Introduction

CLINICAL NUTRITION 3(2+1)
Lesson 15: Diarrhoea

Introduction

Diarrhoea is the passage of three or more loose or liquid stools per day, or more frequently than is normal for the individual. It is usually a symptom of gastrointestinal infection, which can be caused by a variety of bacterial, viral and parasitic organisms. Infection is spread through contaminated food or drinking-water, or from person to person as a result of poor hygiene.

Diarrhoea is an increase in frequency, volume or fluidity of stools

It may be secretory diarrhea which results when excess water and electrolytes are actively transported into the lumen of the intestines. Osmatic diarrhea results when water is retained in the intestinal lumen by osmotically active agents. The rate of transit through the gut determines the time available for intestinal absorption of water and very rapid transit can result in diarrhea. The maximum absorptive capacity of the colon is only 4 l/day, so if volumes of fluid greater than this enter the small intestine, diarrhea will result eventhough the colonic function is normal. The small intestine secretes about 1 l/day of fluids, but this can increase to as much as 20 l/day under certain conditions. Thus large volume diarrhoea indicates dysfunction of the small intestine.

Both functional and organic factors can lead to diarrhea. Certain emotional factors affecting neuromuscular activity can also lead to diarrhea. For example nervousness before an examination or interview can lead to functional diarrhea. Diarrhoea is commonly seen in organic diseases affecting the intestines, like Chron’s disease, ulcerative colitis etc.

Small intestinal infection is indicated by extremely watery stools.

Thick, more frequently passed stools indicate infection of the colon.

Frothy stools show that carbohydrates have not been digested properly. When proteins are not digested the stools are alkaline and foul smelling. Clay coloured or pale stools indicate steatorrhoea or presence of fat in the stools.

Loss of excessive body water through diarrhea could lead to dehydration and electrolyte loss, especially loss of potassium. Both need to be replaced in order to avert a life threatening situation.

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Last modified: Friday, 4 November 2011, 7:19 AM