Endocarditis Endocarditis is an infection of cardiac valves most commonly caused by S aureus, viridans streptococci, the socalled HACEK organisms (Haemophilus noninfluenzae species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae ), and Coxiella (Q-fever) Endocarditis is more common in children with existing structural heart disease The most common symptoms are fever, chills, fatigue, myalgias, and examination findings may include evidence of embolic phenomenon (pulmonary infarcts, intracranial or subconjunctival hemorrhages), Janeway lesions (nontender hemorrhagic macules on palms/soles), immunologic phenomenon (glomerulonephritis, Osler nodes [red, tender raised lesions on palms/soles], or Roth spots [white-centered retinal hemorrhages]) The diagnosis is based on the modified Duke criteria, which combine major criteria (blood culture positivity with an organism known to cause endocarditis; echocardiogram findings) with minor criteria, which include predisposing structural heart disease, fever, and embolic or immunologic phenomenon ED-based diagnosis involves obtaining several large-volume blood cultures before antibiotics are initiated to optimize culture yield The laboratory should be instructed to hold the blood cultures for several weeks, as some of the organisms causing endocarditis are fastidious Empiric management in the critically ill child with suspected endocarditis should cover MRSA and gram-negative organisms (e.g., with bactericidal antibiotics such as vancomycin and cefotaxime) Standard precautions should be used Myocarditis Myocarditis is a variably painful inflammation of the myocardium primarily caused by viral infections, most commonly enteroviruses, but parvovirus, influenza, parainfluenza, and adenovirus, and other viruses can also cause myocarditis In children with a consistent travel history, Chagas disease (Trypanosoma cruzi ) and parasitic infections can also cause myocarditis Myocarditis has been found in 15% to 20% of sudden infant death syndrome victims and the same proportion of adolescents who suffer from sudden cardiac death Early symptoms mimic the nonspecific findings of viral infections; the most common symptoms are shortness of breath, vomiting, poor feeding, rhinorrhea, and fever Chest pain is more commonly verbalized by older children The most common examination findings are tachypnea, hepatomegaly, fever, and crackles Findings may become more obvious after a child receives fluid boluses, emphasizing the importance of serial examinations between fluid boluses EKGs are abnormal in over 90% of patients; the most common EKG findings are sinus tachycardia, low-voltage QRS complexes, and T-wave inversion Chest radiographs are abnormal in 60% to 90% of children, most commonly showing cardiomegaly and pulmonary edema Laboratory evaluation should include troponin, creatine kinase MB, B-type natriuretic peptide (BNP), and early cardiology intervention should be sought Standard precautions should be used Pericarditis is caused by a more heterogeneous group of pathogens (enterovirus being the primary viral etiology, while pneumococcus, meningococcus, S aureus, and tuberculosis are among the more common bacterial causes) Rheumatologic disorders, uremia, pancreatitis, and other noninfectious etiologies can also result in pericardial inflammation Symptoms are nonspecific and include fever, cough, shortness of breath, abdominal pain, and vomiting Chest pain is an early finding, is worst over the precordium, may radiate to the left shoulder, is worse when supine, and alleviated when the child is sitting upright or leaning forward Examination findings include a pericardial friction rub, muffled heart tones, tachycardia, jugular venous distension (JVD), and narrowed pulse pressures Pulsus paradoxus, where the systolic blood pressure decreases by >10 mm Hg with inspiration, is concerning for tamponade physiology Beck triad is pathognomonic for tamponade: JVD, muffled heart sounds, and hypotension EKGs are abnormal in >90% Diffuse ST elevation is seen first, followed by ST depression and PR decrease, then normalization of intervals with T-wave inversions As the pericardial effusion increases, QRS voltages are dampened and there may be evidence of electrical alternans The chest radiograph often is normal in pericarditis, as it is estimated that an effusion has to be at least 250 mL (in adults) before being apparent on plain radiograph Early cardiology intervention and echocardiogram are critical Nonsteroidal anti-inflammatory drugs are the mainstay of pericarditis treatment Children with tamponade physiology may require pericardiocentesis Standard precautions should be used GASTROINTESTINAL INFECTIOUS EMERGENCIES Gastroenteritis is an inflammation of the alimentary tract that, in its acute form, is overwhelmingly infectious in origin Viruses are the organisms most commonly found in children with diarrhea in the United States and can be isolated from approximately 30% of patients In 10% of patients, bacteria are recovered, including Salmonella, Shigella, Campylobacter, Yersinia, and pathogenic E coli Clostridium difficile, which elaborates a toxin, may