What is the treatment for a patient with microscopic colitis causing diarrhea?

Treatment of Microscopic Colitis Causing Diarrhea

Budesonide 9 mg once daily for 6-8 weeks is the first-line treatment for microscopic colitis, with strong evidence showing it is more than twice as likely to induce clinical remission compared to no treatment and nearly twice as effective as mesalamine. 1

First-Line Therapy: Budesonide

• Start budesonide 9 mg once daily as initial therapy due to its highly favorable risk/benefit profile, convenience of once-daily dosing, and superior efficacy over all alternatives 1, 2
• Patients treated with budesonide are 2.52 times more likely to achieve clinical remission (95% CI 1.45-4.4) within 7-13 days compared to no treatment 1
• Budesonide demonstrates both clinical and histological response, with 60.9% of patients showing histologic improvement 3
• The medication is well-tolerated with low risk of serious adverse events 1

Alternative First-Line Options (When Budesonide Not Feasible)

If budesonide is contraindicated, too expensive, or patient refuses:

Mesalamine (Second Choice)

• Use mesalamine 3 g daily if budesonide therapy is not feasible 1, 2
• This is a conditional recommendation with moderate quality evidence, as it is less effective than budesonide but superior to no treatment 1
• Consider for patients with contraindications to corticosteroids or strong preference against budesonide 1

Bismuth Salicylate (Third Choice)

• Dose: 8-9 tablets divided three times daily 1
• All patients (7/7) in one small trial showed clinical response versus none in placebo group 1
• This is a conditional recommendation with low quality evidence 1, 2
• Caution: Significant pill burden for elderly patients who often take multiple medications; unknown long-term toxicity risk 1
• Reserve for patients with contraindications to corticosteroids or when cost is prohibitive 1

Prednisolone/Prednisone (Fourth Choice)

• Consider only when budesonide is not feasible and cost is the primary barrier 1
• This is a conditional recommendation with very low quality evidence 1, 2
• Caution: Significant risk of adverse events from systemic corticosteroid exposure 1
• May be appropriate when other options have failed and coexisting conditions like celiac disease have been excluded 1

Adjunctive Measures

• Identify and discontinue triggering medications when possible, including NSAIDs, proton pump inhibitors, and SSRIs 2, 4
• Antidiarrheal agents (e.g., loperamide) may be used as symptomatic therapy, though formal trial data are lacking 1

Maintenance Therapy (For Relapsing Disease)

Only offer maintenance therapy to patients who experience symptom recurrence after stopping induction therapy—up to one-third may not require it. 1

• Start budesonide 6 mg daily for maintenance, which reduces clinical relapse risk by 66% (RR 0.34,95% CI 0.19-0.6) 1, 2, 5
• Taper to the lowest effective dose in clinical practice; some patients respond to 3 mg daily or alternating 3 mg/6 mg daily 1, 5
• Continue maintenance for 6-12 months before attempting discontinuation 1, 2, 5
• Monitor for bone loss: Consider osteoporosis prevention and screening with prolonged budesonide use due to potential bone density effects despite low systemic bioavailability 1, 2, 5

Therapies NOT Recommended

• Probiotics: Not recommended (conditional recommendation, low quality evidence) 2
• Boswellia serrata: Not recommended (conditional recommendation, low quality evidence) 2
• Cholestyramine plus mesalamine combination: Not superior to mesalamine alone 2

Management of Residual Symptoms

• If symptoms persist after budesonide treatment, perform colonoscopy with biopsies to assess for normal histology, which may suggest coexisting conditions 1
• Re-evaluate for other causes of diarrhea including celiac disease, functional bowel disorders, or post-inflammatory symptoms 2
• For truly refractory disease (not addressed in guidelines), case series suggest azathioprine or anti-TNF agents may be beneficial, though prospective trial data are needed 1

Common Pitfalls

• Failing to communicate the diagnosis: 10% of patients with biopsy-confirmed microscopic colitis remain unaware of their diagnosis at 1-year follow-up 6
• Premature discontinuation: Many patients (40-46%) continue to have symptoms including fecal urgency, requiring ongoing management 6
• Not considering maintenance therapy: Patients often relapse after initial budesonide course is discontinued, necessitating maintenance dosing 7