Prevention of Rheumatic Fever and Rheumatic Heart Disease
Rheumatic fever and its cardiac complications of carditis and valvular damage are potentially serious consequences of infection with group A β-hemolytic streptococcus (GAS). Despite a dramatic decline in its incidence in the United States associated with the advent of penicillin, rheumatic fever remains a significant cause of preventable cardiac morbidity, especially in developing countries. Moreover, there continue to be periodic outbreaks in the United States, typically in closed populations and in association with international travel to and from regions where untreated GAS infection and rheumatic fever remain prevalent. Prevention entails appropriate application of antibiotic therapy.
Primary prevention depends on timely diagnosis and effective antibiotic treatment of GAS pharyngitis (see Chapter 50 and 220). Vaccination against streptococcal infection may be possible in the future, but current preventive measures depend on discriminating use of antibiotics to treat pharyngitis. Use of antibiotics prophylactically has proven effective for primary prevention during epidemics among closed populations.
Secondary prevention (i.e., prevention of repeat rheumatic fever—the focus of this chapter) depends on antibiotic prophylaxis against GAS infection. Persons with previous rheumatic fever, especially those with cardiac involvement, are at particularly high risk for a recurrence on reexposure to GAS.
The epidemiology of rheumatic fever parallels that of streptococcal infection. Rare in children younger than 5 years of age, it is most common in older children and adolescents. Incidence decreases after adolescence; cases after age 40 years are very rare. There is no clear predilection by gender. Racial differences in the incidence of rheumatic fever exist but disappear when corrected for socioeconomic status—crowded living conditions are an important variable. Crowding may also explain the high incidence in cold climates and during winter months in temperate climates.
All demographic risk factors are heavily outweighed by a previous history of rheumatic fever. The likelihood of an attack after streptococcal infection is at least five times higher among individuals with previous rheumatic fever. Although a definite genetic predisposition has not been proven, an association between certain human leukocyte antigens and rheumatic diseases has been identified, at least among white patients. Heterogeneity in the immune response to a specific streptococcal cell-wall antigen, the group A carbohydrate, has been demonstrated, but predictors of the hyperimmune response associated with the clinical sequelae of rheumatic fever have not been identified.
