A 58-year-old hypertensive man presents with sudden vertigo, hoarseness, and difficulty swallowing. Examination shows loss of pain and temperature sensation on the right face and left trunk and limbs, right Horner syndrome, ataxia of the right limbs, and palatal paralysis with diminished gag reflex on the right. Which artery is most likely occluded?

• A Anterior inferior cerebellar artery
• B Posterior inferior cerebellar artery ✓
• C Superior cerebellar artery
• D Posterior cerebral artery

Explanation

The combination of nucleus ambiguus involvement (hoarseness, dysphagia, absent gag), ipsilateral Horner syndrome, ipsilateral facial and contralateral body pain-temperature loss, and ipsilateral cerebellar ataxia defines lateral medullary (Wallenberg) syndrome, classically due to posterior inferior cerebellar artery or vertebral artery occlusion. The anterior inferior cerebellar artery causes lateral pontine syndrome with ipsilateral facial weakness and deafness, which this patient lacks.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.