Restless legs syndrome in patients with systemic sclerosis. Prevalence and possible causes.

This study aims to assess the prevalence and possible causes of restless legs syndrome (RLS) in patients with systemic sclerosis (SSc). The prevalence of RLS was assessed in 27 patients with SSc and 60 healthy controls. We evaluated the impact of age, disease duration, disease form, antibodies, and metoclopramide on the development of RLS in SSc patients. In order to reveal peripheral neuropathy or iron deficiency as possible causes of the syndrome, patients with RLS underwent electromyoneurography (EMNG) and ferritin level testing. RLS was diagnosed in 40.7% of SSc patients (11 out of 27), compared to 4.9% of healthy controls (p< 0.001). Eight out of 18 patients (44.4%) with diffuse SSc and 3 out of 9 patients (33.3%) with limited SSc exhibited RLS (p = 0.28). Mean age and mean disease duration did not differ significantly between patients with or without RLS. RLS was observed in 47.1% of patients with anticentromere antibodies and 30% of patients with anti-topoisomerase I antibodies (p = 0.22). RLS was diagnosed more frequently (p = 0.02) in patients taking metoclopramide (75%) than in patients who were not being treated with this drug (26.3%). EMNG revealed sensitive polyneuropathy in four, and lumbosacral radiculopathy in two out of 11 patients with RLS. Two patients with SSc and RLS had low levels of ferritin. Three patients had normal EMNG findings and ferritin levels. In conclusion, RLS is a common disorder in patients with SSc. Possible causes include sensitive polyneuropathy, lumbosacral radiculopathy, and iron deficiency. A strong relationship was observed between RLS and metoclopramide, which is sometimes used to treat SSc-related gastrointestinal motility disturbances.