A 58-year-old man from rural India presents with progressive dyspnea, orthopnea, and a loud diastolic murmur at the apex. Echocardiography confirms severe mitral stenosis. What is the most common cause of mitral stenosis in India?

Explanation

## Most Common Cause of Mitral Stenosis in India **Key Point:** Rheumatic heart disease (RHD) accounts for >90% of mitral stenosis cases in developing countries, including India. It remains the leading cause of acquired valvular disease in the Indian subcontinent. **High-Yield:** The prevalence of RHD is significantly higher in India due to: - High incidence of acute rheumatic fever (ARF) in childhood - Recurrent streptococcal infections - Limited access to antibiotics and early treatment - Poor socioeconomic conditions and overcrowding ### Pathophysiology of RHD-Related Mitral Stenosis 1. **Initial insult:** Group A Streptococcal pharyngitis → acute rheumatic fever 2. **Valve damage:** Pancarditis with endocarditis → fibrosis and commissural fusion 3. **Chronic sequelae:** Progressive stenosis over 10–20 years post-ARF 4. **Hemodynamic consequence:** Increased left atrial pressure → pulmonary congestion ### Comparison of Mitral Stenosis Etiologies | Cause | Frequency (India) | Frequency (West) | Key Features | | --- | --- | --- | --- | | **Rheumatic heart disease** | >90% | 65–70% | History of ARF, commissural fusion, atrial fibrillation common | | **Mitral valve prolapse** | <1% | 2–3% | Rarely causes stenosis; usually regurgitation | | **Congenital mitral stenosis** | <1% | 1–2% | Presents in infancy/childhood; parachute mitral valve | | **Infective endocarditis** | <1% | <1% | Acute presentation; vegetation + septic emboli | **Clinical Pearl:** In an Indian patient with mitral stenosis, always ask about: - History of recurrent sore throats in childhood - Rheumatic fever diagnosis or symptoms - Penicillin prophylaxis compliance - Family history of RHD **Mnemonic — RHD Sequelae (CHAMP):** - **C**ommissural fusion (mitral stenosis) - **H**ypertrophic changes (left atrium) - **A**trial fibrillation (common complication) - **M**itral regurgitation (may coexist) - **P**ancarditis (initial inflammation) **Warning:** Do not confuse mitral valve prolapse (MVP) with mitral stenosis. MVP typically causes a late systolic murmur and regurgitation, not stenosis. Calcification of MVP is rare and does not cause hemodynamically significant stenosis. [cite:Harrison 21e Ch 298]