1223 REM-related Leg Cramps

Abstract Introduction Nocturnal leg cramps are common in the general population and is reported in 30% of adults. It is described under sleep related movement disorders in the International Classification of Sleep Disorders. It is a painful sensation in the legs that occurs during sleep or out of sleep but is not necessarily associated with a particular stage of sleep, relieved by stretching. We present a case of nocturnal leg cramps occurring during REM sleep. Report of case(s) Patient is a 53-year-old female reporting a history of waking from sleep with leg cramps. She underwent a CPAP titration study at our facility for a previously documented obstructive sleep apnea (AHI of 28, REM AHI of 74.1). On video, she was seen to wake abruptly out of each of the three REM sleep episodes, sitting and rubbing her calves, and reporting to the technician that she was having leg cramps. She would then get up and walk around to relieve the cramps but was able to return to sleep. Each episode lasted 3-5 minutes and was only relieved with movements or massage. No leg cramps were reported from non-REM sleep during this study. She denied symptoms of restless legs syndrome. Her periodic limb movements of sleep indices during her diagnostic and CPAP polysomnograms were 2.0 and 5.1 respectively and occurred during non-REM sleep. Medical history includes asthma and COPD (oxygen supplementation as needed), heart disease, prior polysubstance use disorder, and treated infective endocarditis in 2011. Conclusion Our case characterizes nocturnal leg cramps that occurred at a particular sleep stage, in this case strictly during REM sleep. Nocturnal leg cramps have been reported in the literature in association with various medical comorbidities including vascular disease and OSA. Further, it has been reported that CPAP therapy for OSA results in near or total elimination of leg cramp burden. It is unclear what is the mechanism of REM-related leg cramps, but it could be the REM OSA. To our knowledge, this is the first documented case of REM-related nocturnal leg cramps. We hope to add to the present literature on the mechanism of this disorder. Support (if any)