Acute Rheumatic Fever: The Daily PANCE Blueprint
A 10-year-old boy is brought in with fever and joint pain. Three weeks ago he had a sore throat that was never cultured or treated. Over the past four days, pain and swelling moved from his right knee to his left ankle to his left wrist. On exam he has a new holosystolic murmur at the apex radiating to the axilla, and several firm, painless nodules over his elbows. ESR and C-reactive protein are elevated, and the antistreptolysin O titer is high. Which of the following is the most likely diagnosis?
A. Juvenile idiopathic arthritis
B. Acute rheumatic fever
C. Septic arthritis
D. Systemic lupus erythematosus
E. Reactive arthritis
Answer and topic summary
The answer is B. Acute rheumatic fever
Migratory polyarthritis, a new mitral murmur, and subcutaneous nodules two to four weeks after an untreated streptococcal pharyngitis is acute rheumatic fever — a post-infectious immune response in which antibodies against group A Streptococcus cross-react with host tissue. Diagnosis uses the revised Jones criteria: evidence of preceding strep infection plus either two major criteria or one major and two minor. The major criteria are the mnemonic JONES — Joints (migratory polyarthritis), O for carditis (the heart, and the only manifestation that causes permanent damage), Nodules (subcutaneous), Erythema marginatum, and Sydenham chorea. This boy has three. Treatment is penicillin to eradicate the organism, anti-inflammatories for the arthritis, and — critically — long-term secondary prophylaxis with penicillin to prevent recurrence and rheumatic heart disease. Septic arthritis is monoarticular and does not migrate; juvenile idiopathic arthritis is persistent rather than migratory and lacks the strep history.
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