Rheumatic fever and Rheumatic Heart Disease
Clinical:Children ages 5-15; onset 10 days to 6 weeks after episode of pharyngitis
Pathophysiology: Follows 3% group A (b-hemolytic) streptococcal pharyngitis. Antibodies directed against M protein cross-react with tissue glycoproteins.
Diagnosis: Serological evidence: anti-streptolysin O or anti-DNAse B
Jone’s criteria: evidence of a preceeding Group A strep infection with 2 major or 1 major and 2 minor sx:
Major – migratory polyarthritis, carditis, subcutaneous nodules, erythema marginatum, Sydenham chorea
Minor – fever, arthralgia, PR interval on EKG, ESR, C reactive protein
Treatment: Antibiotics in acute disease;
Prognosis: 1% die of fulminant rheumatic fever; reactivation of disease occurs with subsequent pharyngeal infections causing cumulative damage; long term prognosis is highly variable.
Acute: Bread and butter pericarditis, valvular vegetations (verrucae) along lines of closure, MacCallum plaques caused by regurgitation
Chronic: 99% of mitral stenosis [mitral valve alone involved in 65-70%; mitral and aortic valve in 25%]; mitral and aortic valve leaflet thickening; commissural fusion; shortening, thickening and fusion of tendinous cords; fishmouth or buttonhole stenosis
Acute: Pancarditis with Aschoff bodies (foci of fibrinoid degeneration surrounded by lymphocytes); plum macrophages (Anitschkow cells, caterpillar cells), multinucleated Aschoof giant cells
Chronic: valvular fibrosis and neovascularization