Narcolepsy and hypersomnolence — formative SAQs

SAQ 1 — The child who collapses when he laughs (10 marks, 15 minutes)

A ten-year-old boy has developed irresistible daytime sleepiness over three months, falling asleep in class and at meals despite a normal night-time sleep schedule. His parents report that when he laughs hard his knees buckle and his head drops for a second or two, and he stays fully aware. He has also gained weight rapidly over the same period. ^[1]

a) What is the most likely diagnosis, and which single feature of the history is nearly specific for it? (3 marks) ^{[2] [9]}

b) What investigations would confirm the diagnosis, and what findings would you expect? (4 marks) ^{[3] [10]}

c) Outline your management, including the non-drug foundation and the drugs you would use for sleepiness and for the emotion-triggered symptom. (3 marks) ^{[12] [13]}