Myocarditis
Causes of Myocarditis
Viral agents and disorders
Bacterial agents and disorders
Spirochetal disorders
Myocotic agents and disorders
Rickettsial disease
Protozoal disease
Helminthic agents and diseases
Cardiotoxins
Causes of hpersensitivity reactions
Systemic disorders
Celiac disease, Connective tissue disorders, Hypereosinophilia, Kawasaki disease, Sarcoidodis, Thyrotoxidosis, Wgener granumlomatosis
Symptoms and Signs:
Most patients are asymptomatic; some have Sx mimics myocardial infarction, with acute onset of chest pain, tachyarrhythmia, or sudden death, some with heart failure Sx.
Lab Abnormalities:
Abnormal ECG with nonspecific ST-T changes, ST elevation mimicking acute MI, various degrees of blockade of the AV node. The presence of Q waves or buble brach block is associated with increased rates of heart transplant or death.
Elevated serum Troponin I, troponin T, and CK-MB
Echocardiography may show left ventricular dysfunction with global hypokinesis with or without pericardial effusion.
To diagnose myocarditis with 80% sensitivity, an estimated 17 endomyocardial biopsies are necessary.
Cardiac MRI may be useful for diagnosing myocarditis associated with edema, hypremia, and fibrosis sensitive sequences.
Focal myocardial gasolinium enhancement, couple with regional wall motion abnormalities on echocardiography, yielded a positive predictive value of 71% and a negative predictive value of 100%.
Treatment of Myocarditis
In viral myocarditis, because patients generally present days to weeks after the initial viral infection, antiviral therapy has limited applicability in patients with acture viral mnyocarditis.
Azathoprine and prednisone improved cardiac function in some patients.
REF: Mayo Clin Proc Nov 2009;84(11):1001
2010