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  1. Endomyocardial biopsy
    • Definite myocarditis is findings of both myocyte degeneration of necrosis and definite cellular infiltrate (usually lymphocytes) with or without fibrosis.
    • Borderline myocarditis is definite cellular infiltrate without myocyte injury.
  2. Clinical
    • Flu-like illness in the preceding month
    • Symptoms of fatigue, malaise, shortness of breath, and chest pain
    • Evidence of congestive heart failure on PE and/or chest x-ray
    • AV block or arrhythmia on EKG
    • Decreased ventricular function by echocardiography

Unknown, due to wide range in severity from asymptomatic to sudden cardiovascular failure. Prevalence in an urban tertiary care children's hospital emergency department was 1 per 20,000 visits2. Bimodal age distribution includes 0-3 years (30%) and 13-18 years (40%).2


  1. Infectious
    • Viral - enterovirus (coxsackievirus) and adenovirus
    • Bacterial - Corynebacterium diphtheriae, Lyme disease (Borrelia burgdorferi)
    • Fungal
    • Protozoal - Chagas disease (Trypanosoma cruzi)
    • Parasitic
  2. Medications
    • Toxicity (doxorubicin)
    • Hypersensitivity (cyclophosphamide)
  3. Autoimmune diseases (JRA, SLE, IBD)
  4. Poisons (ethanol, heavy metals, envenomation, and radiation)
  5. Other inflammatory diseases (Kawasaki disease, sarcoidosis, Takayasu's disease)

Symptoms and Signs (nonspecific, often age dependent, varies with severity)2

  1. respiratory (cough, short of breath, tachypnea, wheezing, rales, cyanosis) - 32%
  2. cardiac (chest pain, palpitations, gallop rhythm, hepatomegaly) - 29%
  3. hypoperfusion (lethargy, dizziness, syncope, seizures, pale, diaphoretic, delayed cap refill, tachycardic, hypotension) - 23%
  4. Kawasaki associated - 10%
  5. gastrointestinal (nausea, vomiting, abdominal pain) - 7%

Laboratory and radiographic tests2

  1. CXR (normal in 45%)
    • cardiomegaly, pulmonary vascular congestion, pleural effusion
  2. EKG (normal in 7%)
    • ST or T wave abnormalities, axis deviation, ventricular hypertrophy, heart block, infarction pattern, decreased ventricular voltage, arterial enlargement)
    Note: 97% of children with myocarditis have an abnormal CXR or EKG
  3. Echocardiogram (normal in 13%)
    • decreased function (ejection and/or shortening fraction), valvular regurgitation, left ventricular dilation, pericardial effusion, wall motion abnormality
  4. Serum aspartate aminotransferase (AST)
    • elevated in 87%
  5. Troponins4
    • elevated in 71%

Note: "The diagnosis of myocarditis is dependent in large part on clinical suspicion rather than definite diagnostic tests."5


  1. Respiratory support
    • oxygen
    • positive pressure ventilation decreases afterload, decreases pulmonary edema, improves gas exchange and thus decreases oxygen consumption and improves cardiac output (RSI - etomidate and rocuronium)
  2. diuresis
    • lasix, 1mg/kg/dose IV
  3. inotropic support
    • dobutamine, 5-20 mcg/kg/min IV
    • dopamine, 5-10 mcg/kg/min IV
    • epinephrine, 0.03-0.1 mcg/kg/min
  4. afterload reduction (low cardiac output and high systemic vascular resistance)
    • milrinone, 0.25-1mcg/kg/min IV
  5. antiarrhythmic (ventricular)
    • amiodarone, 5mg/kg IV over 30 min, then 5-10mcg/kg/min
  6. Pediatric Cardiology consult
  7. Other
    • rapid glucose test


  1. Mazor R, Salerno JC. Evaluation and Management of Pediatric Acute Infectious Myocarditis. Pediatric Emergency Medicine Practice. 2008;5:1-16.
  2. Freedman SB, Haladyn JK, Floh A, et al. Pediatric Myocarditis: Emergency Department Clinical Findings and Diagnostic Evaluation. Pediatrics. 2007;120:1278-1285.
  3. Bass A, Fairbrother D, Perkin RM. Presentation, Assessment, and Management of Acute Myocarditis in Infants and Children. Pediatric Emergency Medicine Reports. 2008;13:29-38.
  4. Lippi G, Salvagno GL, Guidi GC. Cardiac Troponins in Pediatric Myocarditis. Pediatrics. 2008;121;864-865.
  5. Feldman AM, McNamara D. Myocarditis. NEJM. 2000;343:1388-1398

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