Narcolepsy presenting as refractory epilepsy

Abstract

A 12-year-old boy presented with episodes of sudden fall, several times a day for last 6 months. These episodes of 5-10 seconds were associated with upward rolling of eyes. CT scan cranium and EEG were normal. A local practitioner made diagnosis of epilepsy and the child was put on phenytoin and sodium valproate. Even after 4 months of treatment, there was no reduction in symptoms and patient was referred to us. Detailed history revealed that child had a history of excessive daytime sleepiness for past one year. There was no history of sleep paralysis or hallucinations. Preceding emotions did not trigger these episodes of collapse. These events were not associated with change in posture, prolonged standing. There was no history of drug intake, palpitation, headache or anxiety. Anti-epileptic drugs were withdrawn and clinical diagnosis of narcolepsy with cataplexy was made. Overnight polysomnography was done and it was followed by multiple sleep latency test (MSLT) on next morning. Polysomnography was normal, but MSLT revealed sleep latency time of 0.7 minute and 2 episodes rapid eye movement (REM) sleep out of 4 recorded naps of 20 minute each. These findings of MSLT were consistent with narcolepsy. His parents were educated about the importance of scheduled naps, regular sleepwake schedule and overall good sleep hygiene. Modafinil acetamide 100 mg two times a day was given for excessive daytime sleepiness. Clomipramine, 25 mg at bedtime, was given for cataplexy. Clomipramine was withdrawn on subsequent visits. Presently the child is on modafinil alone for past 6 months and all symptoms have subsided. Narcolepsy is often recognised by excessive daytime sleepiness and associated pathological manifestation of REM sleep like cataplexy, sleep paralysis and hypnagogic hallucinations. Automatic behaviours and disrupted nighttime sleep also occur commonly. Out of all REM sleep manifestations, cataplexy is unique to narcolepsy. It is an abrupt and reversible decrease or loss of muscle tone, most frequently elicited by emotion such as laughter, anger or surprise. Any preceding or anticipation of strong