Hypersomnia due to a medical condition (Q40763)

Hypersomnia due to a medical condition is characterised by excessive nocturnal sleep, daytime sleepiness, or excessive napping of at least several months duration that is attributable to a coexisting medical or neurological disorder (e.g. head trauma, Parkinson disease, certain genetic conditions, metabolic, neurologic or endocrine disorders) and is sufficiently severe to require an independent focus of clinical attention. Hypersomnia due to a medical condition is only diagnosed if the hypersomnia is a direct physiological consequence of the medical condition. Residual sleepiness in patients with adequately-treated obstructive sleep apnoea is classified here under the assumption that it is due to central nervous system damage from recurrent hypoxemia. Note: A definitive diagnosis requires use of polysomnography and multiple sleep latency test (MSLT) to rule out other hypersomnolence disorders or other sleep disorders (e.g. obstructive sleep apnea) which might better explain the sleepiness.