The Medical clinics of North America
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The mechanisms by which bacterial enterotoxins cause secretory diarrheas have been well defined, and the definitions of such mechanisms have been important in developing a consistently successful therapeutic approach. The less common secretory diarrheas, caused by the interaction of hormones of tumor origin with the gut small intestinal mucosa have also been clearly defined, and their pathogenetic mechanisms are similar to those by which the cholera and E. coli enterotoxins cause secretory diarrhea. The mechanisms by which histamine and gastrin of tumor origin cause gastric hypersecretion are less clearly delineated; secretory diarrhea caused by both of these agents can be stopped by total gastrectomy without removal of the responsible tumor. The secretory diarrhea caused by villous adenomas of the colon, which does not appear to be related to a distally produced humoral agent, results in the same picture of hypokalemic acidosis that is characteristic of the nonbacterial secretory diarrheas originating in the small intestine and is cured by resection of the responsible tumor.
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Fungal infections of the gastrointestinal tract have risen to higher levels of prevalence in the past decade. Major factors accounting for this increase are social changes, such as the increased ease and frequency of travel, which exposes the individual to environmental conditions that may result in fungal infection; increasing use of antibiotic and hormonal medications by otherwise healthy persons; and improved therapy for other diseases, such as polychemotherapy of cancer with its immunosuppressive effects. Both noninvasive and invasive fungal disease of the intestinal tract in otherwise healthy individuals can be successfully treated. The invasive fungal infections in patients with severe prior underlying disease are often first diagnosed postmortem, but improvement in serologic techniques now offers a possibility of earlier diagnosis and therapeutic intervention.