Acute Rheumatic Fever
Group A streptococcus (GAS) aka Streptococcus pyogenes
Jones criteria for initial ARF (not subsequent)
Diagnosis:
GAS
DDx
Arthritis
Carditis
Chorea
Rx
Bed rest
Cardiac monitoring
Aspirin
IF Carditis
For Chorea in isolation, no need for above, instead, sedative options include:
1st line: phenobarbital (16-32 mg every 6-8 hr PO)
2nd line: haloperidol (0.01-0.03 mg/kg/24 hr divided bid PO)
OR chlorpromazine (0.5 mg/kg every 4-6 hr PO)
Primary prevention
Complications:
Rheumatic Heart Disease (30% of AFR)
- typically 2-4 weeks prior (on Hx in ⅔)
- ARF causing serotypes: M types 1, 3, 5, 6, 18 and 24
- Reduction in over crowding then the introduction of antibiotics reduced incidence from 200-0.5/100,000
- 2 theories
- immunologic theory: antigens to GAS recognise heart (fits as peak of antibodies coincide with clinical presentation)
Jones criteria for initial ARF (not subsequent)
Diagnosis:
- evidence of GAS AND 2 major criteria OR
- evidence of GAS AND 1 major AND 2 minor criteria
- Sydenham's Chorea
GAS
- Throat culture and antigen often negative by diagnosis
- Antibodies (ASOT, AntiDNaseB, antihyaluronidase) 80% sens if only ASOT, close to 100% with all 3
- Pancarditis (60%) (endocarditis, myocarditis, pericarditis) MV most common, then combined MV/AV
- Tachycardia, murmur, cardiomegaly, HF (hepatomegaly, Pulm/Peri Oedema)
- MR (high-pitched apical holosystolic murmur radiating to the axilla)
- if significant MR > relative MS (apical mid-diastolic murmur)
- AI (high-pitched decrescendo diastolic murmur at the upper left sternal border)
- ECHO: pericardial effusion, decreased ventricular contractility, MI/AI
- Migratory Polyarthritis (75%) with dramatic response to aspirin
- Erythema marginatum (<3%) erythematous, serpiginous, macular lesions with pale centers
- not pruritic, spares face, exacerbated by heat
- Subcutaneous nodules (<1%) firm 1cm nodules along the extensor surfaces of tendons near bony prominences
- Chorea (15%) (resolves)
- Emotional lability, incoordination, poor school performance, uncontrollable movements, and facial grimacing, exacerbated by stress and disappearing with sleep
- Clinical manoeuvres
- demonstration of milkmaid’s grip (irregular contractions of the muscles of the hands while squeezing the examiner’s fingers)
- spooning and pronation of the hands when the patient’s arms are extended
- wormian darting movements of the tongue upon protrusion
- examination of handwriting to evaluate fine motor movements
- Arthralgia (in the absence Migratory Polyarthritis)
- Fever
- ↑ CRP
- ↑ ESR
- prolonged PR (1st degree HB)
DDx
Arthritis
Carditis
Chorea
Rx
Bed rest
Cardiac monitoring
Aspirin
- delay if need polyarthritis to declare to make diagnosis, give paracetamol instead
- 100 mg/kg/day in 4 divided doses PO for 3-5 days
- THEN 75 mg/kg/day in 4 divided doses PO for 4 wk
IF Carditis
- AND cardiomegaly or CHF
- Prednisone 2 mg/kg/day in 4 divided doses for 2-3 wk
- THEN tapering down by 5 mg/day every 2-3 days.
- AND start aspirin with first taper at 75 mg/kg/day in 4 divided doses for 6 wk
- +/- digoxin, fluid and salt restriction, diuretics, and oxygen
- Prednisone 2 mg/kg/day in 4 divided doses for 2-3 wk
For Chorea in isolation, no need for above, instead, sedative options include:
1st line: phenobarbital (16-32 mg every 6-8 hr PO)
2nd line: haloperidol (0.01-0.03 mg/kg/24 hr divided bid PO)
OR chlorpromazine (0.5 mg/kg every 4-6 hr PO)
Primary prevention
- Treat GAS pharyngitis before d9 in at risk individuals
- Benzathine penicillin IM <20kg: 450mg, >20kg 900mg q4w (q3w if recurrence despite prophylaxis)
- with RHD: for life
- after ARF with carditis but no RHD: for 10y or until 21yo which ever is longer
- after ARF without carditis: for 5y or until 21yo is longer
Complications:
Rheumatic Heart Disease (30% of AFR)
- Most common acquired heart disease worldwide
- Genetic predisposition to carditis i.e. if none with first ARF unlikely with subsequent
- Can get insufficiency in ARF but stenosis doesnt appear for years
- IE prophylaxis if prothetic repair (use alternate to penicillin as using for prophylaxis)