Pathology of Rheumatic Fever and Rheumatic Heart disease ; Definition, causes, Pathogenesis, Morphol

Описание: Rheumatic Fever (RF) and Rheumatic Heart Disease (RHD) are interconnected conditions caused by an autoimmune response to Group A beta-hemolytic streptococcal infection, typically following untreated strep throat.

Pathology of Rheumatic Fever:
Immune Response: RF is an inflammatory disease where the immune system mistakenly attacks the body's tissues due to molecular mimicry between streptococcal antigens and human tissues.

Affected Areas: It primarily affects the heart, joints, skin, and central nervous system.

Cardiac Involvement: Inflammation can involve all layers of the heart (pancarditis), leading to myocarditis, pericarditis, and endocarditis. Aschoff bodies (granulomatous lesions) and Anitschkow cells (caterpillar-like histiocytes) are hallmark findings in the myocardium.

Other Manifestations: Migratory arthritis, Sydenham's chorea, erythema marginatum, and subcutaneous nodules are common clinical features.

Pathology of Rheumatic Heart Disease:
Chronic Sequelae: RHD is the long-term consequence of repeated or severe RF episodes, leading to permanent damage to the heart valves.

Valve Damage: The mitral valve is most commonly affected, followed by the aortic valve. Chronic inflammation causes fibrosis, thickening, and calcification, resulting in stenosis or regurgitation.

Gross Features: The valves may exhibit a "fish-mouth" appearance due to scarring and deformation.

Microscopic Features: Persistent inflammation and fibrosis are evident, with Aschoff bodies and thickened chordae tendineae

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