PA26.{5,7} | Rheumatic Heart Disease & Infective Endocarditis — Summary & Reflection

REFLECT

Reflect on this progression: a treatable throat infection in a child → autoimmune carditis → 20 years of silent scarring → symptomatic mitral stenosis → atrial fibrillation → stroke or infective endocarditis.

In what ways does this sequence represent a failure of preventive medicine rather than a failure of curative medicine? Consider the role of poverty, overcrowding, health literacy, and access to antibiotics in driving the rheumatic heart disease burden in India. What systematic interventions would most effectively interrupt this cascade at a population level? How does understanding the molecular pathogenesis help you counsel a patient's family about secondary prophylaxis?

KEY TAKEAWAYS

Acute Rheumatic Fever:
• Follows GABHS pharyngitis (not skin infection) after 2–4 weeks
• Pathogenesis: molecular mimicry — antibodies against M-protein cross-react with cardiac myosin/valve glycoproteins (Type II hypersensitivity) + T-cell amplification (Type IV)
• Diagnosis: Jones criteria — 2 major OR 1 major + 2 minor + evidence of preceding GABHS infection
• Major criteria: CASES — Carditis, Arthritis (migratory), Sydenham chorea, Erythema marginatum, Subcutaneous nodules
• Pathology: Aschoff bodies (Anitschkov caterpillar cells, pathognomonic), verrucae along valve closure lines, MacCallum's plaque

Chronic RHD:
• Mitral stenosis: fish-mouth/buttonhole orifice; thickened, fused commissures; shortened chordae
• Complications: AF → stroke, pulmonary hypertension → right HF, infective endocarditis risk

Infective Endocarditis:
• Acute IE: S. aureus, normal valve, large destructive vegetations, rapid course
• Subacute IE: S. viridans, damaged valve, smaller vegetations, indolent course
• IV drug use → right-sided IE (tricuspid), septic pulmonary emboli
• Duke criteria: 2 major, OR 1 major + 3 minor, OR 5 minor = Definite IE
• Major: positive blood culture + positive echo (vegetation/abscess/new regurgitation)
• Peripheral signs: Janeway (embolic, non-tender) vs Osler (immune, tender)
• Complications: acute regurgitation, ring abscess, septic emboli (cerebral/renal/splenic/pulmonary), mycotic aneurysm, immune complex glomerulonephritis

Vegetations at a glance: Rheumatic = small, sterile, along closure line; Acute IE = large, destructive, infected; Subacute IE = medium, infected; NBTE = flat, sterile; Libman-Sacks (SLE) = both valve surfaces, sterile.