Cryptogenic Multifocal Ulcerous Stenosing Enteritis (CMUSE) in a Patient With Microscopic Colitis
Background:
The differential diagnosis for terminal ileal strictures is broad, including common conditions such as chronic NSAID use, Crohn’s disease, ischemia, prior radiation exposure, or prior intraabdominal surgery. Here, we present a case involving an underrecognized cause of inflammatory small bowel stricture.
Methods:
An 86-year-old female presented to a referral center seeking a second opinion regarding recurrent episodes of small bowel obstruction. Her medical history was significant for longstanding history of watery diarrhea which had previously been attributed to lymphocytic colitis, for which she had been taking oral budesonide for many years; and hypertension, on losartan. For the past five years, however, she had been suffering from recurrent episodes of small bowel obstruction which were increasing in frequency. Concurrently, she had lost more than 20 pounds over the past two years prior to initial consultation. She had no history of previous abdominal surgeries or radiation, was a lifetime non-smoker, and denied use of NSAIDs. Each episode of small bowel obstruction was managed conservatively in the hospital, with intravenous resuscitation and nasogastric tube decompression. Multiple CTs had demonstrated multifocal small bowel strictures which were most prominent in the distal terminal ileum, although upper endoscopy with examination and biopsy of the terminal ileum had repeatedly been without diagnostic abnormality. At the time of initial consultation, the patient underwent PET-DOTATE scan which was without any evidence of lymphoma or neuroendocrine tumor.
Results:
Double balloon enteroscopy was unable to reach any areas of stricturing in the terminal ileum. At the time, she elected to defer any further evaluation given that she had remained relatively asymptomatic between episodes of bowel obstruction. Subsequently, she experienced rapid weight loss (more than 50 pounds in the following 4 months) and even more frequent episodes of small bowel obstruction (occurring multiple times monthly). Losartan was discontinued due to concern that it may be contributing to intermittent bowel-isolated angioedema, but symptoms did not resolve. She underwent MR enterography which revealed several apparent areas of focal enhancement and narrowing involving parts of the ileum, in a pattern suggestive of cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). A repeat double balloon enteroscopy was able to visualize ulcerated strictures in the terminal ileum which were dilated and biopsied. Pathology revealed evidence of active ileitis without granulomas or dysplasia. She has since been managed with oral prednisone (initially at 20 mg daily, tapered over time to a maintenance dose of 10 mg daily). With this, she has been free from any episodes of small bowel obstruction and successfully regained 15 pounds over the first 5 months of treatment.
Conclusions:
CMUSE is a well-described but poorly understood disease characterized by chronic or relapsing obstructive symptoms caused by fibrous strictures in the small bowel. A diagnosis requires the presence of multiple strictures, < 4 cm apart, in a patient for whom more common etiologies have been excluded. Most patients are steroid-responsive, and there is very limited experience with the use of steroid-sparing agents, though vedolizumab has demonstrated success in isolated case reports.
