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Narcolepsy type 1 — SCE Neurology MCQ

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HardSleep DisordersNarcolepsy type 1SCE Neurology

A 24-year-old man has irresistible daytime sleep attacks, vivid hallucinations at sleep onset and episodes of knee buckling when laughing. Overnight polysomnography excludes sleep apnoea. Multiple sleep latency testing shows mean latency 3 minutes with two sleep-onset REM periods. What is the most likely diagnosis?

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Correct answer: A — Narcolepsy type 1

Narcolepsy type 1 is the best answer. Excessive daytime sleepiness with cataplexy and sleep-onset REM periods after excluding sleep deprivation/apnoea indicates narcolepsy type 1. Idiopathic hypersomnia lacks cataplexy and SOREMP pattern; OSA was excluded; temporal epilepsy has stereotyped seizures; Kleine-Levin syndrome causes episodic hypersomnia with behavioural changes. Clinical pearl: Cataplexy is emotion-triggered weakness with preserved awareness.

Reference: ICSD-3 sleep disorder criteria; NICE CKS narcolepsy