booster may be required.
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In the developing world where imaging equipment and laboratory tests are limited, the World Health Organization has proposed a diagnostic algorithm based entirely on the presence or absence of tachypnea, respiratory distress, and lower chest retractions or indrawing. Although physicians in industrialized nations have many tools at their disposal, the diagnosis of pneumonia can still be made clinically.
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Rapid respiratory rate is a simple, standardized screening tool for pneumonia4 (Table 125-3).
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Children at very high altitudes may have a resting respiratory rate higher than children at sea level do, so oxygen saturation may be a more useful measure. Note that children who are severely malnourished or dehydrated or have impending respiratory failure may not be capable of generating rapid respiratory rates.
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Markers of respiratory distress include nasal flaring, tracheal tug, and intercostal indrawing. Lower chest or "abdominal" indrawing or retractions and grunting suggest more severe pneumonia.25 In infants, intermittent apnea, grunting, and an inability to feed are surrogate markers of dyspnea. Cough is less common in neonates or very young children, and productive cough is rarely seen before late childhood.
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Document oxygen saturation, because hypoxia on room air (arterial oxygen saturation <93% at sea level) increases the risk of oral amoxicillin treatment failure in severe pneumonia,26 and oxygen saturation <93% is a strong independent predictor of radiographic pneumonia.27
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Auscultate the chest using an appropriately sized stethoscope with the chest fully exposed, assessing all lung zones. Localized fine crackles (rales), coarse breath sounds (rhonchi), or diminished breath sounds suggest pneumonia, but sound recognition may not be consistent across observers23; a toxic appearance and overall impression of illness as judged by the clinician show better diagnostic sensitivity than focal auscultatory findings.4
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No single physical finding in isolation is diagnostic of pneumonia, and constellations of signs are more useful. For example, the combination of fever plus either tachypnea, decreased breath sounds, or fine crackles predicts x-ray–positive pneumonia with a sensitivity of 93% to 96%. The presence of fever plus all three of the other variables raises sensitivity to 98%, so much so that a radiograph is not required to make the diagnosis.28
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Conversely, a small but frequently cited study confirms that the child without tachypnea, respiratory distress, rales, and decreased breath sounds does not have pneumonia; a radiograph is not indicated.29
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Presumptive diagnosis of the causative organism and empiric treatment are made by considering historical and social factors (see above), immunization status (see above), and age of the child. See Table 125-4 for the most common causes of pneumonia by age as well as their treatment. Use care when assessing children with incomplete or no immunizations. Such children may be partially or fully susceptible to pneumonia associated with B. pertussis, H. influenzae type b, and all strains of pneumococcus, as well as measles, influenza, and varicella-zoster viruses.
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LABORATORY EVALUATION
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Because the results of most laboratory investigations are not known in the ED, tests are usually initiated to guide future treatment, except for rapid bedside tests for specific respiratory viruses. Nasopharyngeal assays for respiratory syncytial virus, influenza, and human metapneumovirus can be valuable, because they are quick and specific and results may negate the need for imaging, invasive testing, and antibiotic therapy. One may also defer imaging and antibiotic treatment for nontoxic children with clinical bronchiolitis or influenza, especially those with a positive nasopharyngeal swab finding.3,22
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Bacterial cultures of nasopharyngeal samples are generally not helpful, because results are delayed and oral flora correspond poorly with the organisms causing disease in the lung. The majority of newer serologic and polymerase chain reaction techniques to detect organisms such as H. influenzae or C. pneumoniae have not been validated in children and have produced variable results.3,5,22
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The routine collection of blood cultures is not recommended in healthy children with mild community-acquired pneumonia.22 For toxic-appearing children and those with severe disease requiring hospitalization, obtain blood for culture, CBC, electrolytes, and renal and hepatic function. Currently, the literature does not support the routine use of inflammatory markers (C-reactive protein or erythrocyte sedimentation rate), acute-phase reactants, or procalcitonin to distinguish bacterial from viral pneumonia in children.22
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When tuberculosis is suspected, obtain induced sputum samples from older children or gastric aspirates from infants for microscopy and confirmatory culture.30 These tests require equipment and expertise beyond the scope of the ED.
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Guidelines on the use of routine chest radiography are inconsistent.3,22,31 Consider chest radiographs only when the results are likely to alter diagnosis, treatment, or outcome.
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Benefits of radiography include diagnosis or confirmation of pneumonia and occasionally the discovery of a significant congenital abnormality. Risks and disadvantages include cost, delay, repeated exposure to ionizing radiation, and overdiagnosis of bacterial pneumonia.32 Several studies and major guidelines state that imaging should not be performed routinely in children with mild, uncomplicated acute lower respiratory tract infections.3,22,33,34 Most of these studies and guidelines reference outpatient settings, in which children with prolonged cough, severe symptoms, and other "red flag" features were excluded, so these recommendations may not apply to the ED setting.
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The chest radiograph is not the gold standard of diagnosis, because it is neither 100% sensitive nor 100% specific35 and may be falsely negative (e.g., when clinical disease precedes radiographic changes) or falsely positive (e.g., poor inspiration or rotation; Figures 125-1 and 125-2). Chest radiographs do not reliably distinguish between bacterial and viral causes.36,37 Young children with straightforward viral bronchiolitis may show radiographic areas of atelectasis or patchy collapse, resulting in a temptation to initiate antibiotic therapy for viral disease.
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Although routine radiographs are not usually necessary, potential indications for chest radiography are listed below:8,38,39,40
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Infants and children with a toxic appearance and respiratory findings
Age of 0 to 3 months with fever, as part of a full sepsis evaluation
Child <5 years old, with a temperature of >39°C (102.2°F), WBC of ≥20,000/mm3, and no clear source of infection
Suspicion of a complication, such as pleural effusion or pneumothorax
Pneumonia that is prolonged or unresponsive to treatment
Children with biphasic illness (typical symptoms of upper respiratory tract infection followed by acute worsening of [respiratory] symptoms and high fever)
Suspected foreign body aspiration
Suspected congenital lung malformation (e.g., sequestration or congenital cystic adenomatous malformation)
Follow-up of "round pneumonia" (see Figure 125-5) to exclude an underlying mass
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For a brief overview of important normal and abnormal radiographic findings unique to children, see the "The Pediatric Chest Radiograph" section at the end of this chapter.