Narcolepsy with Obstructive Sleep Apnea in a 4-Year-Old Korean Girl: A Case Report
On May 2, 2012, a 4-yr-old girl was found to have exhibited severe snoring, restless sleep, and increasing daytime sleepiness over the last 3 months. Her mother reported that she snored terribly all over the night and that several pauses in her breathing were observed at night. The patient had no difficulty falling asleep at night and she had relatively regular sleep schedule from 21:00 to 07:00, but she usually awoke from her sleep 4 to 5 times during nighttime. In the morning, she hardly felt refreshed after a sleep and looked very tired even after getting out of bed. The child tended to be good at preschool learning and activities and she rarely has taken a nap in the kindergarten since September, 2011. However, she fell asleep in the middle of a class or took a nap for more than two hours, and even after coming back home, she complained of sleepiness and got another sleep for two hours or so in the afternoon in the last several months.\nHer mother denied any history of cataplexy and it was difficult to verify the presence of hypnogogic or hypnopompic hallucinations or sleep paralysis because she was too young to understand and describe those symptoms. Neither her birth history nor past medical history was remarkable. On physical examination, her blood pressure was 115/75 mm Hg, her pulse rate was 65 beats per min, and her respiratory rate was 23. She was 112 cm in height and 19 kg in weight, and her BMI was 17.2 (40 percentile for her age). Her nares and nasal septum were within normal limits. She had kissing tonsils and edematous uvula. OSA was suspected, and she underwent overnight polysomnography (PSG) from 21:00 to 07:30, which demonstrated an apnea/hypopnea index of 5.2 and the minimum oxygen saturation of 88%. The following day, multiple sleep latency tests (MSLT) were performed at two hours interval from 09:00, the study showed a mean sleep latency of 3.5 min and one sleeponset REM period (SOREMP) (). On this basis, the patient was diagnosed with OSA and was referred to otolaryngology for surgical evaluation.\nAfter tonsillectomy and adenoidectomy (T&A), her sleep became much calmer, snoring was eliminated, and daytime somnolence decreased. At one-month follow-up, her mother was satisfied with the outcome of the surgery but worried about persistent hypersomnia even though enough sleep at night. Since the child still took a nap for more than three hours in the kindergarten and at home, a follow-up sleep test was conducted. She underwent another overnight PSG followed by MSLT, which showed no sleep apnea but the mean sleep latency of 8 min and two SOREMPs (). Diagnosis of OSA to be effectively treated by T&A and narcolepsy without cataplexy was confirmed. She started taking modafinil 100 mg per day but she was still sleepy during daytime and complained of sleep disturbance at night such as sleep onset delay and night wakings. The medication was changed into methylphenidate 10 mg per day, and the child was allowed to have a short (less than 30-min) nap around 13:00. After that, daytime somnolence and sleep disturbance were much improved and she has relatively good quality of life with stable daily activities.