Prevalence of Restless Leg Syndrome in Skin Biopsy Proven Small Fiber Neuropathy (5243)

Objective: Associations between peripheral neuropathy and restless legs syndrome (RLS) are described but exact correlation remains inconsistent. Specifically, prevalence of RLS in histologically proven small fiber neuropathy (SFN) or correlation of RLS severity to SFN severity remains unknown. This study aims to address this void to improve quality of life (QOL) by identifying treatable comorbidity of RLS in SFN. Background: Dopaminergic dysfunction in RLS can lead to loss of supraspinal inhibition and enhanced excitability of propriospinal mechanisms. Additionally, abnormal sensory inputs in SFN worsen this inhibition secondary to altered dorsal horn physiology contributing to RLS. Design/Methods: A prospective study to assess prevalence of RLS in SFN is underway. We present preliminary results. 13 patients diagnosed with SFN showing reduced intradermal nerve fiber (IDNF) layer density were screened for RLS using standardized questionnaire based on the International RLS study group diagnostic criteria (IRLSRS). All patients who answered yes to three or four questions were considered screen-positive and further analysis regarding RLS severity was performed. We plan to study correlation of SFN severity based upon IDNF density to IRLSRS severity. Results: Out of 13 patients with SFN, 2 patients did not address all 4 questions. 9 patients endorsed 3 or 4 symptoms, and 2 patients endorsed 1 or 2 symptoms displaying RLS in 81.82% SFN. All 13 (100%) admitted unpleasant sensations combined with an urge to move legs and 10 (90.91%) noticed symptoms at rest or periods of inactivity. 6 (54.55%) admitted such sensations improved with movements and that such feelings were worse at night or evenings. The mean severity score was 26.33 and median 29 suggesting severe RLS per IRLSRS. Conclusions: This study demonstrates that SFN is associated with RLS with significant impact on QOL. Exploration of correlation between severity of SFN based on IDNF density to severity of RLS will enhance understanding of these comorbidities. Disclosure: Dr. Desai has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Alexion, Stealth BioTheraputics, CSL Behring. Dr. Desai has received research support from Not personally or for Investigator Initiative Studies. Engaged as PI and SubPI in commercially sponsored research trials. Dr. Brooks has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Mitsubishi Tanabe Pharma USA, Biohaven, Cytokinetics, ITF Pharma, Biogen. Dr. Brooks has received personal compensation in an editorial capacity for American Journal of Managed Care. Dr. Brooks has received research support from Medicinova, Neuraltus, Cytokinetics,Santhera, Biogen, ITF Pharma, Acceleron, Center for Disease Control, Orion, Biohaven.