What is the approach to managing chronic diarrhoea?

Management of Chronic Diarrhoea: A Structured Approach

The management of chronic diarrhoea requires a systematic diagnostic approach followed by targeted treatment based on the underlying cause, with loperamide being the first-line symptomatic treatment for uncomplicated cases.

Initial Assessment

Definition and Classification

• Chronic diarrhoea is defined as the abnormal passage of loose or liquid stools more than three times daily and/or stool volume greater than 200g/day for more than 4 weeks 1
• Use the Bristol Stool Chart to assess consistency (type 5 and above indicates diarrhoea) 1

Key History Elements

• Duration and pattern of symptoms
• Stool characteristics (frequency, consistency, volume, presence of blood)
• Nocturnal diarrhoea (suggests organic disease)
• Recent travel history
• Medication review (including antibiotics)
• Previous surgeries (especially intestinal resections)
• Family history of IBD, coeliac disease, or colorectal cancer
• Dietary factors (lactose, fructose, sorbitol, high FODMAP foods)
• Associated symptoms (weight loss, abdominal pain, fever)

Diagnostic Algorithm

Primary Care Investigations

1. Blood tests:

   • Full blood count
   • C-reactive protein and ESR
   • Electrolytes and renal function
   • Liver function tests
   • Thyroid function tests
   • Coeliac serology (tissue transglutaminase antibodies)

2. Stool tests:

   • Microscopy, culture, and sensitivity
   • Clostridium difficile toxin
   • Faecal calprotectin (to detect inflammation)
   • Faecal occult blood test

Secondary Care Investigations (Based on Initial Findings)

1. Endoscopic evaluation:

   • Colonoscopy with ileal intubation and biopsies (particularly in patients >45 years)
   • Upper GI endoscopy with duodenal biopsies (if coeliac disease suspected)

2. Specialized tests (as indicated):

   • SeHCAT scan for bile acid malabsorption
   • Hydrogen/methane breath tests for carbohydrate malabsorption or bacterial overgrowth
   • Pancreatic function tests
   • CT or MRI enterography for small bowel assessment

Treatment Approach

Symptomatic Management

1. First-line antidiarrheal:

   • Loperamide: Start with 4 mg initially, followed by 2 mg after each loose stool (maximum 16 mg/day) 1, 2
   • Continue until diarrhoea resolves for at least 12 hours 2

2. Dietary modifications:

   • BRAT diet (Bananas, Rice, Applesauce, Toast) during acute episodes 2
   • Avoid spices, coffee, alcohol, and reduce insoluble fiber intake 2
   • Consider lactose restriction if lactose intolerance suspected
   • Low FODMAP diet trial if functional cause suspected 3

3. Hydration:

   • Ensure adequate oral hydration and electrolyte replacement 2

Cause-Specific Treatment

1. Inflammatory Bowel Disease:

   • Anti-inflammatory medications (5-ASA, corticosteroids)
   • Immunomodulators or biologics as indicated

2. Microscopic Colitis:

   • Budesonide 9 mg daily for induction of remission 1

3. Bile Acid Malabsorption:

   • Bile acid sequestrants (cholestyramine, colestipol, colesevelam) 1

4. Small Bowel Bacterial Overgrowth:

   • Antibiotics (rifaximin preferred due to minimal systemic absorption) 4
   • Treat underlying causes

5. Coeliac Disease:

   • Strict gluten-free diet

6. Chemotherapy-induced Diarrhoea:

   • For uncomplicated diarrhoea: loperamide as above 1
   • For complicated diarrhoea: hospitalization, IV fluids, antibiotics, and octreotide (100-150 μg SC/IV three times daily) 1

7. Functional Diarrhoea/IBS-D:

   • Loperamide for symptom control
   • Consider ispaghula husk (psyllium) with calcium as an alternative 5
   • 5-HT3 antagonists or tricyclic antidepressants for refractory cases 6

Monitoring and Follow-up

• Track stool frequency and consistency during treatment
• Review after 4-6 weeks of initial treatment
• If no improvement or worsening symptoms, reassess diagnosis and consider additional investigations
• Monitor for complications such as dehydration, electrolyte imbalances, and malnutrition

Red Flags Requiring Urgent Attention

• Severe dehydration or electrolyte disturbances
• Significant weight loss
• Bloody diarrhoea
• Fever
• Severe abdominal pain
• Diarrhoea in immunocompromised patients
• Chemotherapy-induced diarrhoea with signs of enterocolitis 1

Special Considerations

• Elderly patients: More susceptible to dehydration, electrolyte imbalances, renal function decline, and malnutrition 1
• Cancer patients: Consider chemotherapy-related causes; 74% of patients >65 years report diarrhoea during chemotherapy 1
• Post-surgical patients: Consider bile acid malabsorption, small bowel bacterial overgrowth, or dumping syndrome 1, 6

Remember that chronic diarrhoea significantly impacts quality of life through stool frequency, urgency, and potential incontinence. Targeted treatment based on accurate diagnosis is essential for improving patient outcomes and reducing morbidity.