RHEUMATIC FEVER AND RHEUMATIC HEART DISEASE

Rheumatic heart disease is now uncommon in westernEurope and North America, but is an important historicalcause of what was once the bulk of valvular heart disease.It is still important in the developing world as a disease ofchildhood and a major cause of heart disease. Its declinein western countries started before the widespread use ofantibiotics, and probably reflects increased standards ofnutrition and hygiene and, possibly, a decline in the virulence and prevalence of Lancefield group A haemolyticstreptococci.

Rheumatic fever and chorea are the exclusive causes ofchronic rheumatic heart disease, in which there is interstitialmuscle fibrosis as well as the heart valve disease.However, some 50% of patients with chronic rheumaticheart disease give no history of either condition.Rheumatic fever develops in about 3% of young peopleexposed to an epidemic strain of (3-haemolytic Lancefieldgroup A streptococcus. These patients usually have pharyngitis,but may have scarlet fever.

After an apparentrecovery they develop fever, sweats, skin rashes, arthritisand, sometimes, cardiac involvement from what appearsto be an autoimmune disease starting 2-4 weeks after theinitial sore throat and lasting 6-8 weeks, but occasionallyas long as 26 weeks. Some patients give no definite historyof an antecedent sore throat.

Following the attack of rheumatic fever, some 70% ofpatients will eventually have evidence of rheumatic valvularheart disease, although the time interval can be as longas 50 years. On the other hand, the valve disease maybecome manifest during the attack of rheumatic fever,especially where regurgitation develops. Rheumatic fevermay be recurrent, and the chances of valve disease increasewith the number of attacks.

Pathology

Although rheumatic fever follows a streptococcal infection,no bacteria are found in the lesions; however, they may still be present in the pharynx. There is an acute inflammatory reaction, with oedema in the affected tissues, and then granulomatous lesions develop in the myocardium(Aschoff nodules). Oedema of the valve cusps isfollowed by verrucous fibrin deposits developing along thelines of apposition of the valve cusps, which eventuallyadhere at the commissures. In the acute illness there is anacute non-bacterial synovitis in the joints, and granulomatamay develop subcutaneously on extensor surfaces of thelimbs and over the Achilles tendons (rheumatic nodules).There is usually a high antistreptolysin O titre, and other antistreptococcal titres may also be high. It is thought thatcross-reactivity between the streptococcal antigens andhost tissue antigens leads to an autoimmune inflammatory process.

Clinical features and diagnosis

The diagnosis of rheumatic fever depends on criteria proposedby Duckett-Jones, two major criteria,or one major and two minor criteria, establish a high probabilityfor the diagnosis.The patient is almost always between the ages of 3 and30 years (usually 5-15); drenching sweats and a prolongedfeverish illness occur, with extremely painful arthritis thatmoves from joint to joint (usually involving large jointssuch as the knee and elbow), which become hot, red,swollen and extremely painful for a few days and thenrecover fully. The flitting arthritis is characteristic, as is theclassic skin rash, erythema marginatum. Subcutaneousnodules may develop after several weeks, usually over theelbows.

Carditis may be pericarditis, myocarditis or, more importantlyfor the eventual appearance of valve disease,endocarditis. All may occur at once as pancarditis. Thepericarditis is similar to any acute pericarditis, withprecordial pain, ECG changes (raised ST segments) andoften an increase in cardiac silhouette on chest X-ray.Myocarditis is manifest by a tachycardia disproportionatefor the degree of pyrexia, gallop rhythm and heart failure;there are also ECG changes, such as prolonged PR intervalor greater degrees of AV block and T-wave flatteningor inversion, and raised serum creatine phosphokinase AV.Death occasionally occurs from myocarditis.

Endocarditis is indicated by transient or changingmurmurs. The classic murmur, which is specific for thecondition, is the Carey Coombs murmur; this is a shortrumbling diastolic murmur indicating mitral valvulitis.

Sydenham’s chorea

Sydenham’s chorea (St Vitus’ dance) is usually a separatedisease entity but, like rheumatic fever, appears to berelated to recent p-haemolytic streptococcal infection andan autoimmune process; occasionally it accompanies therheumatic fever, although it may follow some weeks later.It is characterized by sudden, jerky, purposeless movementsof the face and limbs, such that the child is thoughtto be clumsy and grimacing. Pure chorea, even whenunaccompanied by other evidence of rheumatic fever,is followed by a high incidence of rheumatic valve disease,indistinguishable from that following conventionalrheumatic fever.

Investigation

Laboratory investigations show a raised ESR, C-reactiveprotein and antistreptolysin O titre. Blood cultures arenegative. Throat swab may be positive for p-haemolyticstreptococcus, if the preceding pharyngitis has not beentreated with antibiotic.

Differential diagnosis

As there is no absolute diagnostic test it is extremely common to find patients who have been diagnosed ashaving rheumatic fever on weak evidence, such as a childhoodfever with a few aches and pains and the presenceof a systolic murmur. In one study some 50% of patients with mild congenital heart disease claimed to have had rheumatic fever, suggesting that a child with a heart murmur alone is very likely to be diagnosed as having rheumatic fever during the course of a febrile illness.

Management

Aspirin is traditionally used to control the arthritis andfever; it is used in maximum doses. Where the patient isextremely ill, corticosteroids are commonly used, but thereis no evidence that these reduce the incidence of endocarditisor subsequent development of rheumatic valvular disease.

Prophylaxis

Anyone who has had acute rheumatic fever is at risk ofrecurrence and is usually maintained on phenoxymethylpenicillin(250 mg orally daily, or an i.m. depot preparationof benzathine penicillin) or, if allergic to penicillin, oralsulphonamide, either until the age of 21 or for 5 yearsafter the last attack of rheumatic fever, whichever comeslater.