Definition:
Rheumatic Fever is an acute, immune-mediated disease that occurs after an episode of beta-hemolytic streptococcal pharyngitis and often involves the heart.
Major Clinical Manifestations/ Criteria for Diagnosis.
1. Migratory polyarthritis of large joints.
2. Carditis
3. Subcutaneous nodules
4. Erythema marginatum
5. Sydenhom chorea ( it is a neurological disorder with involuntary purposeless movements.)
Minor Clinical manifestations/ Diagnostic criteria
1. Fever
2. Arthralgias.
3. Elevated acute phase reactants.
Jones Criteria for diagnosis of Rheumatic Fever.
A physician should diagnose Rheumatic fever if there is
1. History of beta-hemolytic streptococcal infection.
2. Presence of Two major manifestations or one major and two minor manifestations.
Morphology:
1. Aschoff bodies (foci of fibrinoid necrosis)
2. Anitschkow cells (these are plasma cells surrounded by macrophages)
3. Pancarditis
4. Bread and butter pericarditis (because of serofibrinous pericardial exudate)
5. Verrucae or valvular vegetations (fibrinoid necrosis within the cusps of valves)
6. Maccallum plaques.
7. Thickening of leaflets of valves.
8. Fibrous bridging across commissural fusions called fish mouth button hole stenosis.
9. Subendocardial thickening usually in the left atrium.
Pathogenesis:
Antibodies directed against M protein of certain strains of streptococci cross-react with tissue strains of streptococci cross-react with tissue glycoprotein of heart, joints and other tissues, thus initiating the inflammation and tissue damage.