A 50 year old male known case of ulcerative colitis presents with distention of the abdomen of acute onset with vomiting. The next investigation would be

Answer- A. Abdominal X rayToxic megacolon is defined as a transverse colon with a diameter of more than 5.0 to 6.0 cm with loss ofhaustration.Although usually associated with ulcerative colitis, toxic megacolon can also be seen in Crohn's disease.Plain abdominal railiographs are essmtial for the iliagnosk and management of toxic megacolon (toxic colitis)