Clostridioides difficile infection — MCCQE Part 1 MCQ

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ModerateDiarrheaClostridioides difficile infectionMCCQE Part 1

A 76-year-old woman develops watery diarrhoea 1 week after clindamycin, has leukocytosis and positive stool toxin testing. Which of the following is the most appropriate next step?

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Correct answer: E — Treat with oral vancomycin or fidaxomicin and stop unnecessary inciting antibiotics

Treat with oral vancomycin or fidaxomicin and stop unnecessary inciting antibiotics is the single best answer because the age, timing, examination findings and investigations in the vignette fit Clostridioides difficile infection better than the alternatives. The most tempting distractor is less appropriate because it either treats a neighbouring presentation, delays a time-critical intervention, or ignores a key discriminator in the stem. The remaining options are suboptimal because they would miss the diagnosis, use an investigation or treatment in the wrong sequence, or fail to address safety and follow-up. Canadian practice should be anchored to AMMI Canada C. difficile guidance, with attention to acuity, safety-netting and local provincial pathways.

Reference: AMMI Canada C. difficile guidance