A 6-year-old boy is brought to the Emergency Department with a 2-day history of a...

Comprehensive and Detailed Explanation:

Transient synovitis is the most common cause of hip pain and limp in children aged 3–10 years. It is often preceded by a viral infection. Patients appear well, can often bear weight, and have only mild to moderate elevation in inflammatory markers. Radiographs are normal.

Toronto Notes 2023 – Pediatrics, “Limping Child”:

“Transient synovitis is benign and self-limiting. Presentation includes mild limp, low-grade fever, normal or slightly elevated CRP/ESR, and ability to bear weight.”

MCCQE1 Objectives (Pediatrics > 78-2: Musculoskeletal Disorders):

“Candidates must distinguish between transient synovitis and more serious causes of limping, such as septic arthritis.”

Septic arthritis (A) usually causes inability to bear weight and more significant fever and CRP elevation. Osteomyelitis (B) typically presents with localized tenderness and systemic signs. Bursitis (D) is rare in young children. JIA (E) is chronic.

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