Infections caused by group A β-hemolytic Streptococcus (Streptococcus pyogenes) are unusual in that they have been associated with nonsuppurative complications, acute rheumatic fever (ARF), and acute glomerulonephritis. These distinct clinical entities are not related to toxic effects of the organism and follow the infections by an interval during which immunologic mechanisms are triggered. Table 152.1 compares some features of two clinical syndromes. This chapter describes clinical manifestations and treatment for these sequelae.

ACUTE RHEUMATIC FEVER

ARF is a multisystem collagen-vascular disease that follows untreated or undetected group A streptococcal pharyngitis in 1% to 3% of persons. It is seen most commonly in children ages 5 to 17 and is associated with a genetic predisposition. There also appear to be strains of S. pyogenes more likely to be implicated in this condition (see Table 152.1).

The diagnosis of ARF is made clinically and is based on the modified Jones criteria (Table 152.2). The presence of two major or one major and at least two minor criteria suggests the diagnosis. Recent infection with S. pyogenes also must be suggested by either isolation of the organism from the throat or serologic evidence in the form of elevation of antistreptolysin-O, antihyaluronidase, or antideoxyribonuclease B titers. The exception to this rule is chorea, which becomes manifest 2 to 6 months after infection, by which time evidence of a recent streptococcal infection may be lacking.