Mitral stenosis

What it is

Mitral stenosis is the chronic valve disease left behind by rheumatic heart disease. In rheumatic valvular heart disease the acute valve problem is MR and the chronic one is MS, mitral stenosis. Chronic rheumatic heart disease is the complication of rheumatic fever, and most commonly it is mitral stenosis.

Causes and risk

The most common cause is rheumatic heart disease. Mitral stenosis is NOT a complication of mitral valve prolapse. Rheumatic fever is a post-infectious immune response to Group A Streptococcus, Streptococcus pyogenes, in which molecular mimicry leads to an autoimmune attack on heart, joints, skin and CNS. It is diagnosed by evidence of recent GAS infection, by throat culture or ASO, plus either 1) 2 major criteria, or 2) 1 major and 2 minor criteria. The five major criteria are:

1. Joints: migratory polyarthritis
2. Carditis: pancarditis with endocarditis, myocarditis and pericarditis
3. Subcutaneous nodules: painless and firm
4. Erythema marginatum: a painless, ring-shaped rash
5. Sydenham's chorea: involuntary movements with emotional lability

The minor criteria are:

1. Fever
2. Arthralgia
3. A rise in ESR and CRP
4. A prolonged PR interval

In the adult mitral stenosis is virtually always rheumatic. And the absence of a remembered attack does not undo that, because only 50% of patients remember an episode that could have been rheumatic fever. So a woman found to have mitral stenosis on echocardiography who does not remember rheumatic fever is, in the adult, still a rheumatic valve.