What can cause myocarditis?

• A. Rheumatic heart disease, infectious processes, endocarditis, or pericarditis.
• B. Atherosclerosis and hypertension.
• C. Pulmonary embolism.
• D. Bacterial endocarditis only.

Answer: (A)

Myocarditis results from inflammation of the heart muscle caused by a mix of insults, most often infections and immune-mediated processes. Rheumatic fever can involve the myocardium as part of broader pancarditis, so rheumatic heart disease can be associated with myocarditis. Infections—viral or bacterial—can directly invade or inflame the myocardium, leading to myocarditis. When endocarditis or pericarditis are present, the inflammatory process or systemic infection can extend to the myocardium or occur together with myocarditis, producing a wider inflammatory involvement of the heart. This makes the first option the best because it covers these key etiologies that can involve the myocardium.

The other choices don’t fit as well. Atherosclerosis and hypertension primarily cause ischemic and pressure-related heart changes rather than primary myocarditis. A pulmonary embolism is a vascular event affecting the lungs and right heart, not a cause of myocarditis. Bacterial endocarditis alone is a specific infection of the valve lining and doesn’t fully account for myocarditis, which can arise from broader inflammatory or infectious processes beyond endocarditis alone.