Obstructive sleep apnoea with co existent Kleine-Levine syndrome in a middle-aged man.

Hypersomnia is a symptom which is pathognomonic of patients with Kleine-Levin syndrome (KLS), but the cause of this finding remains undefined. Given the pervasive association between obstructive sleep apnoea (OSA) and excessive daytime sleepiness, there exists the possibility that OSA might contribute to the sleepiness exhibited by these patients. Here we report a middle age man who had excessive daytime sleepiness and diagnosed as OSA after polysomnography. Prescribing of continuous positive airway pressure (CPAP) lead to unmasking of episodes of increased sleepiness and other behavioural features of KLS.