Diarrhea
| Overview |
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- Diarrhea is extremely common all over the world and more than a billion individuals encounter a bout of diarrhea every year. The causes of diarrhea can be completely self-limiting or may be a manifestation of serious underlying disease; therefore, proper diagnosis of diarrhea is an absolutely critical clinical skill.
| Definition |
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- Diarrhea is designated by a very loose clinical definition and depends on the typical diet of a region and the hospital at which you work. In western countries more than 3 bowel movements/day with a total weight greater than 200g of abnormally liquid or unformed feces may indicate diarrhea.
| Basic Pathophysiology |
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- Overview
- Diarrhea can be the result of three basic pathophysiological processes. However, each process can be the result of any number of different etiologies.
- Increased Intestinal Secretion
- As discussed in Small Intestine Secretion and Large Intestine Secretion, the intestines normally secrete nearly 9-10L of fluid/day which must be resorbed. Dramatic increases in intestinal secretion can easily overwhelm the capacity of GI Water and Electrolyte Absorption and thus result in diarrhea.
- Decreased GI Absorption
- Reductions in the capacity of the GI System to digest and absorb nutrients and fluids can easily result in a state of diarrhea.
- Abnormal GI Motility
- Processes of GI Digestion and Absorption of nutrients and fluids require time to occur. Therefore, accelerated GI Motility may not provide time for sufficient resorption of nutrients and fluids, thus causing diarrhea.
| Specific Pathophysiologies and Subtopics |
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- Overview
- Unfortunately, no subcategorization of diarrhea will be completely satisfactory as a single etiology can cause diarrhea by multiple pathophysiological mechanisms, and a single pathophysiological mechanism can be initiated by multiple etiologies. However, we feel that the pathophysiological categorization below will be most didactically useful.
- Diarrhea Pathophysiologies