The functional consequences of colectomy.

The colon plays a decisive role in salt and water conservation in the intact human, normally removing from the terminal intestine approximately one liter of isotonic fluid that escapes small bowel absorption. The primary purpose of this colon function is probably to prevent extracellular fluid volume depletion and only incidentally to produce a normal solid stool. The patient with an ileostomy can partly adapt to replace the absorptive capacity lost after colectomy but is still vulnerable if salt and water intake ceases completely. In contrast, patients with ileorectostomies and some patients with continent ileostomies can almost totally adapt to loss of the colon. These findings suggest that the ileal mucosa can adapt under certain conditions to absorb at rates and concentrations previously thought impossible. This property of ileal mucosa might be utilized in the future to significantly improve the condition of patients who require total colectomy.