Colon

General

Diarrhea / dysentery



Last author update: 1 May 2013
Last staff update: 22 December 2021

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PubMed Search: colitis dysentery

Hanni Gulwani, M.B.B.S.
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Cite this page: Gulwani H. Diarrhea / dysentery. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colondiarrheageneral.html. Accessed March 28th, 2024.
Definition / general
  • Normal intestines receive 9 liters of fluid per day (oral intake: 2 L, saliva: 1L, gastric juices: 2L, pancreatic juices: 2L, intestinal juices: 1L); most is reabsorbed in small intestine and colon
Terminology
Epidemiology
  • 12,000 deaths/year from dehydration in developing countries - 50% of all deaths before age 5
  • Affects 40% of U.S. population - #2 in attack rates in U.S. after common cold
Clinical features
Deranged motility:
  • Improper gut neuromuscular function causes decreased transit time
  • Due to surgical resection of gut, irritable bowel syndrome (neural dysfunction), hyperthyroidism, diabetic neuropathy, carcinoid syndrome
  • Decreased motility due to small bowel diverticula, blind loop, bacterial overgrowth
Exudative disease:
  • Purulent bloody stools, persist with fasting; caused by bacteria (Salmonella, Shigella, Campylobacter), Entamoeba histolytica, idiopathic inflammatory bowel disease, typhlitis (neutropenic colitis in immunosuppressed)
Malabsorption: Osmotic diarrhea:
  • Gut luminal solutes create high stool osmolality, abates with fasting
  • Stool osmolality > electrolyte concentration by 50 mOsm
  • Associated with lactase deficiency, lactulose therapy, gut lavage, antacids, primary bile acid malabsorption
Secretory diarrhea:
  • > 500 mL of fluid stool per day, isotonic with plasma, persists during fasting
  • Infectious (viral damage to epithelium): rotavirus, Norwalk virus, enteric adenoviruses, calicivirus, astrovirus
  • Infectious (enterotoxin): Vibrio cholera, E. coli, Bacillus cereus, Clostridium perfringens
  • Neoplastic: tumor production of peptides, villous adenoma in distal colon
  • Excessive laxatives
Diagrams / tables

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Chronic diarrhea

Microscopic (histologic) description
  • Patchy lesions with variable villus abnormality, rarely severe
  • Increased chronic and acute inflammatory infiltrate in epithelium and lamina propria
  • Small intestinal bacterial overgrowth: common cause of chronic diarrhea and malabsorption with either villous blunting or normal duodenal biopsy (Arch Pathol Lab Med 2010;134:264)
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