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Infected cat bite in pregnancy with immediate penicillin hypersensitivity — MSRA MCQ

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HardInfectious DiseasesInfected cat bite in pregnancy with immediate penicillin hypersensitivityMSRA

A 34-year-old woman who is 19 weeks pregnant presents 20 hours after being bitten on the right index finger by her pet cat. Two puncture wounds broke the skin and bled. Despite thorough irrigation immediately after the injury, she now has increasing local pain, warmth, swelling and erythema around the wounds. She is afebrile, has no lymphangitis, and is systemically well. Active and passive finger movement are full and painless; neurovascular examination is normal. Three years ago, she developed urticaria, wheeze and hypotension within 30 minutes of taking co-amoxiclav, requiring emergency treatment. She can take oral medication. What is the most appropriate antimicrobial management now?

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Correct answer: B — Seek same-day specialist advice on an alternative oral antibiotic regimen

This is an infected cat bite rather than an uninfected exposure requiring prophylaxis: progressive pain, warmth, swelling and erythema after puncture wounds indicate established local infection. Oral treatment is appropriate because she is systemically well, can take oral medication and has no features suggesting tendon, joint, neurovascular or deep-structure involvement that would mandate hospital referral. Co-amoxiclav is the usual first-line oral treatment for infected cat bites, but her immediate reaction was consistent with anaphylaxis, so it should not be prescribed. NICE recommends doxycycline plus metronidazole as the alternative first-choice oral regimen for non-pregnant adults when co-amoxiclav is unsuitable. However, for a pregnant patient with penicillin allergy or where co-amoxiclav is unsuitable, NICE specifically advises seeking specialist advice, to select an effective regimen with appropriate activity against likely bite pathogens, including Pasteurella species. Clarithromycin plus metronidazole may appear to provide broad cover but is not the NICE-recommended empiric alternative in this setting. Intravenous therapy and hospital assessment would become appropriate if she were systemically unwell, unable to take oral treatment, had severe infection, or had evidence of penetrating injury involving a tendon, joint, bone, nerve or vessel.

Reference: NICE NG184: Human and animal bites: antimicrobial prescribing — Recommendations (04 November 2020) — https://www.nice.org.uk/guidance/ng184/chapter/Recommendations NICE NG184: Human and animal bites: antimicrobial prescribing — Rationale and impact (04 November 2020) — https://www.nice.org.uk/guidance/NG184/chapter/rationale-and-impact