Acute rheumatic fever (ARF) is a systemic, immune-mediated disease that is triggered by pharyngeal infection with group A streptococci (GAS). Fever, migratory polyarthritis, and carditis are the most common clinical manifestations. ARF is most frequent among 5–15 year olds with a declining incidence in adults. It is extremely rare in children under age 3, prompting speculation that more than one GAS infection is needed before ARF can develop. ARF is not considered a sequela of cutaneous GAS infection.
The pathogenesis of ARF is not clearly understood but appears to involve an immune response to group A streptococcal antigens that then cross-reacts with human tissue through molecular mimicry. Strains of GAS differ in their ability to trigger ARF, and changes in the prevalence of rheumatogenic strains can affect the incidence of ARF. Recent evidence supports the conclusion that ARF has declined in the United States over the past decades largely because of a decline in rheumatogenic types of GAS causing pharyngitis.
The reported attack rate of ARF among patients with untreated GAS pharyngitis is 0.4–3% in epidemic circumstances, with a much lower rate endemically. Genetic factors appear to influence the person’s susceptibility to ARF. Observational studies in the 19th century recognized familial tendencies to develop ARF, and in the early 1940s, studies showed familial clustering of the disease, with greatest risk occurring in children if both parents had rheumatic heart disease. Genetic susceptibility to develop ARF has been characterized as autosomal recessive or autosomal dominant with variable penetrance and has been linked with HLA types. Significant increases in the frequency of DRB1*0701, DR6, and DQB1*0201 confer susceptibility to rheumatic fever in several international studies. Monozygotic twins, however, are not usually concordant for ARF, indicating that there are also important environmental factors involved in the pathogenesis of the disease.
In 1944, Dr. T. Duckett Jones developed diagnostic criteria for ARF—the “Jones criteria”—based on his observations of hundreds of patients. The Jones criteria have been revised several times, most recently in 1992 (Table 52–1), and continue to form the basis for the clinical diagnosis of ARF. Exceptions to these criteria include patients who present with chorea or indolent carditis; these patients often do not fulfill the requirement for evidence of antecedent GAS infection because their antistreptococcal antibody levels usually have returned to normal at the time of presentation.
Table 52–1. Modified Jones Criteria for Diagnosis of Acute Rheumatic Fever.a ||Download (.pdf)
Table 52–1. Modified Jones Criteria for Diagnosis of Acute Rheumatic Fever.a
- Major criteria
- Erythema marginatum
- Subcutaneous nodules
- Minor criteria
- Elevated acute phase reactant (C-reactive protein or erythrocyte sedimentation rate)
- Prolonged PR interval on electrocardiogram
- Supporting evidence of antecedent group A streptococcal infection
- Positive throat culture or rapid antigen test
- Elevated or rising streptococcal antibody titer