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Clenched-fist human bite with suspected metacarpophalangeal joint penetration — MSRA MCQ

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HardSoft Tissue InjuryClenched-fist human bite with suspected metacarpophalangeal joint penetrationMSRA

A 29-year-old man attends a GP-led urgent treatment centre 16 hours after punching another person in the mouth. He initially thought he had sustained a superficial graze over the dorsum of his dominant right hand. He washed the area under running water but did not seek care. He now has increasing pain and swelling around the third metacarpophalangeal (MCP) joint. He is afebrile and systemically well. There is a 3 mm full-thickness puncture wound which lies directly over the third MCP joint when the hand is clenched; the base cannot be visualised. Active finger extension is preserved, but passive MCP flexion is markedly painful. Capillary refill, sensation and flexor function are normal. Hand radiographs show no fracture or retained tooth fragment. His tetanus immunisation is complete and he has no drug allergies. What is the most appropriate management now?

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Correct answer: D — Irrigate the wound, leave it open, give oral co-amoxiclav, and arrange immediate hospital assessment by the hand surgical team

This is a clenched-fist human bite (“fight bite”) with likely penetration of the third MCP joint. The apparently small dorsal wound is misleading: it overlies the joint when the fist is clenched, and painful passive MCP movement raises concern for inoculation of the joint or adjacent deep structures. A normal radiograph excludes neither joint penetration nor early septic arthritis; it merely reduces concern about fracture or a retained tooth fragment. NICE recommends hospital referral for a penetrating bite involving a joint, tendon, muscle, nerve, bone or vascular structure. This patient also has evolving local inflammatory symptoms, so antimicrobial treatment is required rather than prophylaxis alone. Co-amoxiclav is NICE first-choice oral treatment in adults who can take oral medication, while urgent surgical assessment is needed for possible exploration, washout and definitive antimicrobial route/duration decisions. The wound should not be primarily closed. A is inappropriate because human bites to the hand should not be sutured and a 3-day course is prophylaxis rather than treatment. B provides appropriate oral antibiotic duration for many infected bites, but dangerously omits urgent assessment of probable joint involvement. C uses inadequate empirical coverage for a human bite and delays definitive care. E overlooks the high-risk mechanism, location and examination finding.

Reference: NICE NG184: Human and animal bites: antimicrobial prescribing — Recommendations (Published 4 November 2020; checked 15 August 2026) — https://www.nice.org.uk/guidance/ng184/chapter/Recommendations NICE NG184: Human and animal bites: antimicrobial prescribing — Referral and seeking specialist advice (Published 4 November 2020; checked 15 August 2026) — https://www.nice.org.uk/guidance/ng184/chapter/Recommendations NHS Scotland Right Decisions: Hand injuries — Hand bites (December 2024; checked 15 August 2026) — https://www.rightdecisions.scot.nhs.uk/media/jujp5l25/hand-injuries-dec-24.pdf