Pathophysiology, Evaluation, and Management of Chronic Watery Diarrhea Michael Camilleri, Joseph H. Sellin, Kim E. Barrett  Gastroenterology  Volume 152, Issue 3, Pages 515-532.e2 (February 2017) DOI: 10.1053/j.gastro.2016.10.014 Copyright © 2017 AGA Institute Terms and Conditions

Figure 1 Cellular mechanisms accounting for intestinal absorption and secretion. Factors that reduce the amount or function of a specific transporter are shown in red boxes; those that increase levels of activity are shown in green boxes. Long vertical arrows indicate the paracellular absorption or secretion of water, with or without an appropriate counterion. LPA, lysophosphatidic acid; SI, small intestine; TK, tyrosine kinase. Gastroenterology 2017 152, 515-532.e2DOI: (10.1053/j.gastro.2016.10.014) Copyright © 2017 AGA Institute Terms and Conditions

Figure 2 Interaction of mechanisms in chronic watery diarrhea. Although most reductionist research models focus on a single parameter of intestinal function, in fact there is an intricate network of agonists and effectors with a promiscuous interaction among autocrine, luminal, paracrine, immune, neural, and endocrine (ALPINES) inputs that may alter the paracellular pathway, epithelial cell function, intestinal smooth muscle, and blood flow. Diarrhea can result from a change in one or many of these pathways and alterations in permeability, transport, and motility. Figure adapted with permission from Schiller and Sellin.187 Gastroenterology 2017 152, 515-532.e2DOI: (10.1053/j.gastro.2016.10.014) Copyright © 2017 AGA Institute Terms and Conditions

Figure 3 Algorithm for management of chronic diarrhea. Patients undergo an initial evaluation based on different symptom presentations, leading to selection of patients for imaging, biopsy analysis, and limited screens for organic diseases. Alb, albumin; BA, bile acid; BM, bowel movement; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; Hb, hemoglobin; MCH, mean corpuscular hemoglobin; MCV, mean corpuscular volume; osm, osmolality; Rx, prescription; TTG, tissue transglutaminase; vol, volume. Gastroenterology 2017 152, 515-532.e2DOI: (10.1053/j.gastro.2016.10.014) Copyright © 2017 AGA Institute Terms and Conditions