Atypical Kleine--Levin syndrome: can insomnia and anorexia be features too?

Kleine-Levin syndrome is an uncommon disorder with recurrent episodes of hypersomnia, clearly associated with behavioral abnormalities like binge eating, hypersexuality and abnormal behavior. Many patients may not necessarily fulfill minimum criteria described for diagnosis. We aim to report such patients with atypical presentation resembling the Kleine-Levin syndrome.

We evaluated all patients at our clinic who had episodic disturbance in sleep and/or appetite lasting a few days to weeks, not necessarily fulfilling the International Classification of Sleep Disorders (ICSD) criteria for a diagnosis of Kleine-Levin syndrome, over 4 years. All clinical details, especially regarding sleep, appetite and behaviour during episodes, about prior and co-existing illnesses were noted. All patients were investigated with brain magnetic resonance imaging (MRI), electroencephalogram (EEG) and some with polysomnography.

Eighteen patients (5 females, 13 males) ranging in age from 12 to 55 years (median 18 years) were included in the study. The median duration of symptoms was 1.5 years, and the median number of episodes in each patient was six. The range of episode length was 18-300 h with a mean of 91.2h. Fourteen patients had a history of hypersomnia, 3 had only insomnia and 3 had both during their episodes, while 5 patients reported hyperphagia, 11 reduced appetite and 2 no change in appetite. Ictal EEG revealed evidence of sleep, while polysomnography showed reduced rapid eye movement (REM) latency and normal sleep architecture during the episode. MRI was normal in all patients, except one who showed non-specific abnormalities. All patients showed improvement with carbamazepine.

There are many patients with episodic alteration in sleep, appetite and behaviour with a course and treatment response similar to the classical Kleine-Levin syndrome, who otherwise do not fit the classical description for diagnosis of this condition.