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For further information, see CMDT Part 10-42: Infectious Myocarditis
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Essentials of Diagnosis
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Often follows an upper respiratory infection
May present with chest pain (pleuritic or nonspecific) or signs of heart failure
Echocardiogram documents cardiomegaly and contractile dysfunction
Myocardial biopsy, though not sensitive, may reveal a characteristic inflammatory pattern; MRI has a role in diagnosis
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General Considerations
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Patients may present several days to a few weeks after the onset of an acute febrile illness or a respiratory infection or they may present with heart failure without antecedent symptoms
Onset of heart failure may be gradual or may be abrupt and fulminant
In acute fulminant myocarditis,
A pericardial friction rub may be present
In the European Study of Epidemiology and Treatment of Inflammatory Heart Disease,
Pulmonary and systemic emboli may occur
Pleural-pericardial chest pain is common
Examination reveals tachycardia, a gallop rhythm, and other evidence of heart failure or conduction defects
At times, the presentation may mimic an acute myocardial infarction with ST changes, positive cardiac markers, and regional wall motion abnormalities despite normal coronaries
Microaneurysms may also occur and may be associated with serious ventricular arrhythmias
Approximately 10% of all dilated cardiomyopathy patients have viral myocarditis as the cause
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No specific laboratory finding
However, white blood cell count is usually elevated
Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are usually increased
Troponin I or T levels are elevated in about one-third of patients, but CK-MB is elevated in only 10%
Other biomarkers, such as B-type natriuretic peptide (BNP and proBNP), are usually elevated
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Chest radiograph
Evidence for ...