Rheumatology
23.1 Acute Rheumatic Fever (ARF)
Cause: Group A hemolytic (rarely non-hemolytic) Streptococcus, with presence of m-protein; post-streptococcal, upper respiratory infection × 2-3 wks, but bacteria must still be present.
Epidem: Children peak incidence between 5-15 yr of age (J Infect 1998;36:249); female:male 3:1; incidence of approximately 0.3:100,000 (Acta Med Scand 1988;224:587); see Pharyngitis p358.
Pathophys: Autoimmune theories with cross reacting antibodies between Group A strep and human tissues [such as T-cells (Clin Exp Immunol 1999;116:100)], but does not explain why only strep pharyngitis may go onto ARF.
Jones criteria (Ped Ann 1999;28:9): for diagnosis need 2 major criteria or 1 major plus 2 minor criteria, and then also a pos ASO titer or culture or h/o scarlet fever.
Major criteria: carditis; polyarthritis; erythema marginatum; sc nodules; chorea.
Sx: Sore throat; fever; arthralgias—although transitory (Indian J Peds 1988;55:9).
Si: Erythema marginatum—associated with carditis; murmurs (valvular or non-valvular) which are associated with pericarditis; sc nodules at bony prominences that are associated with carditis; pneumonitis; serositis; polyarthritis of large joints; Sydenham’s chorea may follow other signs (or symptoms) by weeks or months.
Crs: Less than 12 wks in approximately 90%; approximately 95% of those with murmurs appear by 2 wks of symptom onset.
Cmplc: Chronic cardiac valve disease; mitral regurgitation with Jaccoud’s arthritis (ulnar deviation that can voluntarily correct); transient glomerulonephritis.
Diff Dx: Post-streptococcal reactive arthritis (J Intern Med 1999;245:261); Familial Mediterranean fever (Clin Rheumatol 1999;18:446); septic arthritis; infective endocarditis; cat scratch disease; RA; immune complex disease; Still’s disease; pustular psoriasis; dermatomyositis; inflammatory bowel disease; sarcoidosis; systemic lupus erythematosus (SLE).
Lab: CBC with diff; ESR; metabolic profile; UA; throat culture, if still inflamed; ASO titer or streptozyme test; consider anti-DNAase or anti-streptodornase titer; EKG.
X-ray: Look for interstitial pneumonitis.
Emergency Management:
PCN G 25-50 mg/kg qd divided bid po for peds, 500 mg po bid for adults; PCN G benzathine and procaine (bicillin C-R, or bicillin C-R 900/300) im single dose—this will be extended for years of prophylaxis in those with carditis.Related posts:
Full access? Get Clinical Tree
