Rheumatic fever

Rheumatic fever is a complication of streptococcus pyogenes (group A streptococci) infection. It typically follows a few weeks after a streptococcal pharyngitis infection, which may be subclinical and therefore go unnoticed.

The condition affects the joints, heart, CNS, and skin. The heart manifestation of rheumatic fever is called rheumatic heart disease.

Rheumatic fever is rare in developed countries nowadays as most cases of streptococcal pharyngitis are diagnosed and treated with antibiotics. However, in developing countries, diagnosis and treatment does not occur as frequently, and rheumatic fever is more common as a result. When it occurs, it mostly affects children.

Pathomechanism

In case of streptococcal infections, antibodies develop against the M protein of streptococcus pyogenes. Due to molecular mimicry, these antibodies cross-react with nerves and myocardium, causing a type II hypersensitivity reaction.

Clinical features

Rheumatic heart disease can affect the mitral or aortic valves, causing regurgitation initially and stenosis later. Rheumatic fever is the most common cause of mitral stenosis. Pancarditis is also typical.

Other features include fever, malaise, fatigue, migratory polyarthritis, Sydenham chorea, subcutaneous nodules, and erythema marginatum.

Diagnosis and evaluation

Inflammatory markers are elevated, and ECG may show 1st degree AV block. Serology for anti-streptococcal antibodies like ASO and ADB can be used to confirm recent streptococcus pyogenes infection.

The diagnosis is made based on the Jones criteria, which are based on typical clinical features.

Treatment

The treatment for rheumatic heart disease is penicillin. NSAIDs may be used for joint symptoms and pain relief.