Management of Chronic Diarrhoea
The management of chronic diarrhoea requires a systematic diagnostic approach followed by targeted treatment of the underlying cause, with symptomatic therapy including loperamide as first-line treatment for non-infectious chronic diarrhoea. 1, 2
Diagnostic Approach
Initial Assessment
- Stool characteristics: Categorize as watery, fatty (malabsorptive), or inflammatory 3
- Duration: Confirm >4 weeks of symptoms 1
- Key history elements:
- Family history of neoplastic, inflammatory bowel or coeliac disease
- Previous surgery (especially intestinal resections)
- Previous pancreatic disease
- Systemic diseases (thyroid disorders, diabetes)
- Alcohol consumption
- Dietary factors (caffeine, milk products, food additives)
- Medication review 1
First-line Investigations
- Blood tests: Full blood count, ESR, electrolytes, liver function, iron studies, vitamin B12, folate, thyroid function 1
- Serological testing: Anti-tissue transglutaminase antibodies for coeliac disease 1, 4
- Stool tests: Ova, cysts, parasites, bacterial pathogens, C. difficile toxin, fecal calprotectin 1, 2
Second-line Investigations
- Colonoscopy with biopsies: Recommended for patients >45 years, or with alarm features (rectal bleeding, weight loss) 1, 2
- Distal duodenal biopsies: For suspected small bowel malabsorption despite negative coeliac serology 1
- Specific tests based on suspected etiology:
Treatment Approach
1. Treat Underlying Cause
- Coeliac disease: Strict gluten-free diet 2
- Bile acid malabsorption: Cholestyramine or other bile acid sequestrants 2
- Microscopic colitis: Budesonide 2
- Small bowel bacterial overgrowth: Targeted antibiotics 2
- Pancreatic insufficiency: Pancreatic enzyme replacement therapy 2
- Inflammatory bowel disease: Disease-specific therapy 1
2. Symptomatic Management
Antidiarrheal Medications
- First-line: Loperamide 2 mg after each loose stool (maximum 16 mg daily) 2
- Caution: Avoid in high fever, bloody diarrhea, severe vomiting, or dehydration 2
Fluid and Electrolyte Management
- Mild-moderate dehydration: Glucose-containing drinks or electrolyte-rich soups 2
- Severe dehydration: Oral rehydration solution or IV fluids if needed 2
Dietary Modifications
- General recommendations:
3. Special Situations
Post-Surgical Diarrhea
- Identify mechanism: bile salt malabsorption, bacterial overgrowth, or reduced absorptive capacity 1
- Targeted therapy based on mechanism 1
Radiation-Induced Diarrhea
- Acute: Loperamide (4 mg initial dose, then 2 mg every 4 hours, max 16 mg daily) 2
- Chronic: Dietary counseling, colesevelam for bile salt malabsorption, antidiarrheals 2
Fecal Incontinence with Diarrhea
- Rule out fecal impaction with overflow diarrhea, especially in elderly 1
- Consider anorectal manometry and endoanal ultrasonography after conservative measures fail 1
Follow-up and Monitoring
- Reassess in 3-6 weeks to evaluate treatment effectiveness 2
- Monitor for alarm features: nocturnal diarrhea, unintentional weight loss, blood in stool 2
- Consider alternative diagnoses if initial treatment is ineffective 2
Common Pitfalls to Avoid
- Failing to exclude infectious causes before symptomatic treatment 2
- Overlooking bile acid diarrhea, which is common but frequently underdiagnosed 2
- Using antidiarrheal agents in contraindicated situations (severe illness, obstruction, fever) 2
- Inadequate investigation of alarm symptoms 2
- Relying on three-day fecal fat test, which is unreliable and no longer recommended 1
When chronic diarrhea persists despite thorough investigation and empiric treatment, symptomatic management should be continued while considering referral to a gastroenterology specialist for further evaluation 1.