What is chronic diarrhea?
In resource-rich countries, the common causes of chronic diarrhea are:
- irritable bowel syndrome (IBS)
- inflammatory bowel disease
- malabsorption syndromes (lactose intolerance and celiac disease)
- chronic infections (especially in the immunocompromised)
Chronic diarrhea puts patients at risk for dehydration, hypovolemia, electrolyte disturbances, and anal fissures and other local irritations.
Irritable Bowel Syndrome
IBS typically presents with abdominal pain and various bowel habits, such as alternating diarrhea and constipation, or normal bowel movements with alternating diarrhea and constipation. Half of those with IBS have mucus discharge. The type of IBS is associated with functional bowel habits, such as IBS with predominant diarrhea or IBS with mixed bowel conditions.
Many medications list diarrhea in their side effects. These can be due to alteration in flora, bowel motility, colonic overhydration, or allergic reactions.
Inflammatory Bowel Disease (IBS)
IBS is most commonly associated with Crohn disease and ulcerative colitis (UC), but it can refer to any intestinal inflammatory condition.
- Crohn disease: inflammation can involve any and all of the entire gastrointestinal tract from mouth to anus. It causes diarrhea, abdominal pain, and fever. There can be bloody stools, but this is more common with ulcerative colitis.
- Ulcerative colitis: this can have varying degrees of severity. Mild disease involves the rectum or rectosigmoid colon; rectal bleeding and mucus passage are associated with diarrhea, but constipation can appear from time to time. Moderate UC involves more than the end of the colon, going up to the left upper quadrant of the abdomen–where the descending colon begins. Frequent diarrheic, bloody stools can number 10/day and cause a mild anemia and low grade fever. Severe disease involves much of the entire large colon.
Impairment of absorption from the intestines can be hereditary or develop as a consequence of Crohn disease, celiac disease, or surgical resection. Maldigestion is the impairment in the production or quality of digestive juices. Malabsorption syndrome covers a variety of disorders:
- Lactose intolerance
- Celiac disease
- Small bowel bacterial overgrowth
- Chronic pancreatitis
Chronic infections should be considered if there is a history of travel, antibiotics, or HIV infection.