Cause:Group A hemolytic streptococcus (rarely group A nonhemolyticNejm 1971;284:750), type irrelevant but presence of m-protein probably key, eg, nephrogenic strains (esp skin ones) lack m-protein and never lead to ARF (Nejm 1970;283:561). Poststrep infection × 2-3 wk, though bacteria must still be present. Genetic susceptibility in some populations? (Bull Rheum Dis 1993;42:5)
Pathophys:Autoimmune theories, like strep A and humans share antigens, or at least haptens, so strep infections develop cross-reacting antibodies. But not the complete explanation, as L. Weinstein points out, because only strep pharyngitis causes ARF, not strep infections elsewhere in body unlike AGN
(Nejm 1991;325:783) Children, peak incidence age 5-15 yr; female/male = 3:1; incidence = 61/100 000/yr in NYC (Jama 1973;224:1593), marked decrease since use of penicillin (Nejm 1988;318:280), increased × 3 among the poor.
Sx:
Jones criteria to make the dx requires 2 major criteria, or 1 major + 2 minor, + positive ASO titer or culture or h/o scarlet fever; major criteria = carditis, polyarthritis, erythema marginatum, subcutaneous nodules, chorea; minor criteria = fever, arthralgias, distant h/o ARF, elevated wbc ESR or CRP, long PR interval or other EKG abnormalities. Members of same family tend to have same major sx (Nejm 1968;278:183)
Arthralgias, transitory; Sydenhams chorea, may follow other si and sx by weeks or months
Si:
Chronic cardiac valve disease; mitral regurgitation with Jaccouds arthritis (ulnar deviation, which pt can voluntarily correctAnn IM 1972;77:949); transient glomerulonephritis (Ann IM 1981;94:322)
Lab:
Hem:Elevated ESR
Noninv:EKG: PR interval increased
Serol:Streptozyme test (Med Let 1974;16:41); ASO (antistreptolysin O) >400 Todd U, means had -strep, <125 U means didnt, 80% sensitivity; anti-DNAase titer; antistreptodornase titer
Xray:Chest shows interstitial, nonbacterial pneumonitis
Rx:
Preventive: penicillin as pen V 250 mg po bid in adults or qd in children; or sulfasoxazole, or benzathine penicillin im q 1 mo most effective (New Eng J Med 1971;285:646)
Table 18.1 Rx of Acute Rheumatic Fever
If No Murmur | If Severe Carditis | If Sick/No Murmur | |
---|---|---|---|
Penicillin | Yes | Yes + years of prophylaxis | Yes |
ASA | Yes | Yes | Yes |
Steroids | No | Yes | Optional unless has pneumonia then should rx (Weinstein) |