Pharyngeal infection with Lancefield Group A β-haemolytic streptococci of M serotype triggers rheumatic fever 2-4 weeks later, in the susceptible 2% of the pop. Due to cross-reactivity of a strep carbohydrate cell wall antigen & valve tissue. Common in the 3rd World/Aborignal/Islanders/Maori.
Peak incidence: 5-15yrs. Tends to recur (10-50%) unless prevented.
Based on the revised Jones criteria. There must be evidence of recent streptococcal infection plus 2 major criteria, or 1 major + 2 minor criteria.
Evidence of streptococcal infection: (may have been asymptomatic)
History of scarlet fever, positive throat swab, ↑ASOT >200U/mL or ↑DNase B titre
Major criteria: (ACESS)
Arthritis – A migratory, ‘flitting’ polyarthritis; usually affects the larger joints (75%).
Erythema marginatum– Geographical-type rash with red, raised edges and clear centre (never on face); occurs mainly on trunk, thighs, arms in 2–10%.
Subcutaneous nodules– Small, mobile painless nodules on jt ext surfaces & spine (2-20%).
Sydenham’s Chorea (StVitus’ dance)– Occurs late in 10%. Unilateral or bilateral involuntary semi-purposeful movements. May be preceded by emotional lability and unusual behaviour.
Minor criteria: (HEAPP)
History of previous rheumatic fever
Elevated ESR or CRP
Arthralgia (but not if arthritis is one of the major criteria).
Prolonged PR interval (but not if carditis is major criterion).
Bed rest until CRP normal for 2 weeks (may be 3 months).
Benzylpenicillin 0.6-1.2g IM stat then penicillinV 250mg/12h PO x 10 days.
Analgesia for carditis/arthritis: Aspirin 100mg/kg/day PO in divided doses (maximum 8g/day) for 2 days, then 70mg/kg/day for 6 weeks. Monitor salicylate level. Toxicity causes tinnitus, hyperventilation, metabolic acidosis. Alternative: NSAIDs
Steroids if fever/heart failure resistant.
Immobilize joints in severe arthritis.
Haloperidol (0.5mg/8h PO), valproate or diazepam for the chorea.
60% with carditis develop chronic Rh disease. Acute attacks last an ave of 3 months. Recurrence may be precipitated by further streptococcal infections, pregnancy, or use of the OCP. Cardiac sequelae affect mitral (70%), aortic (40%), tricuspid (10%), and pulmonary (2%) valves. Incompetent lesions develop during the attack, stenoses years later.
PenicillinV 250mg/12h PO until no longer at risk (30yrs). Alternative: sulphadiazine 1g daily (0.5g if <30kg). Give antibiotic prophylaxis for dental or other surgery.