History
The clinical presentation of nonviral myocarditis varies considerably; factors that influence the clinical presentation include etiologic agent, age, sex, and immunocompetence. [1, 2, 3, 4] Many patients with myocarditis are asymptomatic, whereas others may present with a fulminant, rapidly progressive, fatal illness.
Clinical manifestations of myocarditis, regardless of etiology, tend to be more severe in newborns than in older infants and children. Symptoms in newborns are nonspecific and include the following:
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Lethargy
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Poor feeding
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Cyanosis
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Respiratory distress
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Tachypnea
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Tachycardia
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Vomiting
In older infants and children, the symptoms often encountered include the following:
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Low-grade fever
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Irritability
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Mild respiratory symptoms
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Abdominal pain
Physical Examination
The physical examination may include verification of the symptoms listed under History. The nonspecific signs and symptoms noted in infants with myocarditis may be evidenced on physical examination but may also be documented in the patient's history. Fever, irritability, respiratory signs, and abdominal pain may be noted on physical examination of children and adults with myocarditis. If the disease has progressed, physical examination usually reveals the following:
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Decreased cardiac output
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Pallor and cool skin in distal extremities
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Rapid respirations
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Possible thready pulse
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Tachycardia usually present (gallop rhythm may be heard)
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Progressive heart failure
A mitral regurgitant murmur—a blowing, holosystolic murmur heard best at the apex of the heart—may be present. The lung examination may show scattered rhonchi and rales. Full cardiovascular collapse is possible.
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Pediatric nonviral myocarditis. This image is reveals myocarditis with scarring at autopsy. It is a short-axis gross photograph from an 8-year-old child who had clinical myocarditis, showing scarring of both ventricles, more prominent in the left. The fibrosis depicts a random distribution with epicardial, myocardial, and pericardial involvement.
