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Suspected septic arthritis of the hip in a child — MSRA MCQ

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HardHip and GroinSuspected septic arthritis of the hip in a childMSRA

A 5-year-old boy is seen in general practice with 14 hours of worsening right knee pain and refusal to walk. He had coryzal symptoms 10 days ago and his parent thinks this may be irritable hip. There has been no trauma. He is pale but alert and interactive. His temperature is 38.1°C, heart rate 118 beats/min and capillary refill time 2 seconds. The knee has no effusion, erythema or focal tenderness and has full passive movement. He holds the right hip flexed and externally rotated. Passive hip internal rotation is markedly restricted and causes severe distress. A pelvis radiograph performed at a minor injuries unit 3 hours earlier was reported as normal. What is the most appropriate immediate management in primary care?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Arrange immediate transfer for emergency paediatric assessment for suspected septic arthritis

Explanation lettering: D = shown as A · A = shown as B · E = shown as C · B = shown as D · C = shown as E

This child requires immediate hospital assessment for suspected septic arthritis. Although a preceding viral illness and his age make transient synovitis superficially plausible, the decisive features are fever, complete refusal to weight-bear and severe painful restriction of passive hip movement. Hip pathology may present as knee pain, so the normal knee examination is localising rather than reassuring. NICE advises considering septic arthritis or osteomyelitis in a febrile child who is not using an extremity or is non-weight-bearing. Septic arthritis needs urgent assessment because treatment commonly requires hospital-based intravenous antibiotics and joint drainage. B is appropriate only for a well, afebrile, weight-bearing child with a convincing working diagnosis of transient synovitis. C risks delaying transfer while awaiting tests; inflammatory markers may support assessment but must not determine whether this child is escalated. D is insufficiently urgent for a possible joint infection, and repeating plain radiography is not the immediate priority. E is unsafe because the child already has red-flag features rather than an uncomplicated, improving post-viral limp.

Reference: NICE NG143: Fever in under 5s: assessment and initial management, recommendation 1.2.24 (2019) — https://www.nice.org.uk/guidance/NG143/chapter/recommendations NHS: Septic arthritis (2024) — https://www.nhs.uk/conditions/septic-arthritis/ NHS: Hip pain in children (irritable hip) (2024) — https://www.nhs.uk/symptoms/hip-pain-children-irritable-hip/