[Note: SIBO is a condition where abnormally large numbers of bacteria are present in the small intestine where nutrient absorption takes place, and these bacteria are the types typically found downstream in the colon.]
Background: Restless legs syndrome (RLS) is linked to gastrointestinal disorders. The prevalence of irritable bowel syndrome (IBS) and small intestinal bacterial overgrowth (SIBO) in RLS patients was determined.
Methods: RLS subjects were recruited from unbiased ads that did not mention gastrointestinal symptoms. RLS diagnosis was confirmed by a neurologist and utilized the International RLS Study Group criteria.
General population controls (GPC) were spouses of gastrointestinal clinic patients and were excluded for RLS.
Completely healthy controls (CHC) were excluded for RLS and gastrointestinal symptoms.
IBS was diagnosed by Rome II criteria. SIBO was diagnosed by the lactulose breath test (LBT).
Results: There were 32 RLS subjects (23F/9M; 57 yo), 25 GPC (13F/12M; 58 yo) and 30 CHC (19F/11M; 44 yo). Twenty-nine had RLS unassociated with other GI diseases, one had celiac disease, and two had gastric resections.
• IBS was diagnosed in 28% of RLS subjects compared to 4% of general population controls (p=0.0317).
• SIBO was diagnosed in 69% of RLS subjects compared to 28% of general population controls (p=0.0033) and 10% of completely healthy controls. Using a false positive rate of 10%, 59% of positive lactulose breath test results are associated with RLS.
Conclusions: IBS and SIBO are common in RLS. Three hypotheses developed are:
a. RLS patients are selectively immunocompromised or genetically predisposed and thus more subject to SIBO;
b. Small intestinal bacterial overgrowth leads to autoimmune changes, and subsequent auto-antibodies attack brain and/or peripheral nerves, and
c. Small intestinal bacterial overgrowth inflammation leads to increased hepcidin and CNS iron deficiency which, in turn, leads to RLS.
These hypotheses bear further investigation.
Source: Sleep Medicine, May 12, 2011. PMID: 21570907, by Weinstock LB, Walters AS. Department of Internal Medicine, Washington University School of Medicine and Specialists in Gastroenterology, LLC, St. Louis, Missouri; Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [Email: firstname.lastname@example.org]