[Pathophysiology of tropical diarrhea]

Abstract

All cases of diarrhea involve increased fecal excretion of water. Understanding the mechanisms of infectious diarrhea requires review of the physiology of water and electrolyte absorption. Every day, 8 to 9 liters of fluid flow into the intestine, most of it reabsorbed in the small bowel. There are 2 main types of infectious diarrhea: secretory noninvasive diarrhea, such as cholera, due to impairment of water absorption mechanisms in the small bowel and inducing watery stools and dehydration; and enteroinvasive diarrhea, due to alteration of the colonic mucosa, inducing dysentery. Most cases of infectious diarrhea are acute. Some pathogens, mainly parasites, can induce chronic diarrhea. A HIV serology is then warranted. Some patients develop chronic irritable bowel syndrome after acute gastroenteritis.