Restless Legs Syndrome (RLS) May Be Associated With Small Intestinal Bacterial Overgrowth and Improve With Antibiotic Treatment
RLS etiology remains unclear, although alterations in dopamine and iron homeostasis may play a role. Small intestinal bacterial overgrowth (SIBO) is a common condition in which excessive levels of bacteria are present in the small intestine. A link between SIBO and RLS has been recently recognized. Dopamine agonists are standard therapy for RLS but may cause adverse events; thus, new therapies are needed.
This study examined the prevalence of SIBO in patients with idiopathic RLS and the effect of rifaximin, a nonsystemic antibiotic, on RLS symptoms.
Patients had RLS if they met all 4 international RLS criteria. Patients were screened for SIBO using a lactulose breath test (LBT). Patients with RLS and abnormal LBT results received rifaximin 400 mg 3 times a day for 10 days followed by 400 mg/d for 20 days. LBT was repeated on day 12. On days 12, 20, and 30, general global assessment of RLS and gastrointestinal (GI) symptoms was conducted. The international RLS (IRLS) symptom scale (range, 0-40) was used to determine RLS severity.
Of 21 RLS patients screened, 15 (71%) had an abnormal LBT result. One patient with Helicobacter pylori infection was excluded. The 14 remaining patients reported having RLS symptoms for a mean of 6.8 ± 7.5 years. Mean baseline IRLS symptom severity score was 23.1 ± 6.2. Post-treatment, 9 patients identified themselves as global RLS clinical responders (markedly, moderately, or slightly improved) and 5 were nonresponders (unchanged or slightly, moderately, or markedly worse) Mean IRLS severity scores for all patients were 23.1, 17.9, 16.2, and 14.8 at baseline, day 12, day 20, and day 30, respectively. At the same time points, mean IRLS scores for responders were 22.9, 14.6, 12.8, and 12.2, respectively. Percent change from baseline in IRLS severity score was 40.2% ± 0.44% in all patients (range, -55.0% to 100.0%) and 65.6% ± 25.2% in responders (range, 31.0% to 100.0%). Two nonresponders who received additional combination antibiotics had a significant reduction in RLS symptoms.
This pilot study supports the hypothesis that SIBO may contribute to RLS symptoms and suggests that antibiotics (e.g., rifaximin) may alleviate RLS symptoms.
3rd International Congress on Sleep Medicine of the World Association of Sleep Medicine (Sao Paulo, Brazil)