The Bottom Line: The following tests were performed: (a) HLA-DQ2/DQ8 genotyping, and if positive, endoscopic biopsies from distal duodenum were obtained, and intestinal damage assessed; (b) SeHCAT (Se-homotaurocholate) abdominal retention test; (c) small bowel follow-through; and (d) hydrogen breath test (lactose, fructose + sorbitol). Gluten- or sugar-free diet, or cholestyramine was administered according to results. Functional disease was diagnosed if all tests performed were normal or if either there was no response to specific therapy or diarrhea relapsed during a 12-month follow-up.
Reference: Fernández-Bañares F, Esteve M, Salas A, Alsina M, Farré C, González C, Buxeda M, Forné M, Rosinach M, Espinós JC, Maria Viver J. Systemic evaluation of the causes of chronic watery diarrhea with functional characteristics. Am J Gastroenterol. 2007 Nov;102(11):2520-8.
Summary: Bile acid malabsorption was considered to be the cause of diarrhea in 28 (45.2%) patients, sugar malabsorption in 10 (16.1%), gluten-sensitive enteropathy in 10 (16.1%), and both bile acid and sugar malabsorption in 2 patients. Twelve (19.4%) patients remained without a specific diagnosis and were considered as functional bowel disease. Diarrhea stopped in the 50 patients after specific treatment, decreasing the daily stool number from 5.4 +/- 0.3 to 1.5 +/- 0.1 (P < 0.0005), without relapse after the 12-months follow-up.