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Suspected septic arthritis of the native hip — MSRA MCQ

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HardHip and GroinSuspected septic arthritis of the native hipMSRA

A 62-year-old man presents to general practice with 18 hours of rapidly worsening right groin pain. Five days ago he had an ultrasound-guided intra-articular corticosteroid injection for symptomatic hip osteoarthritis. He has type 2 diabetes (HbA1c 71 mmol/mol) and takes methotrexate for psoriasis. He is unable to weight-bear. His temperature is 37.7°C, heart rate 96 beats/min, blood pressure 134/78 mmHg and respiratory rate 16 breaths/min. The hip is held flexed and externally rotated; both active and passive movement are severely painful and restricted. There is no overlying erythema. CRP is 112 mg/L and neutrophils 10.9 × 10⁹/L. A pelvis radiograph shows unchanged moderate osteoarthritis. He has previously had podagra and asks whether this could be gout. What is the most appropriate immediate management plan?

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

Reveal the answer and explanation

Correct answer: E — Arrange emergency hospital assessment for blood cultures and urgent orthopaedic-led hip aspiration before antibiotics, provided he remains clinically stable

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

This presentation must be managed as suspected septic arthritis of the native hip. The decisive features are rapid onset of severe deep joint pain, inability to weight-bear, marked pain on passive movement, inflammatory-marker elevation, and increased susceptibility following an invasive joint procedure in a person with poorly controlled diabetes and immunomodulatory treatment. A normal or unchanged plain radiograph does not exclude septic arthritis. D is best because hip aspiration is not a routine primary-care procedure: urgent orthopaedic assessment is required for aspiration, culture and potential drainage. In a clinically stable patient, blood cultures and joint fluid should be obtained before antibiotics to maximise microbiological yield; aspirate should also be examined for crystals. Previous podagra does not safely establish gout as the cause of this acute monoarthritis. A is unsafe because gout remains a differential diagnosis but must not delay exclusion of joint infection. B delays definitive assessment; ultrasound may identify an effusion and assist aspiration, but should be organised within the emergency pathway rather than as an outpatient diagnostic step. C is appropriate if the patient is septic or unstable, when antibiotics must not be delayed, but this stable patient should have cultures and aspiration obtained first where feasible. E may be appropriate after trauma or when occult fracture remains the leading diagnosis, but the inflammatory presentation makes septic arthritis the immediate priority.

Reference: Acute Monoarthritis (Reviewed 1 May 2025) — https://www.rightdecisions.scot.nhs.uk/nhs-tayside-refguide/medicine/rheumatology/acute-monoarthritis/ Septic arthritis (Reviewed 24 April 2024) — https://www.rightdecisions.scot.nhs.uk/antimicrobial-prescribing-nhs-lothian/body-systems/bone-and-joint-infections/septic-arthritis/ Septic Arthritis/Osteomyelitis (Current page accessed 15 August 2026) — https://www.rightdecisions.scot.nhs.uk/antimicrobial-prescribing-nhs-grampian-orkney-shetland/hospital-guidance-for-adults/musculoskeletal-joint/septic-arthritisosteomyelitis/