What triggers microscopic colitis?

Triggers of Microscopic Colitis

Medications are the most well-established triggers of microscopic colitis, particularly NSAIDs, PPIs, SSRIs, and statins, which should be identified and discontinued in patients with this condition. 1, 2

Key Medication Triggers

• Non-steroidal anti-inflammatory drugs (NSAIDs) - Associated with both collagenous and lymphocytic colitis 1, 2
• Proton pump inhibitors (PPIs) - Strongly associated with microscopic colitis development 1, 2
• Selective serotonin reuptake inhibitors (SSRIs) - Particularly sertraline has shown significant association 1, 2, 3
• Statins (HMG-CoA reductase inhibitors) - Identified as potential triggers 1, 2, 3

Other Important Triggers

Patient-Related Factors

• Female sex - Women are more commonly affected (77% of collagenous colitis, 68% of lymphocytic colitis) 1
• Age ≥50 years - Mean age at presentation is around 60, though 25% of cases occur in patients under 45 1
• Cigarette smoking - Recognized as a significant risk factor 4, 5
• Alcohol consumption - Associated with increased risk 5

Associated Conditions

• Autoimmune diseases - Particularly rheumatic disease and thyroid disease 1
• Bile acid diarrhea - Present in 41% of collagenous colitis and 29% of lymphocytic colitis cases 1, 2
• Celiac disease - Found in 5-7% of microscopic colitis patients 1, 2
• Select gastrointestinal infections - Can trigger disease onset 1, 5

Pathophysiological Mechanisms

Microscopic colitis appears to result from a dysregulated immune response to various noxious luminal agents in genetically predisposed individuals 6. The triggers work through several mechanisms:

• Altered intestinal permeability - Medications and other triggers may disrupt the epithelial barrier
• Immune system activation - Leads to inflammation and characteristic histological changes
• Disruption of gut microbiota - May contribute to disease development

Clinical Implications

When evaluating a patient with suspected microscopic colitis:

1. Conduct thorough medication review - Focus on NSAIDs, PPIs, SSRIs, and statins
2. Screen for associated conditions - Particularly bile acid diarrhea and celiac disease
3. Assess modifiable risk factors - Especially cigarette smoking and alcohol consumption

Management Approach

1. Identify and discontinue potential medication triggers when possible 2
2. Consider bile acid sequestrants in patients with concurrent bile acid diarrhea 2
3. Initiate budesonide as first-line therapy (9 mg daily for 8 weeks) 2
4. Address modifiable risk factors like smoking cessation 4

Common Pitfalls to Avoid

• Failing to identify medication triggers - Thorough medication history is essential
• Overlooking associated conditions like bile acid diarrhea or celiac disease
• Neglecting to obtain biopsies from multiple segments of the colon during diagnosis 2
• Continuing potential medication triggers in patients with refractory symptoms 2

Understanding these triggers is crucial for both diagnosis and management of microscopic colitis, as eliminating triggers can significantly improve outcomes and reduce the need for pharmacological interventions.