A 6-year-old girl develops acute onset arthritis of both knees and ankles with fever and a salmon-pink evanescent rash that appears and disappears with temperature spikes. Investigations show elevated ESR, CRP, ferritin >1000 ng/mL, and leukocytosis. ANA and RF are negative. What is the MOST likely diagnosis?
- A Rheumatic fever
- B Systemic Lupus Erythematosus
- C Systemic Juvenile Idiopathic Arthritis (sJIA) ✓
- D Reactive arthritis
Correct answer: C. Systemic Juvenile Idiopathic Arthritis (sJIA)
Explanation
The combination of quotidian (daily) high-spiking fever, evanescent salmon-pink rash appearing with fever spikes, arthritis, and markedly elevated ferritin in a seronegative (RF-/ANA-) child defines Systemic Juvenile Idiopathic Arthritis (Still's disease). Ferritin >500 ng/mL is a key diagnostic clue, and extremely elevated ferritin (>10,000) raises concern for macrophage activation syndrome, the most serious complication. Treatment includes NSAIDs, steroids, and IL-1/IL-6 inhibitors (anakinra, tocilizumab) for refractory disease.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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