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Guillain-Barre syndrome — USMLE Step 2 CK MCQ

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HardInternal MedicineGuillain-Barre syndromeUSMLE Step 2 CK

A 50-year-old Hispanic man comes to the clinic because of neurologic symptoms. History and focused examination are notable for ascending weakness, areflexia, and albuminocytologic dissociation after infection. Temperature is 98.6°F (37.0°C), blood pressure is 126/78 mmHg, pulse is 84/min, respirations are 16/min, and oxygen saturation is 98% on room air. Physical examination confirms the key finding and shows no unrelated abnormality that would better explain the presentation. Focused laboratory studies and initial testing support the clinical pattern described in the stem. Which of the following is the most likely cause of this patient's condition?

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Correct answer: E — Postinfectious immune-mediated demyelination of peripheral nerves

The vignette describes Guillain-Barre syndrome, supported by ascending weakness, areflexia, and albuminocytologic dissociation after infection. Postinfectious immune-mediated demyelination of peripheral nerves is the single best answer because it matches the diagnostic or management priority in this clinical setting. The other choices are plausible alternatives in related presentations, but they do not best fit the timing, findings, and guideline-directed approach described here.

Reference: https://www.ncbi.nlm.nih.gov/books/#stage-9-order-15