Rheumatic fever

Question 1

What is rheumatic fever?

Answer 1

An inflammatory multisystem autoimmune disorder, occurring following group A beta-haemolytic streptococci (GAS) infection of the pharynx. Only the effects on the heart can lead to permanent illness.

Question 2

What is the aetiology of rheumatic fever?

Answer 2

Streptococcal pharyngeal infection is required, and genetic susceptibility may be present. 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).

Question 3

What is the epidemiology of rheumatic fever: Age? Where? Gender? Incidence?

Answer 3

Occur mainly in children (5-15 years). More prevalent in developed country. No gender difference. Mean incidence is 19 in 100 000.

Question 4

What are the risk factors for rheumatic fever? (x3)

Answer 4

Poverty, family history, genetic susceptibility.

Question 5

What are the symptoms of rheumatic fever? (x3) When?

Answer 5

• Appear 2-5 weeks after GAS infection.
• General: fever, malaise, anorexia
• Joints: painful, swollen, decreased movement and function
• Cardiac: breathlessness, chest pain, palpitation

Question 6

What are the signs of rheumatic fever? Diagnostic criteria?

Answer 6

• DUCKETT JONES CRITERIA: positive diagnosis if at least two major criteria, or one major plus two minor criteria are present.
• MAJOR CRITERIA:
• Migratory or fleeting arthritis with swelling of large joints;
• Carditis: indicated by new murmur (e.g., Carey Coombs murmur – mid-diastolic murmur due to mitral valvulitis), pericarditis, SOB in severe carditis, cardiac failure, or ECG changes
• Chorea (movement disorder that causes involuntary, irregular, unpredictable muscle movements). Most likely Sydenham’s chorea which occurs as a complication of streptococcal infection. Also presents with inability to maintain protrusion of tongue, milkmaid’s grip, spooning sign (wrist flexion and finger extension when hands extended), and pronator’s sign. Always disappears with sleep.
• Subcutaneous nodules
• Erythema marginatum
• MINOR CRITERIA: pyrexia, previous rheumatic fever, arthralgia (if arthritis not present), recent streptococcal infection, raised ESR/CRP/WCC, raised PR/QT intervals on ECG (if carditis not present on ECG)

Question 7

What does erythema marginatum look like?

Answer 7

Transient erythematous rash with raised edges seen on trunk and proximal limbs, forming crescent or ring-shaped patches.

Question 8

What are the investigations on ECG of rheumatic fever? (x2 and x1)

Answer 8

(These are also the major criteria for diagnosis:) saddle-shaped ST elevation and PR segment depression (features of pericarditis), arrythmias.

Question 9

What are the other investigations for rheumatic fever? (x4)

Answer 9

• FBC show raised WCC, ESR and CRP.
• Rising antistreptolysin O titre in bloods (indicative of recent streptococcal infection)
• Throat swab shows culture for GAS
• Echocardiogram: pericardial effusion, myocardial thickening, valvular dysfunction.

Question 10

What are the cardiac manifestations of rheumatic fever?

Answer 10

RHEUMATIC HEART DISEASE – chronic inflammation with fibrinous repair: mitral valve disease, aortic valve disease, pericarditis, cardiac failure (from valve regurgitation).