Rare Microscopic Colitis in IBD Associated With More Active Inflammation, Study Reports

Rare Microscopic Colitis in IBD Associated With More Active Inflammation, Study Reports

Lymphocytic colitis (LC) and collagenous colitis (CC) occur rarely in people with inflammatory bowel disease (IBD) but are linked with more active inflammation, a study reports.

The findings highlight the need to identify LC/CC in patients so that they can receive appropriate healthcare management.

The study, “Clinicopathological significance of lymphocytic colitis/collagenous colitis in inflammatory bowel disease,” was published in the journal Human Pathology.

LC and CC are two types of IBD characterized by inflammation of the colon, the last portion of the bowel that ends at the anus. LC/CC are commonly called microscopic colitis since their diagnosis requires examination of tissue under a microscope. Patients with these conditions often have chronic watery diarrhea, with normal or almost normal colonoscopy, and women between 60 and 70 years of age are the more commonly affected.

In the study, researchers set out to characterize the clinical features of patients with microscopic colitis before or after the onset of IBD. The team also evaluated the impact of LC/CC on IBD.

“Although there are some case reports that have described patients with LC/CC evolving into [ulcerative colitis/Crohn’s disease] later in life or vice versa, the correlation between LC/CC and IBD has not been well defined,” the team wrote.

Using the surgical pathology files at the Mayo Clinic, in Rochester, Minnesota, the researchers identified 27 patients diagnosed with one of the two major forms of IBD — ulcerative colitis or Crohn’s disease — who developed microscopic colitis. Patients were separated into two categories: those who developed LC/CC before IBD and those who developed it after.

In total, 10 patients with initial diagnoses of LC (two patients)/CC (eight patients) evolved into ulcerative colitis (seven patients) or Crohn’s disease (three patients) after a median interval of 14 months (range of two months to three years and eight months). The median age at initial microscopic colitis diagnosis was 66.5 years.

The most common clinical scenario was patients progressing from CC to ulcerative colitis or Crohn’s disease.

Five patients who developed ulcerative colitis from a previous CC diagnosis showed enhanced diarrhea with or without blood (five patients), abdominal pain (three patients), and weight loss (one patient). In endoscopy evaluation, pancolitis (a form of ulcerative colitis that affects the entire large intestine) was seen in four patients, diffuse inflammation in the left side colon in one patient, and bleeding ulcers in two patients. Two of the five patients underwent panproctocolectomy, a surgery to remove the entire colon, rectum, and anal canal due to hard-to-treat ulcerative colitis.

Two out of three patients who developed Crohn’s disease from CC showed increased diarrhea with abdominal pain, and one patient experienced weight loss. Endoscopy analysis revealed signs of ulceration (one patient), diffuse colitis (one patient), and ileitis (inflammation of the ileum, a portion of the small intestine, in one patient). Following treatment, the three Crohn’s disease patients entered remission.

In turn, 17 patients with initial diagnosis of ulcerative colitis (11 patients) or Crohn’s disease (six patients) developed LC (six patients)/CC (11 patients) after a median interval of nine years (range of 15 months to 45 years and eight months).

The IBD diagnosis occurred at a mean average age of 34 years, which was significantly younger than the patients in the group first diagnosed with LC/CC, the researchers noted. Also, the interval between the diagnoses was longer — median nine years — than those described in the other group (median 14 months).

Among the 11 ulcerative colitis patients, eight eventually evolved into CC within a median period of nine years and five months. They all underwent the typical flare of ulcerative colitis before developing CC. Two patients underwent total remission after treatment for CC, three had persistent symptoms of mild diarrhea (considered a partial resolution), and three underwent panproctocolectomy due to hard-to-treat recurrent ulcerative colitis.

Three ulcerative colitis patients developed LC after a median time of 38.5 years.

Among the six Crohn’s disease patients, three developed LC after a median of three years and one month, and the other three were diagnosed with CC following six years and five months.

The researchers also identified a third pattern — in a total of seven patients — where a third diagnosis of LC/CC to IBD and then to LC/CC was found, or conversion between LC and CC after IBD.

Importantly, patients who were diagnosed with IBD, before or after their LC/CC diagnosis, showed more frequent signs of active inflammation.

“In conclusion, our study found that LC/CC can occur either before or after onset of IBD,” the researchers wrote. “IBD patients with initial presentation of LC/CC tend to occur in older age, with shorter interval time and frequent active inflammation in initial LC/CC. These findings suggest that LC/CC may be a spectrum of IBD as the initial presentation.”

“Even though LC/CC occurring either before or after the onset of IBD is a rare event among IBD population, it is still important for clinicians and pathologists to realize this disease pattern to avoid confusion and inadequate management,” they concluded.