1071 Secondary Hypersomnia in a patient with myotonic dystrophy

Introduction Myotonic dystrophy type I (DM1) is the most common adult-onset form of muscular dystrophy with autosomal dominant inheritance and incomplete penetrance. EDS is the most frequent non-muscular symptom and patients may present with EDS for years before DM1 is diagnosed. We are presenting an 18-year-old Caucasian female with myotonic dystrophy and progressive daytime sleepiness. Report of Case 18 y/o female with medical history of myotonic dystrophy, scoliosis s/p spinal fusion, pectus excavatum, restrictive lung disease, exercise induced asthma, chronic abdominal pain was following in the myotonic dystrophy clinic for 4 years. She has a long and complicated medical history and currently on Baclofen, Carbamazepine, Clonazepam, Duloxetine, Cyproheptadine, Diazepam, Gabapentin and Prednisone. She had complaints of decreased exercise tolerance, daytime fatigue, snoring and excessive nocturnal sleep (11–12 hours) but no significant daytime sleepiness. She had three sleep studies done 2 years apart showing normal sleep with absence of significant sleep disordered breathing. In the past several months she reported more daytime sleepiness and occasional sleep in school. Multiple sleep latency test done after the third sleep study shows mean sleep latency of 3 minutes with no sleep onset REM episodes. She has recently been started on clinical trial of Modafinil. Conclusion In patients with DM1, sleepiness mainly occurs in monotonous situations in contrast to narcolepsy. Sleepiness is mostly unrelated to the duration and the quality of the night time sleep. Sleep phenotype is closer to that of idiopathic hypersomnia with long sleep time (ICSD-2), along with increased sleep fragmentation related to respiratory events, nocturnal agitation, reduced motility and pain. Increased SWS/REM and decreased N2 with impaired delta power dissipation have been reported. Different phenotypes mimic idiopathic hypersomnia, narcolepsy without cataplexy, sleep apnea syndrome, and periodic leg movement disorder, however there is no clear data on how and when to evaluate sleep complaints and clarify the indications of different tools and the frequency of repetition to identify and manage these problems.