Narcolepsy, metabolic syndrome and obstructive sleep apnea syndrome as the causes of hypersomnia in children. Report of three cases.

Hypersomnia is a significant problem in about 5% of the general population. We discussed clinical aspects in 3 patients with hypersomnia diagnosed in our sleep laboratory. All of the patients, both obese and non-obese, presented abnormal oral glucose tolerance test (OGTT) and plasma insulin level. (1) A 17-year-old girl (BMI = 20.3) with a two-year history of daytime sleep attacks (e.g. on the bus, in a classroom, while reading or eating), followed by refreshed feeling. The first symptoms appeared 2 years after spine injury (L2-L3). Total sleep time was > 98 perc. The diagnosis of narcolepsy was confirmed by sleep-onset REM periods in 3 of 4 daytime naps (positive Multiple Sleep Latency Tests) and HLA-DQB1 (alleles *0201, *0602). (2) A 16-year-old girl (BMI = 32.4) with a history of increased sleepiness (Epworth Sleepiness Scale score = 13), not refreshing naps, along with BMI increase, since the age of 13. The metabolic syndrome was diagnosed based on the presence of obesity, hypercholesterolemia (CH = 240 mg/dl, HDL-CH = 49 mg/dl) and insulin resistance (HOMA index = 6.75, hyperinsulinemia--367 microU/mL at 30' after OGTT). (3) A 6-year-old boy (BMI = 16.0) with a 10-month history of daytime sleep attacks and postprandial sleepiness; nocturnal enuresis, high simple carbohydrate diet, low plasma insulin level after OGTT. Diagnosis of food-related hypersomnia and obstructive sleep apnea was confirmed when the boy recovered after his nutrition habits had been changed, which resulted in decreased respiratory disturbance index (RDI) from 17.7/h in October 2005 to 2.9/h in October 2006. Within that time his parents did not observe any episodes of daytime sleepiness, irritability or nocturnal enuresis.