Which of the following is the most common cause of pure mitral stenosis in India?

Explanation

## Aetiology of Mitral Stenosis **Key Point:** Rheumatic heart disease (RHD) is the most common cause of mitral stenosis worldwide and particularly in India, accounting for >90% of cases in developing nations. ### Pathophysiology Rheumatic fever leads to: 1. Acute inflammation of valve leaflets 2. Fibrosis and calcification over years 3. Commissural fusion and leaflet thickening 4. Progressive narrowing of mitral orifice ### Other Causes of Mitral Stenosis (Less Common) | Cause | Frequency | Notes | |-------|-----------|-------| | Rheumatic heart disease | >90% (India) | Post-streptococcal, recurrent ARF | | Mitral annular calcification | Rare | Elderly, chronic kidney disease, hyperparathyroidism | | Congenital parachute MV | Very rare | Single papillary muscle, pediatric | | SLE | Rare | Libman-Sacks endocarditis | | Carcinoid syndrome | Rare | Right-sided valves primarily | | Prosthetic valve thrombosis | Iatrogenic | Post-MVR | **High-Yield:** In any Indian patient with mitral stenosis, assume RHD until proven otherwise. History of recurrent sore throat, joint pain, or rheumatic fever in childhood is highly suggestive. **Clinical Pearl:** Mitral annular calcification typically causes mitral regurgitation or a restrictive pattern, not pure stenosis. Pure mitral stenosis is almost always rheumatic in origin in India.