rheumatic fever Flashcards
definition of rheumatic fever
An inflammatory multisystem disorder, occurring following group A b-haemolytic streptococci (GAS) infection
aetiology of rheumatic fever
not fully understood
need B haemolytic streptococcal pharyngeal infection and genetic susceptibility
Molecular mimicry is thought to play an important role in the initiation of the tissue injury (antibodies directed against GAS antigens cross-react with host antigens in valve tissue = possible permanent damage to heart valves).
RF for rheumatic fever
poverty
overcrowded living quarters
FH
D8/17 B cell Ag positivity
HLA association
genetic susceptibility
indigenous populations: Aboriginal Australian, Asian, and Pacific Islanders
epidemiology of rheumatic fever
5-15yrs
most common in the far east, middle east, eastern europe and south america
incidence 19/100000
reducing incidence in west, high in non-western countries
recur unless prevented
sx of rheumatic fever
2-5 weeks after infection
fever
malaise
anorexia
joints: painful, swollen, reduced movement/function
cardiac - breathlessness, chest pain, palpitations
signs of rheumatic fever
Duckett Jones criteria: Positive diagnosis if evidence of recent strep infection, and at least two major criteria, or one major plus two minor criteria are present.
evidence of gp A B-haemolytic strep infection
+ve throat culture - usually -ve by the time symptomatic
rapid strep ag test +ve
elevated/rising strep ab titre (eg anti-streptolysin O (ASO) or DNase B titre).
recent scarlet fever
major criteria for rheumatic fever
arthritis: migratory or fleeting polyarthritis with swelling, redness and tenderness of large joints
carditis: new murmer eg Carey Coombs murmur (mid-diastolic murmur due to mitral valvulitis), pericarditis, pericardial effusion rub, cardiomegaly, cardiac failure
chorea (Sydenham’s): rapid involuntary irregular movements, with flowing or dancing quality. Slurred speech. More common in females
nodules - Small firm painless subcutaneous nodules seen on extensor surfaces, joints and tendons.
Erythema marginatum (20% cases): Transient erythematous rash with raised edges, seen on trunk and proximal limbs. They may form crescent- or ring-shaped patches.
minor criteria for rheumatic fever
pyrexia
previous rheumatic fever
arthralgia (only if arthritis not present as major criteria)
recent strep infection (+ve throat cultures or raised antistreptolysin O titre)
raised inflammatory markers - ESR, CRP, WCC
raised PR, QT intervals on ECG (only if carditis not present as major criteria)
Ix for rheumatic fever
blood - FBC (raised WCC), ESR/CRP raised, high or rising antistreptolysin O titre
throat swab - culture for GAS, rapid streptococcal antigen test
ECG - Saddle-shaped ST elevation and PR segment depression (features of pericarditis), arrhythmias.
echo - Pericardial effusion, myocardial thickening or dysfunction, valvular dysfunction.
mx of rheumatic fever
- monoarthritis in unconfirmed r fever - analgesia
- possible r fever - secondary prophylaxis (benzathine benzylpenicillin) every 4 wks
- confirmed:
- abx (benzathine benzylpenicillin) one off
- with arthritis - NSAID/aspirin
- HF - diuretic +- ACEi
- with AF - amiodarone/digoxin
- with valve leaflet/cordae tendineae rupture - emergency valve surgery
- severe/disabling chorea - consider anticonvulsants
everyone needs IM benzathine benzylpenicillin every 4 wks after acute phase
pt education for rheumatic fever
- good oral hygeine - inform dr/dentist before procedure, need abx cover
- importance of secondary prevention
- rx of sore throat early - non-penicillin Abx if on penicillin prophylaxis
complications of rheumatic fever
rheumatic heart disease
* mitral valve
follow up for rheumatic fever
ESR and CRP weekly until normalise
echo after 1 mo
if carditis -
* review by GP at 6mo intervals
* annual echo
