What is the most common cause of mitral stenosis?

The most common cause of mitral stenosis is indeed untreated streptococcal infection, specifically rheumatic fever, which can occur as a complication of strep throat or other streptococcal infections. When a person contracts such an infection and does not receive appropriate treatment, the immune response can lead to rheumatic fever. This condition can cause inflammation and scarring of the heart valves, particularly the mitral valve, leading to stenosis over time.

The development of mitral stenosis as a result of rheumatic fever is significant, as it can lead to long-term complications such as heart failure or atrial fibrillation if not addressed. This historical context underscores the importance of treating streptococcal infections promptly to prevent rheumatic fever and its sequelae.

Other causes like calcification of the valve leaflets or congenital abnormalities do exist but are less common in the general population. For instance, calcification generally occurs in older patients and is associated with age-related degenerative changes rather than being the primary cause of mitral stenosis in younger populations. Similarly, congenital bicuspid valves are rarer and are not a widespread cause of mitral stenosis when considering the population as a whole. Chordae tendineae