A 7-year-old boy presents with fleeting polyarthritis involving knees and ankles, low-grade fever, and a new pansystolic murmur at the apex. His throat culture is negative, but ASO titer is 640 IU/mL. What is the MOST accurate Jones criterion classification for this presentation?

• A One major (carditis) + one minor (fever) + evidence of GAS infection
• B One major (polyarthritis) + one minor + evidence of GAS infection
• C Probable rheumatic fever — criteria not met
• D Two major criteria: arthritis + carditis ✓

Explanation

According to the revised Jones criteria (AHA 2015), major criteria include: carditis (clinical or subclinical), polyarthritis (in low-risk populations; monoarthritis/polyarthralgia in moderate/high-risk), chorea, erythema marginatum, and subcutaneous nodules. This child has a pansystolic apical murmur indicating mitral regurgitation — a major criterion (carditis) — and migratory polyarthritis — another major criterion. Two major criteria with evidence of preceding GAS infection (elevated ASO titer) satisfy the diagnosis of Acute Rheumatic Fever. He does not need a third finding; two major + evidence of GAS infection is sufficient.

Reference: Ghai Essential Pediatrics, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.