Rheumatic Fever
An acute disease involving many structures in the body, rheumatic fever particularly afflicts the joints and the heart. Whereas rheumatic disease of the joints heals without aftereffects, involvement of the heart may produce permanent damage to the heart valves; that damage is sometimes immediately apparent, but it may also go undetected for many years. Attacks of rheumatic fever vary in severity; it may manifest itself as an acute, serious disease associated with high fever or appear as minor swelling and pain in the joints. Rheumatic fever is a disease of childhood and in most cases affects persons between the ages of four and twenty.
Though resembling an infectious disease, rheumatic fever is not caused directly by a microorganism. Rather, the body reacts to certain strains of streptococcus (a common bacterium responsible for many different infections, including sore throat) in persons hypersensitive to the microorganism (a process akin to allergy).
The epidemiology of rheumatic fever is one of the more interesting phenomena in contemporary medicine. The prevalence of the disease was high in the United States and other Western countries until the 1950s. Since then its incidence has declined steadily; the cause of this shift is not well understood. By contrast, there has been a dramatic increase in the incidence (or perhaps recognition) of rheumatic fever in third-world countries. As a consequence, rheumatic fever is rarely encountered in the developed countries, whereas in the developing countries of Latin America and Africa and in India it has become the principal cause of heart disease.
A typical attack of rheumatic fever is disabling, producing painful swelling of the large joints—the knees, elbows, and hips—usually migrating from joint to joint and affecting only one at a
time. It usually lasts one to four weeks but occasionally persists for months. Involvement of the heart is common but, more often than not, inconspicuous and difficult to detect. Other organs may also be involved, such as the lungs, kidneys, and brain (producing chorea, or uncoordinated movements).
Involvement of the heart appears as carditis (also referred to as pancarditis), which consists of rheumatic changes in the three layers of the heart—the endocardium (valves), the myocardium (heart muscle), and the pericardium. Although carditis usually does not affect the function of the heart or produce symptoms, it occasionally brings on serious, even fatal, conditions, such as heart failure, severe incompetence of valves, or large pericardial effusion. Characteristically, changes in the myocardium and pericardium heal without any aftereffects. Rheumatic disease of the valves, however, produces small, wartlike lesions that often initiate a chronic process leading after many years to serious valve disease. The principal damage to heart valves occurs as a result of the healing and scarring of the acute changes. Stenosis of the valve is caused by adhesion between leaflets, incompetence by shrinking of the scarred valve. Thus chronic valve disease is not a direct continuation of the acute disease but usually appears after a long period of apparent complete recovery.
Rheumatic fever has a tendency to recur: a child hypersensitive to streptococcus may suffer an attack each time it is infected. Hence the standard treatment is prophylactic administration of an antibiotic (usually penicillin) to prevent streptococcal infection for many years after the first attack. Recurrence of rheumatic fever increases the severity of valvular disease. In the developing countries, where penicillin prophylaxis is difficult to enforce, children may have yearly attacks of rheumatic fever and develop serious valvular disease at a young age. Thus, though in most cases rheumatic fever is a self-limiting disease, its effect on the cardiac valves may produce disabling heart disease decades later.