skip to main content

Periodic Alternating Nystagmus – Baclofen — SCE Neurology MCQ

Instant feedback + full explanation. One question, done properly.

HardNeuro-ophthalmologyPeriodic Alternating Nystagmus – BaclofenSCE Neurology

A 55-year-old man presents with a progressive right-beating horizontal nystagmus that changes direction — becoming left-beating after approximately 2 minutes. This cycle repeats every 4 minutes (periodic alternating nystagmus). MRI brain shows a lesion at the craniocervical junction. What is the first-line treatment for periodic alternating nystagmus?

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

Reveal the answer and explanation

Correct answer: B — Baclofen

Periodic alternating nystagmus (PAN) is a form of acquired jerk nystagmus that changes direction cyclically (typically every 2–4 minutes). It is usually caused by lesions at the craniocervical junction (Chiari malformation, MS, stroke) affecting the velocity storage mechanism in the vestibular nuclei and cerebellum. Baclofen (a GABA-B agonist) is the first-line treatment and is often dramatically effective. A: Gabapentin is for pendular nystagmus. C: Memantine is for pendular nystagmus. D: Carbamazepine is for trigeminal neuralgia. E: Baclofen is effective.

Reference: ABN Neuro-ophthalmology Guidelines; Halmagyi et al. PAN Treatment