Non-24-hour sleep-wake disorder (N24SWD) is a circadian rhythm disorder that leads to the inability to consistently sync the sleep wake (SW) pattern to the 24 hour day night cycle. Patients with N24SWD have progressively delayed SW patterns that occur in a cyclic fashion leading to significant interruptions to daily life. N24SWD is most commonly observed in non-sighted individuals impacting an estimated 50% of that population. It is exceedingly rare in patients with sight, with the first published case in 1971. Furthermore, this is even rarer, if ever, previously described in the pediatric population.
A 12-year-old male was referred for excessive daytime sleepiness and abnormal sleeping patterns. His bedtime is progressively more delayed each day. During periods of unrestricted sleep, sleep onset delays 2-3 hours each night, with a sleep latency of about 30 minutes and 8-10 hours of sleep duration. Return to a normal bedtime of 9:00pm occurs every 7-10 days. There was no other significant sleep history. He denies sleep paralysis, hypnogogic and hypnopompic hallucinations, and snoring. Melatonin had inconsistent success and adverse effects. The patient’s neurological examination was unremarkable.
Actigraphy confirmed the diagnosis of N24SWD demonstrating cycling of SW when allowed a free sleep schedule. Brain MRI without contrast was unremarkable. The patient was initiated on tasimelteon which led to significant improvements in his ability to maintain a consistent bedtime.
This case demonstrates that not only can N24SWD occur in sighted individuals, but it can certainly be present in the sighted pediatric population. If not identified, it can lead to long term effects on a child’s life, affecting their development and education. This case also demonstrated the benefits of selective melatonin agonists in the treatment of this condition.