- Diarrhea is caused by many viral and bacterial organisms. It is most often a minor discomfort, not life-threatening, and usually self-limited.
- The four pathophysiologic mechanisms of diarrhea have been linked to the four broad diarrheal groups, which are secretory, osmotic, exudative, and altered intestinal transit. The three mechanisms by which absorption occurs from the intestines are active transport, diffusion, and solvent drag.
- Management of diarrhea focuses on preventing excessive water and electrolyte losses, dietary care, relieving symptoms, treating curable causes, and treating secondary disorders.
- Bismuth subsalicylate is marketed for indigestion, relieving abdominal cramps, and controlling diarrhea, including traveler’s diarrhea, but may cause interactions with several components if given excessively.
- Constipation is defined as difficult or infrequent passage of stool, at times associated with straining or a feeling of incomplete defecation.
- Underlying causes of constipation should be identified when possible and corrective measures taken (e.g., alteration of diet or treatment of diseases such as hypothyroidism).
- The foundation of treatment of constipation is dietary fiber or bulk-forming laxatives that provide 20 to 25 g/day of raw fiber.
- Irritable bowel syndrome (IBS) is one of the most common GI disorders characterized by lower abdominal pain, disturbed defecation, and bloating. Many non-GI manifestations also exist with IBS. Visceral hypersensitivity is a major culprit in the pathophysiology of the disease.
- Diarrhea-predominant IBS should be managed by dietary modification and drugs such as loperamide when diet changes alone are insufficient to promote control of symptoms.
- Several drug classes are involved in the treatment of the pain associated with IBS including tricyclic compounds and the gut-selective calcium channel blockers.
On completion of the chapter, the student will be able to:
Identify the common causative organisms of bacterial and viral infectious diarrhea.
Differentiate acute from chronic diarrhea, in terms of onset and duration of symptoms.
Explain the three mechanisms of absorption from the intestines and the four general pathophysiologic mechanisms of diarrhea.
List the five therapeutic goals in the treatment of diarrhea.
List factors correlated with the prevention of diarrhea.
Discuss the various drug categories used to treat diarrheal attacks.
List the experimental drug classes that have been used to control diarrhea.
List factors correlated with self-reported constipation.
Identify common causes of constipation.
List the drugs affecting GI function that may cause constipation.
List the three general classes of laxatives and their expected onset of effect.
Discuss the proper management of constipation in terms of dietary modification and list the three bulk-forming agents.
Describe laxative abuse syndrome, including characteristics of laxative abusers, symptoms/clinical presentation, and the long-term physiologic effects of abuse.
Define irritable bowel syndrome (IBS), list the manifestations of IBS, and cite its underlying pathophysiologic causes.
Discuss the procedures used in the diagnosis of IBS.
Differentiate between constipation- and diarrhea-predominant IBS in terms of treatment options.
List drug classes used in the treatment of pain associated with IBS.
List the experimental drug classes under investigation for the treatment of IBS.
Diarrhea is a troublesome discomfort ...