Abstract Introduction Restless sleep disorder (RSD) is an increasingly recognized sleep-related movement disorder causing significant daytime impairment. RSD has an estimated prevalence of 7.7% in pediatric patients seen in sleep medicine clinics. Similar to other sleep-related movement disorders, RSD has been associated with low iron stores. However, RSD differs from other sleep-related movement disorders as it is defined by the presence of large muscle movements. Given the relatively recent formal description of RSD, overall reported cases remain low. We present a case of RSD and low ferritin levels with response to oral iron supplementation. Report of case(s) A 15-year-old female with no pertinent past medical history presented with concerns of insomnia and being a light sleeper. Her parents noted that she moved a lot while sleeping, often kicking both legs or tossing and turning. The Exact onset was unclear, though symptoms have been present for many years. Polysomnography was performed showing the presence of frequent large muscle movements. The large muscle movements were present in N2, N3, and R sleep, though the majority of events occurred in N2 sleep. The large muscle movement index was 5.34/hour, meeting the proposed criteria for RSD. She also had periodic limb movements of sleep (PLMS) with an index of 10.8/hour; however, the PLMS were not associated with arousals and did not fragment her sleep. Iron studies were checked shortly before her initial presentation to the sleep clinic. Her ferritin level was low at 7 ng/mL. She was subsequently started on daily oral iron supplementation with Iron-Vitamin C 65-125mg tablets. After one month of oral iron supplementation, symptoms have started to improve, with parents noting less movement in sleep and sleep being more restful. Conclusion RSD is an important diagnostic consideration when evaluating pediatric patients with concerns of maintenance insomnia or frequent sleep-related movements. This report provides an example of RSD in the setting of low ferritin levels. Furthermore, iron repletion is essential in the management of RSD with comorbid low iron stores. Proper iron supplementation in these patients can alleviate symptoms and improve overall sleep quality. Support (if any)
Dunlow et al. (Fri,) studied this question.