Researchers investigating a link between restless legs syndrome (RLS) and Crohn’s disease (CD) uncovered results that demonstrate RLS occurs frequently in people with CD and appears to be a possible extraintestinal manifestation of CD. This research appeared in the February 2010 issue of Inflammatory Bowel Disease.
CD is an ongoing disorder that causes inflammation of the digestive tract, also referred to as the gastrointestinal (GI) tract. CD can affect any area of the GI tract, from the mouth to the anus, but it most commonly affects the lower part of the small intestine, called the ileum.
CD has a variety of possible extraintestinal manifestations: arthritis, skin problems, kidney stones, gallstones, and liver diseases. This study is the first to show central nervous system (CNS) manifestations of CD.
RLS is a condition in which a person experiences extreme leg discomfort while sitting or lying down. RLS may be primary or secondary to a number of disorders. Secondary RLS occurs in a variety of patient populations, including pregnant women and people with end-stage renal disease, iron-deficiency anemia, rheumatoid arthritis, diabetes, Parkinson’s disease, or fibromyalgia.
Because both CD and RLS are associated with iron deficiency, GI tract inflammation, and bacterial overgrowth, researchers designed the study to investigate the potential link between these two disorders.
“Overall, RLS was found to be a common comorbid condition in patients with CD,” stated Leonard B. Weinstock, M.D., Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, and colleagues. “The incidence of RLS in patients with CD reported in this study was greater than the incidence of many of the known extraintestinal manifestations of CD.”
A total of 272 patients with CD participated in the study, and researchers found a 43 percent incidence rate and 30 percent prevalence rate of RLS in patients with CD, compared with a 9 percent prevalence rate in the control group. RLS symptoms occurred during or after the onset of CD symptoms in the majority of patients, suggesting a link between CD and RLS.
Systemic disease symptoms of CD include malnutrition and anemia. Iron deficiency is the main cause of anemia in CD as a consequence of dietary restrictions, malabsorption, and intestinal bleeding. People at risk for iron deficiency are also at risk for RLS. The study showed that current systemic iron deficiency was not associated with RLS in patients with CD, but significantly more patients with CD and RLS reported a history of iron deficiency than those without RLS symptoms.
Previous studies have demonstrated an association of small intestinal bacterial overgrowth with CD in the ileum. The results of this study suggest ileum involvement in patients with CD may be a risk factor for RLS. The researchers hypothesized that inflammation attributable to other systemic and GI-related disorders, such as CD, results in an iron deficiency in the CNS, causing RLS.
Researchers hope the association of RLS with CD may lead to an understanding of fatigue and sleep disturbances associated with CD. Further studies are warranted to evaluate the potential impact that RLS has on the quality of life in patients with CD using the international RLS rating scale.
The National Digestive Diseases Information Clearinghouse, an information dissemination service of the National Institute of Diabetes and Digestive and Kidney Diseases, has fact sheets and easy-to-read booklets about digestive disorders, including CD. For more information and to obtain copies, visit www.digestive.niddk.nih.gov.
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