Rheumatic Fever
Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management
Definition
Rheumatic fever is an inflammatory autoimmune condition that develops as a complication of untreated or inadequately treated Group A Streptococcus (GAS) pharyngitis, leading to multisystem involvement, including the heart, joints, skin, and central nervous system.
Aetiology
- Caused by an immune-mediated response to Group A Streptococcus (Streptococcus pyogenes).
- Follows untreated or inadequately treated streptococcal pharyngitis.
- Molecular mimicry leads to cross-reactivity between streptococcal antigens and host tissues.
Pathophysiology
- Streptococcal infection triggers an autoimmune response.
- Antibodies cross-react with cardiac, synovial, skin, and neuronal tissue.
- Inflammation leads to rheumatic heart disease (valvular damage), arthritis, and chorea.
Risk Factors
- Untreated or recurrent streptococcal throat infections.
- Overcrowded living conditions and poor hygiene.
- Children aged 5-15 years.
- Family history of rheumatic fever.
- Low-income settings with limited healthcare access.
Signs and Symptoms
- Develops 2-4 weeks after streptococcal pharyngitis.
- Major criteria (Jones criteria):
- Carditis (pancarditis, new murmur, heart failure).
- Migratory polyarthritis (large joints, asymmetric involvement).
- Syndenham chorea (involuntary movements, emotional lability).
- Erythema marginatum (non-pruritic, annular rash on the trunk).
- Subcutaneous nodules (firm, painless, over bony prominences).
- Minor criteria:
- Fever.
- Arthralgia.
- Elevated inflammatory markers (ESR, CRP).
- Prolonged PR interval on ECG.
Investigations
- Throat swab: culture for Group A Streptococcus.
- Antistreptolysin O (ASO) titre: elevated in recent streptococcal infection.
- Inflammatory markers: raised ESR and CRP.
- ECG: may show prolonged PR interval.
- Echocardiography: assess valvular involvement.
Management
1. Eradication of Streptococcus:
- Penicillin V (10-day course).
- Macrolides if penicillin allergy.
2. Anti inflammatory Treatment:
- Aspirin or NSAIDs for arthritis.
- Corticosteroids for severe carditis.
3. Symptomatic Management:
- Supportive care for Syndenham chorea.
- Heart failure management if carditis is severe.
4. Secondary Prevention:
- Long term penicillin prophylaxis (IM benzathine penicillin every 3-4 weeks) to prevent recurrence.
- Duration of prophylaxis depends on severity and presence of carditis.
5. Referral:
- Cardiology: for rheumatic heart disease assessment.
- Neurology: for severe Syndenham chorea.
- Paediatrics: for children requiring long-term follow-up.