High prevalence of small intestinal bacterial overgrowth in celiac patients with persistence of gastrointestinal symptoms after gluten withdrawal

Abstract

Objective Celiac disease is a gluten-sensitive enteropathy with a broad spectrum of clinical manifestation, and most celiac patients respond to a gluten-free diet (GFD). However, in some rare cases celiacs continue to experience GI symptoms after GFD, despite optimal adherence to diet. The aim of our study was to evaluate the causes of persistence of GI symptoms in a series of consecutive celiac patients fully compliant to GFD. Methods We studied 15 celiac patients (five men, 10 women, mean age 36.5 yr, range 24–59 yr) who continued to experience GI symptoms after at least 6–8 months of GFD (even if of less severity). Antigliadin antibody (AGA) test, antiendomysial antibody (EMA) test, and sorbitol H2-breath test (H2-BT), as well as esophagogastroduodenoscopy (EGD) with histological evaluation, were performed before starting GFD. Bioptic samples were obtained from the second duodenal portion during EGD, and histopathology was expressed according to the Marsh classification. To investigate the causes of persistence of GI symptoms in these patients, we performed AGA and EMA tests, stool examination, EGD with histological examination of small bowel mucosa, and sorbitol-, lactose-, and lactulose H2-breath tests. Results Histology improved in all patients after 6–8 months of GFD; therefore, refractory celiac disease could be excluded. One patient with Marsh II lesions was fully compliant to his diet but had mistakenly taken an antibiotic containing gluten. Two patients showed lactose malabsorption, one patient showed Giardia lamblia and one patient Ascaris lumbricoides infestation, and 10 patients showed small intestinal bacterial overgrowth (SIBO) by lactulose H2-BT. We prescribed a diet without milk or fresh milk–derived foods to the patient with lactose malabsorption; we treated the patients with parasite infestation with mebendazole 500 mg/day for 3 days for 2 consecutive wk; and we treated the patients with SIBO with rifaximin 800 mg/day for 1 wk. The patients were re-evaluated 1 month after the end of drug treatment (or after starting lactose-free diet); at this visit all patients were symptom-free. Conclusions This study showed that SIBO affects most celiacs with persistence of GI symptoms after gluten withdrawal.