Rheumatic Fever
Summary
Acute Rheumatic Fever (ARF) is a non-suppurative, autoimmune complication of Group A Streptococcus (GAS) pharyngitis. It is a multisystem disease characterized by inflammation of the joints, heart, skin, and nervous system. It primarily affects children aged 5-15. While rare in developed nations, it remains a major cause of acquired heart disease (Rheumatic Heart Disease - RHD) in developing countries and indigenous populations (e.g., Aboriginal Australians, Maori). [1,2]
The Adage
"Rheumatic Fever licks the joints but bites the heart." The arthritis is painful but resolves completely without damage. The carditis can leave permanent valvular scarring (RHD).
Clinical Pearls
Sydenham's Chorea ("St Vitus' Dance"): A late manifestation (can occur 3-6 months after infection). The patient presents with involuntary, jerky movements ("milkmaid's grip", "darting tongue") and emotional lability. It is diagnostic of ARF even without other Jones criteria.
Carey Coombs Murmur: A soft, mid-diastolic murmur heard at the apex during acute valvulitis. It is due to "relative mitral stenosis" (the valve is swollen and edematous, restricting flow).
Aspirin in Children: ARF is one of the only indications for high-dose Aspirin in paediatrics (despite the risk of Reye's Syndrome), because its anti-inflammatory effect on the joints is spectacular ("The Salicylate Miracle" - pain vanishes in 24h).
Demographics
- Age: Peak 5-14 years. Rare less than 3 years.
- Geography: Endemic in sub-Saharan Africa, Pacific Islands, and Aboriginal Australia.
- Aetiology: Follows untreated Group A Beta-Haemolytic Strep (Strep pyogenes) pharyngitis by 2-4 weeks. (Note: It does NOT follow Strep skin infections/impetigo - that causes Glomerulonephritis).
Molecular Mimicry
- Infection: GAS pharyngitis occurs.
- Immune Response: Body creates antibodies against the Strep M-Protein.
- Cross-Reactivity: The M-Protein shares structural homology with human tissues (Cardiac Myosin, Synovium, Basal Ganglia).
- Autoimmunity: Antibodies attack the heart valves (Carditis), joints (Arthritis), and brain (Chorea).
- Aschoff Bodies: Pathognomonic granulomas found in the myocardium.
The Jones Criteria (2015 Revision)
Diagnosis generally requires Evidence of Antecedent Strep Infection PLUS:
(Note: Criteria are relaxed for High-Risk populations).
Major Criteria (JONES)
- J - Joints (Polyarthritis): Migratory. Large joints (Knees, Ankles, Elbows). Hot, red, swollen, excruciatingly painful. (Does not cause permanent damage).
- O - Carditis: Pancarditis (Pericarditis, Myocarditis, Valvulitis). New murmur (MR/AR).
- N - Nodules: Subcutaneous, painless, firm lumps over bony prominences (elbows/spine). Rare (less than 5%).
- E - Erythema Marginatum: Pink, serpiginous ("snake-like"), non-pruritic rash on trunk. Spares face.
- S - Sydenham's Chorea: Involuntary movements.
Minor Criteria
- Heart: Pan-systolic murmur (Mitral Regurgitation). Tachycardia.
- Joints: Assess for redness/swelling.
- Neuro: "Milkmaid's Grip" (waxing/waning grip strength). "Pronator Drift" (hands pronate when arms extended overhead - "Chorea signs").
Evidence of Strep
- ASOT (Anti-Streptolysin O Titer): Rising or elevated (>200) is the Gold Standard retrospective confirmation.
- Anti-DNase B: Another antibody titer.
- Throat Swab: Often negative by the time ARF develops (2 weeks later).
Cardiac
- ECG: First degree heart block (Prolonged PR).
- Echocardiogram: Mandatory. Can detect "Subclinical Carditis" (valvulitis seen on echo but not heard).
Management Algorithm
DIAGNOSIS OF ARF
(Jones Criteria)
↓
STEP 1: ERADICATE STREP
- Benzathine Penicillin IM (Stat)
OR Penicillin V Oral (10 days)
(Even if throat swab negative)
↓
STEP 2: ANTI-INFLAMMATORY
┌─────────┴─────────┐
ARTHRITIS ONLY CARDITIS
↓ ↓
ASPIRIN STEROIDS
(High dose) (Prednisolone)
(75-100mg/kg) (2mg/kg)
↓ ↓
STEP 3: SECONDARY PROPHYLAXIS
(To prevent RHD recurrence)
- IM Benzathine Penicillin G
every 4 weeks (Standard)
Prophylaxis Duration (The Australian Guideline)
- No Carditis: For 5 years (or until age 21).
- Mild Carditis (Healed): For 10 years (or until age 21).
- Severe Valve Disease: Until age 35-40, or possibly lifelong.
- Rheumatic Heart Disease (RHD):
- Mitral Stenosis: Occurs 10-20 years later. "Fish mouth" valve.
- Mitral Regurgitation: The acute lesion.
- Jaccoud's Arthropathy: Rare, reversible deformity of hands from repeated attacks.
- Recurrence: VERY high risk if re-exposed to Strep. Recurrences worsen heart damage.
- Mortality: Low in acute phase (less than 1%), but significant long-term morbidity from heart failure.
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Jones Criteria (2015) | AHA | Added "Subclinical Carditis" as a Major criterion. Differentiated Low vs High risk populations. |
| RHD Guidelines | RHD Australia | World-leading protocol on secondary prophylaxis. |
Landmark Evidence
1. The Introduction of Penicillin
- Historical data conclusively showed that penicillin treatment of acute pharyngitis reduced ARF incidence by >70% in military recruits.
What caused this?
It started with a sore throat (Strep throat) a few weeks ago. Your child's immune system made antibodies to kill the bacteria. Unfortunately, the bacteria looks very similar to the heart and joint tissues, so the antibodies got confused and started attacking the body itself.
Will the joints recover?
Yes. The arthritis is very painful now, but once we start the Aspirin, it will vanish like magic, and it leaves no permanent damage.
Will the heart recover?
The heart valves are inflamed. In mild cases, they heal. In severe cases, they can be scarred (Rheumatic Heart Disease). This is why we must prevent any future Strep infections.
Why the monthly injections?
If your child gets Strep throat again, the immune system will attack the heart even harder. The monthly penicillin injection guarantees no Strep can survive in the throat, protecting the heart from further damage.
Primary Sources
- Gewitz MH, et al. Revision of the Jones Criteria for the diagnosis of acute rheumatic fever in the era of Doppler echocardiography: a scientific statement from the American Heart Association. Circulation. 2015.
- RHD Australia (ARF/RHD Guideline Writing Group). The 2020 Australian guideline for prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease. 2020.
Common Exam Questions
- Diagnosis: "Migratory arthritis + New murmur?"
- Answer: Rheumatic Fever.
- Pathology: "Aschoff bodies?"
- Answer: Rheumatic Carditis.
- Treatment: "Drug for the joint pain?"
- Answer: Aspirin.
- Neuro: "St Vitus Dance?"
- Answer: Sydenham's Chorea.
Viva Points
- Subclinical Carditis: The 2015 guidelines allow you to diagnose "Carditis" based on Echo findings alone (e.g., mitral regurgitation) even if you can't hear a murmur.
- Erythema Marginatum: Can be provoked by heat (bath).
- PR Interval: First degree block is common but benign.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.