Volume 129, Issue 4, Pages 1268-1273 (October 2005) Stimulated Active Potassium Secretion in a Patient With Colonic Pseudo-Obstruction: A New Mechanism of Secretory Diarrhea  Thomas G. van Dinter, Florentine C. Fuerst, Charles T. Richardson, Carol A. Santa Ana, Daniel E. Polter, John S. Fordtran, Henry J. Binder  Gastroenterology  Volume 129, Issue 4, Pages 1268-1273 (October 2005) DOI: 10.1053/j.gastro.2005.07.029 Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 1 Radiologic imaging of the abdomen and pelvis. Top: X-ray of the abdomen demonstrating massive distention of the colon with a cecal diameter of at least 12 cm. Bottom: Unenhanced computed tomographic (CT) scan of the abdomen, showing a markedly dilated rectosigmoid (diameter of 10 cm) containing a large amount of fluid. Gastroenterology 2005 129, 1268-1273DOI: (10.1053/j.gastro.2005.07.029) Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 2 The pattern of diarrhea in a patient with colonic pseudo-obstruction, from hospital days 49 through 73. Stools were quantitatively collected and analyzed for electrolytes on 11 different occasions. Gastroenterology 2005 129, 1268-1273DOI: (10.1053/j.gastro.2005.07.029) Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 3 Correlation between daily wet stool weight and daily fecal output of sodium and potassium in people with diarrhea. (A) Shows results in our patient with diarrhea and colonic pseudo-obstruction on different study days. Increased stool weight was associated with a dramatic increase in fecal potassium output but with only a small increase in fecal sodium output. (B) Shows results in different patients with classic secretory diarrhea of which increased stool weight was associated with a much greater increase in fecal sodium than in fecal potassium output. (C) Shows results in normal subjects with diarrhea because of ingestion of varying doses of polyethylene glycol 3350 (PEG). As stool weight increased, there was only a small increase in fecal sodium and potassium output. (References to case studies from which results in B and C were obtained are available from the authors by e-mail.) In this patient with diarrhea and colonic pseudo-obstruction, fecal potassium output was much higher than in classic secretory diarrhea or PEG-induced diarrhea, and fecal sodium output was even less than in normal subjects with PEG-induced diarrhea. Gastroenterology 2005 129, 1268-1273DOI: (10.1053/j.gastro.2005.07.029) Copyright © 2005 American Gastroenterological Association Terms and Conditions