Acute Rheumatic Fever
📌 Epidemiology (High Yield):
• Age: 5–15 years (Children/Young Adults).
• Incidence: Rare in West (0.5/100k); Endemic in South Asia, Africa.
• India: Commonest cause of acquired heart disease in childhood (13–150 cases per 100k).
• Age: 5–15 years (Children/Young Adults).
• Incidence: Rare in West (0.5/100k); Endemic in South Asia, Africa.
• India: Commonest cause of acquired heart disease in childhood (13–150 cases per 100k).
1. Pathogenesis
Triggered by an immune-mediated delayed response to infection with specific strains of Group A Streptococci.
- Mechanism: Molecular Mimicry. Antigens cross-react with cardiac myosin and membrane proteins.
- Histology: Fibrinoid degeneration of collagen.
- Pathognomonic Sign: Aschoff Nodules (Multinucleated giant cells). Seen in subacute/chronic phases.
Figure: Pathogenesis & Aschoff Nodules
2. Clinical Features
Presents 2–3 weeks after Streptococcal pharyngitis.
A. Carditis (Pancarditis) ❤️
Involves Endocardium, Myocardium, and Pericardium. Incidence declines with age.
- Mitral Regurgitation (MR): Soft systolic murmur (Most common).
- Carey Coombs Murmur: Soft mid-diastolic murmur due to valvulitis.
- Aortic Regurgitation: Occurs in 50% of cases.
- Pericarditis: Friction rub, chest pain.
B. Arthritis 🦵
- Occurs in 75% of patients (Early feature).
- Pattern: Acute, painful, asymmetric, migratory inflammation of large joints (knees, ankles, elbows).
- Highly responsive to Aspirin (Diagnostic).
C. Skin & CNS
- Sydenham’s Chorea: Late feature (>3 months). "St Vitus Dance" – purposeless movements, emotional lability.
- Erythema Marginatum: Red rings on trunk, spares the face (<5% cases).
- Subcutaneous Nodules: Painless, firm nodules over extensor surfaces.
3. Revised Jones Criteria
Diagnosis = 2 Major OR 1 Major + 2 Minor
(+ Evidence of preceding Strep Infection*)
(+ Evidence of preceding Strep Infection*)
★ Major Criteria
- Carditis
- Polyarthritis
- Chorea
- Erythema Marginatum
- Subcutaneous Nodules
✓ Minor Criteria
- Fever
- Arthralgia
- Raised ESR/CRP
- Prolonged PR Interval
- Previous RF
4. Investigations
- Inflammatory Markers: ESR & CRP (Monitor progress).
- Throat Culture: +ve in only 10-25% of cases.
- Serology: ASO Titers (Antistreptolysin O) - supportive evidence.
- Echo: Shows MR, dilated annulus, pericardial effusion.
5. Management
Aims: Limit cardiac damage and relieve symptoms.
Step 1: Bed Rest 🛏️
Lessens joint pain and reduces cardiac workload. Continue until ESR/Temp settles.
Step 2: Antibiotic Therapy 💊
Goal: Eliminate residual Strep infection.
Primary Choice (Select one):
- Inj. Benzathine Benzylpenicillin: 1.2 Million Units IM (Stat)
- Tab. Phenoxymethylpenicillin: 250 mg QID × 10 Days
⚠️ Penicillin Allergy: Use Erythromycin or Cephalosporin.
Step 3: Anti-Inflammatory Drugs
| Condition | Drug of Choice | Dosage & Duration |
|---|---|---|
| Arthritis | Aspirin |
• Child: 60 mg/kg/day • Adult: 100 mg/kg/day (Max 8g) Continue until ESR falls, then taper. |
| Carditis / Severe Arthritis | Prednisolone (Steroids) |
• Dose: 1.0 – 2.0 mg/kg/day Taper gradually once ESR normalizes. |
Step 4: Secondary Prophylaxis 🛡️
Essential to prevent recurrence.
Regimen:
• Choice A: Inj. Benzathine Penicillin 1.2 Million Units IM Monthly (Best for adherence).
• Choice B: Oral Penicillin V 250 mg BD.
Duration:
• No Carditis: Until age 21 (or 5 years post-attack).
• With Carditis (Residual Heart Disease): Until age 40 (or 10 years post-attack).
• Choice A: Inj. Benzathine Penicillin 1.2 Million Units IM Monthly (Best for adherence).
• Choice B: Oral Penicillin V 250 mg BD.
Duration:
• No Carditis: Until age 21 (or 5 years post-attack).
• With Carditis (Residual Heart Disease): Until age 40 (or 10 years post-attack).
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