[Application of chromoendoscopy to evaluate the severity and interobserver variation in chronic non-specific ulcerative colitis].

BACKGROUND: Ulcerative colitis (UC) is a disease of unknown etiology characterized by chronic and superficial inflammation of colorectum. Chromoendoscopy has been informed as a method to improve evaluation of extension of UC. No reports on this issue have been published in Mexico to date.

OBJECTIVE: To investigate usefulness of chromoendoscopy in determination of extension and severity of UC, as well as inter-observer variability.

PATIENTS AND METHODS: Twenty five patients with diagnosis of UC were selected from March 2001 to January 2002 to enter this prospective study. Baron scale was used to evaluate UC endoscopic severity and was followed by randomization of patients to receive methylene blue 0.2% (14 cases) or indigo carmine 0.1% (11 cases) for chromoendoscopic assessment. Each case was presented for evaluation to five endoscopists with > 5 years experience in colonoscopy. Histopathologic report was considered gold standard.

STATISTICAL ANALYSIS: Weighed Kappa coefficient for endoscopic-pathologic agreement among evaluators was used.

RESULTS AND DISCUSSION: There was fair agreement among endoscopic and pathologic diagnoses of each observer with the two tinctures, particularly when using indigo carmine. Chromoendoscopy increased detection of areas affected by UC with minimal or silent activity.

CONCLUSIONS: Chromoendoscopy with indigo carmine or methylene blue may increase endoscopic-pathologic agreement for assessment of severity of UC, thus being a helpful complementary technique in these patients.