Rheumatic fever

Definition

Recurrent inflammatory disease affecting the heart; it occurs following a streptococcal infection.

Incidence

1 in 100,000 United Kingdom/United States population per year; incidence has declined over the last 100 years.

Age

First attack usually 5–15 years.

Sex

M = F

Geography

Common in Middle and Far East, South America and Central Africa, declining in the West.

Aetiology

Cell-mediated autoimmune reaction following a pharyngeal infection with Î²-haemolytic streptococcus of Lancefield group A (Streptococcus pyogenes). Risk factors for streptococcal infection include poverty and over-crowded conditions, the reduction of which, together with the increased use of antibiotics, may well explain the decline in developed countries.

Pathophysiology

It appears that antistreptococcal antibodies crossreact with antigens in connective tissues, particularly of endotheliallined tissues such as blood vessels, endo-cardium, pericardium and synovial membranes. All three layers of the heart may be affected (pancarditis); the characteristic lesion is the Aschoff ’s nodule (see in section Microscopy below).

Pericarditis: Nodules are seen within the pericardium associated with an inflammatory pericardial effusion.

Myocarditis: Nodules develop within the myocardium associated with inflammation. This may result in decreased myocardial function and left ventricular failure.

Endocarditis: Nodules may form anywhere on the endocardium, but tend to cause more damage and erosion when they occur within the heart valves as vegetations. These may result in an acute disturbance of valve function.

Recurrent attacks may occur over many years.

Clinical features

There may be a history of pharyngitis in up to 50% of patients. The diagnosis is made on two or more major manifestations or one major plus two or more minor manifestations (Duckett Jones criteria).

Major manifestations may be remembered as PACES:

·        Pancarditis presents with new or changed cardiac murmurs (due to endocarditis) and the ECG changes of myocarditis and pericarditis. A pericardial friction rub may be audible due to pericarditis.

·        Arthritis affecting multiple large joints that ranges in severity from mild aches to severe non-destructive arthritis, which may occur sequentially in different joints (flitting arthritis).

·        Chorea (Sydenham’s chorea) is characterised by jerky non-repetitive movements associated with reduced muscle tone. Postpuberty this manifestation is confined to females.

·        Erythema marginatum is an erythematous rash composed of red, well-circumscribed lesions with a pale centre over the trunk and limbs, which appear and disappear over a matter of hours.

·        Subcutaneous painless nodules may be palpated over the extensor surfaces, tendons, joints and bony prominences.

Minor manifestations: pyrexia, raised ESR/CRP, arthralgia, previous rheumatic fever, long PR interval on ECG and a leucocytosis. Non-specific symptoms include malaise and loss of appetite.

Evidence of a preceding streptococcal infection such as positive throat culture, elevated antistreptolysin O titre or other streptococcal antibodies is suggestive.

Macroscopy

Fibrinous vegetations form on the edges of the valve leaflets with associated oedema. Valve leaflets may fuse and scar, particularly affecting the mitral and aortic valves.

Microscopy

Aschoff ’s nodules are granulomatous lesions composed of a necrotic core of degenerated collagen surrounded initially by macrophages and lymphocytes. Over time these cells are replaced by histiocytes, which may be mult-inucleated. Nodules heal by scarring.

Complications

More than 50% of patients with acute rheumatic carditis will develop chronic rheumatic valve disease 10–20 years later, particularly mitral and aortic stenosis. These may be complicated by atrial fibrillation, heart failure, infective endocarditis and mural thrombus formation.

Investigations

·        Cultures of blood and tissues are sterile by the time rheumatic fever manifests, but throat swabs may be positive and there may be serological evidence (raised antistreptolysin O titre or other antistreptococcal antibodies).

·        Non-specific indicators of inflammation, such as a raised ESR and leucocytosis.

·        ECG shows prolonged PR interval and non-specific T wave changes. Pericarditis may initially result in widespread ST elevation, concave upwards. After a few days ST returns to the isoelectric point and there is T wave inversion.

·        Echocardiography is used to examine the function of the cardiac valves and may be helpful in diagnosing pancarditis.

Management

·        Patients with a clinical diagnosis of rheumatic fever should be treated with benzylpenicillin regardless of culture results.

·        Pain, fever and inflammation are treated with high-dose aspirin. Carditis may be treated with a course of high-dose corticosteroids.

·        Patients may require treatment for heart failure and chorea may respond to haloperidol.

·        Following recovery patients should receive prophy-lactic penicillin for at least 5 years after the last at-tack or until the age of 20 years, whichever is the later.

Prognosis

Although symptomatic improvement occurs with treatment, therapy does not appear to prevent subsequent valve damage.