Myocarditis II: Clinical Features and Diagnostic Tests

Early myocarditis symptoms are non-specific and resemble viral infections, including fever, fatigue, malaise, myalgia, dyspnea, lymphadenopathy, nausea, and vomiting. Some patients remain asymptomatic with spontaneous infection resolution. As the condition progresses, cardiac-specific symptoms emerge, such as pleuritic chest pain and pericardial friction rub.

Physical examination for myocarditis focuses on detecting arrhythmias, crackles in the lungs suggesting pulmonary congestion, jugular venous distention indicating increased central venous pressure, syncope episodes from cardiac dysfunction, and peripheral edema signaling advanced heart failure. These findings help clinicians identify cardiac compromise and guide further diagnostic testing.

Laboratory tests in myocarditis typically show mild to moderate leukocytosis, elevated erythrocyte sedimentation rate, and increased C-reactive protein levels indicating inflammation. Elevated cardiac biomarkers, particularly troponin, indicate myocardial injury. These non-specific inflammatory markers combined with cardiac-specific enzymes support myocarditis diagnosis.

Electrocardiograms in myocarditis typically show diffuse ST-segment changes and T-wave inversions reflecting myocardial inflammation or injury. These ECG abnormalities are characteristic findings that help differentiate myocarditis from other cardiac conditions and support clinical diagnosis when combined with laboratory and imaging results.

Endomyocardial biopsy provides definitive histological diagnosis of myocarditis, particularly in acute cases. The procedure samples myocardial tissue examined for lymphocytic infiltration indicating immune response and myocyte damage showing direct myocardial injury. This invasive test confirms inflammation when clinical and laboratory findings are inconclusive.

A thorough medical history should focus on recent viral infections, travel history, and underlying autoimmune diseases predisposing to myocarditis. These details help identify potential triggers and risk factors. Combined with physical examination findings and laboratory results, comprehensive history-taking ensures accurate diagnosis and appropriate management planning.

Pericardial involvement in myocarditis manifests as pleuritic chest pain that worsens with breathing, pericardial friction rub detected as a scratchy sound during auscultation, and pericardial effusion—fluid accumulation around the heart visible on medical imaging. These clinical features indicate concurrent pericardial inflammation accompanying myocardial disease.