Question
Two non-suppurative sequelae of streptococcus pyogenes infection.
Answer
Two non-suppurative complications of Streptococcus pyogenes (Group A Streptococcus) infection — immune-mediated delayed sequelae, occurring after the primary infection has often already resolved:
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Acute rheumatic fever — follows streptococcal pharyngitis, 2–4 weeks later; caused by molecular mimicry, where antibodies against streptococcal M protein cross-react with cardiac myosin/valve tissue, causing carditis, migratory polyarthritis, Sydenham’s chorea, and other Jones-criteria features.
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Acute post-streptococcal glomerulonephritis (PSGN) — can follow pharyngitis or skin infection (impetigo), typically 1–3 weeks (pharyngitis) or 3–6 weeks (skin infection) later; caused by deposition of circulating immune complexes in the glomerular basement membrane, presenting with haematuria, oedema, and hypertension.
Both are driven by the host’s immune response to the organism rather than by ongoing bacterial presence at the affected organ.