Makindo Medical Notes

Related Subjects: |Congenital Acyanotic Heart Disease |Congenital Cyanotic Heart Disease |Cardiac Embryology |Cyanosis - Central and Peripheral |Down's syndrome (Trisomy 21) |Tetralogy of Fallot |Patent Foramen Ovale (PFO) |Ventricular Septal defect (VSD) |Mitral Regurgitation (Incompetence) |Mitral Stenosis |Mitral Stenosis vs Regurgitation |Mitral Valve prolapse |Atrial Fibrillation (AF) |Cardiac Valve replacement |Prosthetic Valves<

MacCallum’s Plaque 🧾: Typically at base of posterior mitral leaflet. Caused by subendocardial Aschoff bodies (necrotic core + lymphocytes). These lesions heal with extensive myocardial fibrosis.

📖 Introduction

• Autoimmune condition triggered by Streptococcus pyogenes 🦠.
• Molecular mimicry → antibodies cross-react with cardiac myosin & sarcolemmal proteins.
• Pancarditis: endocarditis, myocarditis & pericarditis.

🌍 Epidemiology

• Common cause of acquired heart disease in low-income countries.
• Declining incidence in Europe/North America over past 4–6 decades.
• High burden in Pacific, South Asia, Sub-Saharan Africa.
• Low-risk = incidence < 2 per 100,000 children (5–14y).

🧬 Aetiology

• Triggered by GAS pharyngitis (not skin infection).
• Immune cross-reactivity → Aschoff nodules (granulomatous inflammation).
• Valve damage → stenosis + regurgitation (mitral > aortic > tricuspid > pulmonary).

🩺 Clinical Features

• Fever, lethargy, anorexia.
• ❤️ Pancarditis → new murmurs (Carey Coombs mid-diastolic), pericarditis, cardiomegaly.
• 🦵 Migratory polyarthritis → knees, ankles, elbows, wrists.
• 🌸 Erythema marginatum → pink rings on trunk/limbs.
• 📍 Subcutaneous nodules → painless, extensor surfaces.
• 🧠 Sydenham chorea → emotional lability + jerky movements (late).

🧪 Investigations

• FBC/ESR/CRP → raised.
• ECG → prolonged PR, arrhythmias.
• CXR → cardiomegaly, pulmonary edema.
• Echo → valve damage, dilatation.
• ASO titre ↑ (evidence of strep).

⚖️ Jones Criteria (Revised)

Diagnosis = 2 major OR 1 major + 2 minor, + evidence of recent GAS infection.

💊 Management

• Bed rest + supportive care.
• Aspirin / NSAIDs for arthritis.
• Steroids (severe carditis).
• Anticonvulsants (valproate, carbamazepine) for chorea.

🚑 Eradication & Prophylaxis

• Acute episode: Penicillin V (10 days) or IM benzathine penicillin. Alternatives = erythromycin.
• Secondary prophylaxis (to prevent recurrence):
  • No carditis → 5y or until age 21.
  • Carditis, no residual disease → 10y or until 21.
  • Severe carditis with valve disease → ≥10y, sometimes lifelong.