The colon in patients with ankylosing spondylitis and in normal controls in Bangladesh: a macroscopic and microscopic study.

The objective of this paper is to study the macroscopic and microscopic aspects of colonic mucosa in patients with ankylosing spondylitis (AS) and in controls without colonic symptoms in Bangladesh. This observational study was done in a tertiary care center of Dhaka. Twenty-eight consecutive cases of AS were included, fulfilling modified New York Criteria with pure axial form or combined axial and peripheral joint involvement. Ten controls were enrolled in the study from people in whom endoscopy of upper gastrointestinal tract (GI) tract was performed and who had no musculoskeletal complaints and no colonic symptoms. Short colonoscopy (up to 60 cm) and colonoscopic biopsy were done in all. Histological features were evaluated following Cuvelier grading and Rubio and Kock scoring system. Demographic data including age and sex were similar in the AS and control groups. Out of 28 patients, ten had axial and 18 combined axial and peripheral joint disease, mostly pauciarticular. In the AS group, macroscopic and microscopic lesions were found in four and 14 subjects, respectively. Out of 22 subjects without diarrhea, seven had stage II and two had stage I changes. Six subjects in the AS group gave a history of diarrhea, of them three had stage I and two had stage II changes. In the control group, no macroscopic abnormalities were found. On histological examination, the mean diameter of transversely cut rectal glands, interglandular linear distances, number of glands per area, and total digital scores varied between 45-90 microm, 4.6-27 microm, 5-25, and 17-18 respectively. In eight of the ten controls, eosinophilic infiltration was found. Subclinical inflammatory lesions in the colonic mucosa are common in patients with ankylosing spondylitis. Colonic mucosa in normal individuals does not differ from that found in western studies, except for the presence of frequent mild eosinophilic infiltration in the lamina propria.