Video-Clinical CornersNear resolution of sleep related rhythmic movement disorder after CPAP for OSA
Introduction
Sleep related rhythmic movement disorder (RMD) is characterized by repetitive, stereotyped, and rhythmic motor behaviors that involve large muscle groups and occur predominantly during drowsiness and light sleep, though they can appear in any sleep stage [1]. Diagnosis is often but not always straightforward, especially when RMD involves movement patterns other than the most classic body rocking or head banging, or when the patient presents initially in adulthood rather than childhood. We describe an adult diagnosed with RMD only after being treated for restless legs syndrome (RLS) and referred for evaluation of obstructive sleep apnea. Furthermore, treatment of this patient’s obstructive sleep apnea dramatically reduced the RMD.
Section snippets
Case description
A 38-year-old man was referred to our sleep laboratory because of a history of loud snoring and witnessed apneic episodes. The patient denied any history of daytime sleepiness, and his Epworth Sleepiness Scale score was only 2 (on a scale of 0 to 24) [2]. He did have a history of repetitive bilateral leg rolling movements noted nightly by his wife since they were married 17 years prior. The patient typically had these movements for extended periods before falling asleep, but also occasionally
Video and image analysis
A diagnostic video-polysomnogram (V-PSG) revealed severe obstructive sleep apnea with an apnea-hypopnea index of 87 events per hour of sleep and a minimum oxygen saturation of 73% [3]. His periodic limb movement index was 0.
The V-PSG also showed frequent rhythmic movements of the lower extremities and pelvis (see online video). These movements occurred at a rate of about 1.5 Hz, and involved side-to-side rolling of the legs in unison, sometimes more prominently on the left, with movement often
Discussion
Our patient’s presentation with restless sleep and abnormal leg movements led to his initial diagnosis and treatment for RLS, despite the lack of any urge to move the legs or unpleasant leg sensations [1], any response to a dopamine agonist, or any clinical consequences from his involuntary leg movements [4]. This patient’s polysomnogram later showed no evidence of periodic limb movements (PLMs), normally observed in 80–90% of patients with RLS [1]. Other diagnostic considerations also could
Disclosure
The authors report no conflicts of interest.
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