rheumatic fever

Question 1

definition

Answer 1

An inflammatory multisystem disorder, occurring following group A b-haemolytic streptococci (GAS) infection.

Acute rheumatic fever is an autoimmune disease that may occur following group A streptococcal throat infection. It can affect multiple systems, including the joints, heart, brain, and skin. Only the effects on the heart can lead to permanent illness; chronic changes to the heart valves are referred to as chronic rheumatic heart disease. Without long-term penicillin secondary prophylaxis, acute rheumatic fever can recur, leading to cumulative damage to the cardiac valvular tissue.

Question 2

aetiology

Answer 2

The pathogenic mechanisms remain incompletely understood. 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

symptoms

Answer 3

onset of symptoms 2–5 weeks after GAS infection.

General:
Fever, malaise, anorexia.

Joints:
Painful, swollen, reduced movement/function.

Cardiac:
Breathlessness, chest pain, palpitations.

Question 4

signs/examination

Answer 4

Duckett Jones criteria: Positive diagnosis if at least two major criteria, or one major plus two minor criteria are present.

Major criteria:

• Arthritis: Migratory or fleeting polyarthritis with swelling, redness and tenderness of large joints.
• Carditis: New murmur, e.g. Carey Coombs murmur (mid-diastolic murmur due to mitral valvulitis). Pericarditis, pericardial effusion or rub, cardiomegaly, cardiac failure, ECG changes.
• Chorea (Sydenham’s): Rapid, involuntary, irregular movements with flowing or dancing quality. May be accompanied by 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:

• Pyrexia;
• previous rheumatic fever;
• arthralgia (only if arthritis is not present as major criteria);
• recent streptococcal infection (supported by positive throat cultures or raised antistreptolysin O titre)
• raised inflammatory markers (ESR, CRP or WCC)
• raised PR and QT intervals on ECG (only if carditis not present as major criteria).

Question 5

investigations

Answer 5

Blood: FBC (raised WCC), ESR/CRP (raised), antistreptolysin O titre (raised or rising)

Throat swab: Culture for GAS, rapid streptococcal antigen test.

ECG: Saddle-shaped ST elevation and PR segment depression (features of pericarditis), arrhythmias.

Echocardiogram: Pericardial effusion, myocardial thickening or dysfunction, valvular dysfunction.

• also can do CT chest

Question 6

treatment

Answer 6

primary treatment of streptococcal infection:

• IM benzylpenicillin
• 10 day oral penicillin
• admit and bed rest
• aspirin as needed

Strict bed rest: (around 4 weeks)
Gradual mobilization with clinical improvement.

Anti-inflammatory drugs: High-dose aspirin or, for more severe carditis, consider corticosteroids.

Antibiotics: Eradicate residual streptococcal infection using oral penicillin V for 10 days. Long-term antibiotics to prevent recurrence is necessary (e.g. long-acting benzathine penicillin G intramuscularly every 4 weeks, switch to oral prophylaxis in young adulthood). Prophylaxis in the setting of carditis should continue usually for 10 years. The risk for GAS exposure and severity of valvular disease should then be reviewed.

Carditis: Treat heart failure if present.

Chorea: May be controlled with diazepam or haloperidol.

Valve surgery: If valvular disease cannot be managed with medical therapy alone.

Question 7

other important points

Answer 7

• mitral valve is most commonly involved -> mitral regurg
• pregnancy may precipitate repeat carditis
• long term penicillin treatment is important to prevent chronic rheumatic heart disease

Question 8

complications

Answer 8

Recurrence, may be precipitated by streptococcal infection, more common in patients with residual cardiac damage.

Chronic rheumatic valvular disease: scarring, deformation and dysfunction (usually mitral or aortic) after 10–20 years; more common in those with carditis as part of acute rheumatic fever.

Question 9

prognosis

Answer 9

Acute rheumatic fever may last up to 3 months if untreated.

males are more likely to develop mitral stenosis.