Rheumatic Fever Flashcards
What is rheumatic fever?
An inflammatory multisystem disorder, occurring following group A beta-haemolytic streptococci (GAS) infection (ALWAYS CAUSED BY INFECTION OF PHARYNX NOT HEART!!)
AI disease
Describe the aetiology of rheumatic fever
UNKNOWN
Streptococcal pharyngeal infection +/- genetic susceptibility triggers RF 2-4 weeks later in the susceptible 2% of the population
Molecular mimicry involved in initiation of tissue injury (antibodies against GAS antigens cross-react with host-antigens)
List 5 risk factors for rheumatic fever
Genetic susceptibility (HLA class II) Age (4-9 yrs) F > M Seasonality (winter + spring peak) Economic factors e.g. poverty, urban environ + crowding
Describe the epidemiology of rheumatic fever
Used to have outbreaks before penicillin, esp in children
Common in developing countries but increasingly rare in the West
Peak incidence between 5- 15 years
Mean incidence 19/100,000
When does onset of symptoms start in RF? List 3 general symptoms of rheumatic fever
2-5 weeks after pharyngeal GAS infection Recent sore throat or scarlet fever Malaise Fever Anorexia
Give 2 symptoms affecting the joints in rheumatic fever
Painful, swollen joints
Reduced movement/ function
List 3 cardiac symptoms in rheumatic fever
Breathlessness
Chest pain
Palpitations
What criteria are used to assess rheumatic fever?
Revised Jones criteria.
Evidence of recent strep infection + 2 major criteria OR 1 major + 1 minor criteria
Evidence of GAS infection:
+ve throat culture: but usually -ve by time sx occur
Rapid strep antigen test +ve
Elevated/rising strep antibody titre
Recent scarlet fever
List 5 signs falling under major criteria of rheumatic fever
CASES
CARDITIS: tachycardia, murmurs (mitral/ aortic regurg), pericardial rub, cardiomegaly, conduction defects, signs of cardiac failure
ARTHRTIS: usually larger joints (antibodies against joints)
Subcutaneous nodules: small firm painless nodules seen on extensor surfaces, joints + tendons
ERYTHEMA MARGINATUM: rash with red, raised edges + clear centre mainly on trunk + proximal limbs (antibodies against skin)
SYDENHAMs CHOREA: rapid, involuntary, irregular movements with flowing/ dancing quality (antibodies against brain) AKA servitus dance
List 5 signs falling under minor criteria of rheumatic fever
PRAPP
Pyrexia
Raised ESR/CRP
Arthralgia (only if arthritis not present as major criteria)
Prolonged PR interval (only if carditis not present as major criteria)
Previous rheumatic fever
Look out for features of mitral + aortic stenosis. If hear a MS or AS, ask whether they had RF when they were younger
What bloods should be taken for rheumatic fever?
WCC elevated
ESR/CRP elevated
Rising antistreptolysin O titre
What can be performed with a throat swab for rheumatic fever?
Culture for GAS
Rapid streptococcal antigen test
What is seen on histology in rheumatic fever?
Aschoff bodies (granuloma with giant cells) Anitschkow cells (enlarged macrophages with ovoid, wavy, rod-like nucleus)
What is seen on ECG in rheumatic fever?
saddle-shaped ST elevation + PR segment depression (features of pericarditis)
Arrhythmias
(Prolonged PR interval is a minor criterion of acute RF)
What is seen on CXR in rheumatic fever?
Chamber enlargement
Congestive cardiac failure
