Case 22.2
FINAL PATHOLOGIC DIAGNOSIS
COLON, LINEAR ULCER AT SPLENIC FLEXURE, BIOPSY:
– FEATURES OF COLLAGENOUS COLITIS (SEE COMMENT)
Comment
The biopsy shows chronic colitis characterized by increased numbers of intraepithelial lymphocytes, increased chronic inflammation in the lamina propria without crypt architectural distortion, and an irregular/ thickened subepithelial collagen layer. A trichrome stain highlights thickening of the subepithelial collagen layer.
A CT angiogram was also obtained which showed mild atherosclerosis without significant narrowing of the superior and inferior mesenteric arteries.
What would be your next steps in management? (select all items that you would recommend)
Stop naproxen and aspirin
NSAIDs are commonly implicated as causing or triggering flares of microscopic colitis. Therefore, stopping naproxen should be recommended. However, given her significant cardiovascular disease including history of cardiac stenting, it would be prudent to discuss with her cardiologist prior to recommending stopping aspirin.
Stop naproxen but continue aspirin
NSAIDs are commonly implicated as causing or triggering flares of microscopic colitis. Therefore, stopping naproxen should be recommended. Given her significant cardiovascular disease requiring stenting, continuing aspirin is likely warranted. It may be worth discussing with her cardiologist whether an alternative anti-platelet agent such as clopidogrel should be substituted for aspirin if her collagenous colitis does not resolve with initial treatment.
Refer to vascular surgery for mesenteric artery revascularization
Colonic ischemia should be considered on the differential of linear colonic ulcers. This patient certainly has risk factors for colonic ischemia given her cardiovascular disease. However, the CT angiogram did not suggest significant arterial narrowing and the biopsy supports a diagnosis of collagenous colitis rather than ischemia.
Delayed release budesonide 9 mg daily
Budesonide is a first-line agent for microscopic colitis. Given active disease with colonic ulcers, treatment is indicated. The usual course is 9 mg daily for at least 8 weeks followed by a gradual taper.
Prednisone 40 mg daily
Prednisone is an option for treatment of microscopic colitis if budesonide is not available, but it appears to have lower response rate and is associated with more side effects. Unlike prednisone, budesonide has extensive first-pass hepatic metabolism which limits systemic exposure to glucocorticoid.
Cholestyramine 4 g four times per day
Cholestyramine is a second-line agent for microscopic colitis for patients in whom diarrhea persists despite budesonide. There seems to be an increased rate of concurrent bile acid malabsorption in microscopic colitis, though the reason for this is unclear as the ileum is usually unaffected. As this patient does not have diarrhea and has not yet tried budesonide, cholestyramine is not currently indicated.
Polyethylene glycol and fiber supplement
As this patient has constipation and diverticulosis, these are both reasonable recommendations.
Loperamide
Diarrhea is the most common symptom of microscopic colitis, and loperamide alone may be used in mild cases. However, this patient has constipation rather than diarrhea so loperamide is not appropriate.
Smoking cessation
Smoking is associated with significantly increased risk of microscopic colitis and is associated with earlier age of onset. Smoking cessation should always be recommended.