Rheumatic fever and rheumatic heart disease
A systemic inflammatory disease of childhood, acute rheumatic fever develops after infection of the upper respiratory tract with group A beta-hemolytic streptococci.
Rheumatic fever principally involves the heart, joints, central nervous system, skin, and subcutaneous tissues. It commonly recurs.
The term rheumatic heart disease refers to the cardiac involvement of rheumatic fever—its most destructive effect. Cardiac involvement develops in up to 50% of patients and may affect the endocardium, myocardium, or pericardium during the early acute phase. It may later affect the heart valves, causing chronic valvular disease.
The extent of damage to the heart depends on where the disorder strikes. Myocarditis produces characteristic lesions called Aschoff’s bodies (in the acute stages) and cellular swelling and fragmentation of interstitial collagen, leading to formation of a progressively fibrotic nodule and interstitial scars. Endocarditis causes valve leaflet swelling, erosion along the lines of leaflet closure, and blood, platelet, and fibrin deposits, which form beadlike vegetation. It most commonly strikes the mitral valve in females and the aortic valve in males. In both, it affects the tricuspid valves occasionally and the pulmonary valve only rarely.
Long-term antibiotic therapy can minimize the recurrence of rheumatic fever, reducing the risks of permanent cardiac damage and valvular deformity.
Although rheumatic fever tends to be familial, this tendency may merely reflect contributing environmental factors.
Pediatric pointerIn lower socioeconomic groups, the incidence of rheumatic fever is highest in children between ages 5 and 15, probably as a result of malnutrition and crowded living conditions. Rheumatic fever strikes most often during cool, damp weather in the winter and early spring. In the United States, this disease is most common in the northern states.
Causes
Rheumatic fever appears to be a hypersensitivity reaction in which antibodies produced to combat streptococci react and produce characteristic lesions at specific tissue sites. How and why group A streptococcal infection initiates the process are unknown. Because few people infected with Streptococcus ever contract rheumatic fever (about 0.3%), altered host resistance probably is involved in rheumatic fever’s development or recurrence.
Complications
In many patients, rheumatic fever’s long-term effects destroy the mitral and aortic valves. Their malfunction leads to severe pancarditis and occasionally produces pericardial effusion and fatal heart failure. Of the patients who survive this complication, about 20% die within 10 years.
Assessment
Nearly all affected patients report having a streptococcal infection a few days to 6 weeks before being diagnosed with rheumatic fever. They usually have a recent history of low-grade fever that spikes to at least 100.4° F (38° C) late in the afternoon, unexplained epistaxis, and abdominal pain.
Most patients complain of migratory joint pain (polyarthritis). Swelling, redness, and signs of effusion usually accompany such pain, which most commonly affects the knees, ankles, elbows, and hips.
If the patient has pericarditis, he may complain of sharp, sudden pain that usually starts over the sternum and radiates to the neck, shoulders, back, and arms. The pain commonly is pleuritic, increasing with deep inspiration and decreasing when the patient sits up and leans forward. (This position pulls the heart away from the diaphragmatic pleurae of the lungs.) The pain may mimic that of myocardial infarction.
A patient with heart failure caused by severe rheumatic carditis may complain of
dyspnea, right upper quadrant pain, and a hacking, nonproductive cough.
dyspnea, right upper quadrant pain, and a hacking, nonproductive cough.
Inspection may reveal skin lesions such as erythema marginatum, a nonpruritic, macular, transient rash. The lesions are red with blanched centers and well-demarcated borders. They typically appear on the trunk and extremities.
Near tendons or the bony prominences of joints, you may notice subcutaneous nodules that are firm, movable, nontender, and about 3 mm to 2 cm in diameter. They occur especially around the elbows, knuckles, wrists, and knees and less often on the scalp and backs of the hands. These nodules persist for a few days to several weeks and, like erythema marginatum, often accompany carditis.
You may notice edema and tachypnea if the patient has left ventricular failure.
Up to 6 months after the original streptococcal infection, you may note transient chorea. Mild chorea may produce hyperirritability, a deterioration in handwriting, or inability to concentrate. Severe chorea causes poor muscle coordination, weakness, and purposeless, nonrepetitive, involuntary muscle spasms and speech disturbances. Chorea resolves with rest and causes no residual neurologic damage.
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