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 -

Ans. is 'a' i.e., Abdominal X-ray o It is a case of toxic megacolon.o Toxic megacolon is defined as a transverse colon with a diameter of more than 5.0 to 6.0 cm with loss of haustration. Although usually associated with ulcerative colitis, toxic megacolon can also be seen in Crohn's disease.Diagnosiso Plain abdominal radiographs are essential for the diagnosis and management of toxic megacolon (toxic colitis), or TM (TC). Repeated abdominal plain films are necessary to evaluate the efficacy and progress of treatment.o Radiographic findings include the following:o Dilated (>6 cm) transverse colono Presence of intraluminal soft-tissue masses (ie, pseudopolyps)o Free intraperitoneal air - Possible finding, best seen on upright chest radiograph or left lateral decubitus abdominal filmo Segmental parietal thinning is pathognomic for toxic megacolon# Most dangerous complication of toxic megacolon is Perforation.# Precipitating factors for toxic megacolon1) Opioid use2) Anticholinergic use3) Hypokalemia4) Barium enemas# T/T of Toxic megacolon : About 50% of acute dilatations will resolve with medical therapy alone, but urgent colectomy is required for those that do not improve.# Note: Toxic dilatation can also be rarely seen ino Crohn's diseaseo Amoebic colitiso Salmonellosis