Treatment of Chronic Diarrhea
The first-line treatment for chronic diarrhea is loperamide, which is FDA-approved for the control and symptomatic relief of chronic diarrhea in adults, particularly when associated with inflammatory bowel disease. 1
Initial Assessment and Diagnosis
- Chronic diarrhea is defined as abnormal passage of ≥3 loose stools per day for more than 4 weeks 2
- Initial screening blood tests should include full blood count, ferritin, tissue transglutaminase/EMA, and thyroid function test, as well as stool tests for inflammation (faecal calprotectin) 3
- Screening for coeliac disease using serological tests (tissue transglutaminase or EMA) is mandatory due to their high sensitivity and specificity 3
- Colonoscopy with biopsies of right and left colon (not rectal) is recommended to exclude microscopic colitis 3
- Testing for bile acid diarrhea should be performed using SeHCAT testing or 7α-hydroxy-4-cholesten-3-one in patients with IBS-diarrhea, functional diarrhea, and Crohn's disease without inflammation 3
Pharmacological Treatment
- Loperamide is the drug of choice for chronic diarrhea, with flexible dosing according to loose bowel movements 3, 1
- For bile acid diarrhea, cholestyramine is suggested as initial therapy, with alternate bile acid sequestrants when tolerability is an issue 3
- Maintenance bile acid sequestrant therapy should be given at the lowest effective dose, with a trial of intermittent, on-demand administration 3
- Alternative antidiarrheal agents should be considered if bile acid sequestrants are not tolerated, particularly in patients with extensive ileal Crohn's disease or resection 3
Dietary Management
- Maintain adequate fluid intake as indicated by thirst, using drinks containing glucose (such as lemonades, sweet sodas, or fruit juices) or soups rich in electrolytes 3
- Consumption of solid food should be guided by appetite, with small light meals recommended 3
- Avoid fatty, heavy, spicy, or stimulant foods (including caffeine and cola drinks) 3
- Consider avoidance of lactose-containing foods (such as milk) in more prolonged episodes of diarrhea 3
- Dietary modifications should be tailored to the underlying cause of chronic diarrhea 2, 4
Cause-Specific Treatments
- For inflammatory diarrhea, budesonide may be beneficial 2
- For bile acid malabsorption, bile acid sequestrants like cholestyramine are recommended 3, 2
- For secretory diarrhea due to specific endocrine disorders, targeted therapy addressing the underlying condition is necessary 5
- For osmotic diarrhea from carbohydrate malabsorption, elimination of the offending carbohydrate from the diet is recommended 5
- For fatty diarrhea due to pancreatic exocrine insufficiency, pancreatic enzyme replacement therapy is indicated 5
Special Considerations
- In patients with functional bowel disorders (IBS-diarrhea), a positive diagnosis should be made following basic blood and stool screening tests 3
- In patients with chronic diarrhea over 45 years old, appropriate lower gastrointestinal investigation (colonoscopy or flexible sigmoidoscopy with barium enema) is essential to exclude colorectal cancer 3
- For immunocompromised patients, investigation for chronic infections with pathogens such as cryptosporidia or norovirus should be performed 3
- Rehydration (oral or parenteral) is essential for patients with large-volume diarrhea to prevent dehydration and electrolyte imbalances 2
Common Pitfalls and Caveats
- Empirical use of antimicrobials for all diarrheal episodes is not recommended due to increasing drug resistance 3
- Loperamide overdose can cause serious cardiac adverse reactions, including QT/QTc interval prolongation and arrhythmias 2
- Failure to recognize bile acid diarrhea as a common but frequently underdiagnosed cause of chronic diarrhea 3
- Inadequate investigation of alarm features such as rectal bleeding, weight loss, or anemia which may indicate inflammatory bowel disease or colorectal cancer 3, 6
- Neglecting to consider medication side effects as a potential cause of chronic diarrhea 7