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Vertebral Dissection – Lateral Medullary Syndrome — SCE Neurology MCQ

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ModerateCerebrovascular DiseaseVertebral Dissection – Lateral Medullary SyndromeSCE Neurology

A 55-year-old man presents with sudden onset of ipsilateral facial pain, ipsilateral Horner syndrome, and contralateral hemiparesis. He also has ipsilateral lower cranial nerve palsies (hoarseness, dysphagia) and contralateral hemisensory loss. MRA shows a right vertebral artery dissection extending to the intracranial segment. Which artery territory is most likely occluded?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Posterior inferior cerebellar artery

Explanation lettering: C = shown as A · A = shown as C · E = shown as D · D = shown as E

Vertebral artery dissection can occlude the PICA (which arises from the vertebral artery), causing a lateral medullary syndrome (Wallenberg syndrome): ipsilateral facial pain (trigeminal nucleus), ipsilateral Horner syndrome (descending sympathetics), ipsilateral palatal/vocal cord/pharyngeal weakness (nucleus ambiguus — CN IX, X), contralateral body pain/temperature loss (spinothalamic tract), and ipsilateral cerebellar ataxia (inferior cerebellar peduncle). A/B: These are anterior circulation vessels. D: Anterior choroidal artery supplies the posterior limb of the internal capsule. E: SCA supplies the superior cerebellum.

Reference: RCP National Clinical Guideline for Stroke (2023); Clinical Neuroanatomy