Brown bowel syndrome: a systematic review

Brown bowel syndrome (BBS) is a rare disorder characterized by brown pigmentation of the intestinal wall, thought to be a consequence of lipofuscin accumulation. Celiac disease and vitamin E deficiency have been postulated to be risk factors. We systematically searched PubMed, Embase, Web of Science and Cochrane to identify all case reports and abstracts reporting clinical information on patients with a confirmed diagnosis of BBS. Forty-two studies met our inclusion criteria, including 63 patients with confirmed BBS. The most common symptoms of BBS were diarrhea (50.8%) and malnutrition (50.8%), followed by abdominal pain (39.7%) and vomiting (22.2%). BBS patients with celiac disease who presented with similar symptoms to non-celiac patients were significantly less likely to be hypoalbuminemic (15.4 vs. 45.5%) and showed a non-significant trend towards a higher mortality rate (36.4% vs. 15.4%). Nineteen (31.7%) BBS patients were also vitamin E deficient. The clinical presentation and outcomes in BBS patients with vitamin E deficiency and celiac disease were similar to those without vitamin E deficiency and celiac disease. Further studies are warranted to better define the diagnostic-therapeutic approach to patients with BBS.