S3394 A Case Report of Atypical Ulcerative Colitis

Abstract

INTRODUCTION: Ulcerative colitis(UC) and Crohns disease usually have specific presentation on colonoscopy with some overlap seen in select cases. UC predominantly involves colon, with almost always involving the rectum and rarely involving the ileum. However, in about 5% of the cases, IBD can present in atypical way labelled as “indeterminate” or “unclassified”. In these cases, UC can present with skip lesions with rectal sparing which can pose a diagnostic challenge if only visual diagnosis is focused upon. CASE DESCRIPTION/METHODS: 27 year old female presented to GI clinic with rectal pain and diarrhea for several months. On the rectal exam, there was pinhole like opening and ulceration. Outpatient colonoscopy was performed and revealed few skip lesions of erythematous, friable and ulcerated mucosa in the transverse colon and terminal ileum. The pathology showed mild acute, focal inflammation and crypt abscess in terminal ileum, transverse, descending and sigmoid colon. Rectal biopsy showed normal findings. The stool studies were sent and C diff test came positive. After the 2week course of oral vancomycin, symptoms were significantly improved. Subsequently, she was placed on Mesalamine. 8 months later, repeat colonoscopy revealed inflamed, erythematous, congested skip lesions at terminal ileum and transverse colon. UC was confirmed again with the presence of mild inflammation and cryptitis. DISCUSSION: Patients who have RST(rectal sparing of UC) represent resistance to treatment, prolong duration of active disease and increased rate of recurrence. It might be a prediction for future colectomy given the severity of the disease. Severity of the disease was significantly worse in patients with RST compared to the control group and 24/46 pts with RST required urgent surgery compared with 107/436 non RST group. These patients have also seen to have a lack of response to conventional pharmacotherapy. Frequency of PSC (primary sclerosing cholangitis) with and without rectal sparing is also studied. The reported incidence showed a mean(30.9% vs 9.9%) in PSC with rectal sparing, compared with the group without rectal sparing. Overall, incidence of PSC was 3 times higher in rectal sparing group. In conclusion, the presence of relative or absolute RST in patients with UC is an atypical presentation. This group of patients should be selectively reclassified due to worse prognosis with higher incidence rate of emergent surgery, primary sclerosing cholangitis and refractoriness of pharmacologist therapies.Figure 1.: Congested, erythematous, friable and inflamed terminal ileum.Figure 2.: Rectum with normal appearing mucosa.