This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
Toxic megacolon is seen in 
Select and explain. 
A. Chronic non specific ulcerative colities, B. Crohn's disease, C. Colonic diveiculosis, D. Hamaomatous polyp
A: Chronic non specific ulcerative colities
Answer: A: Chronic non specific ulcerative colities 
Explanation: .Toxic megacolon * 1.5% incidence * Common in transverse colon * Colon is more than 6 cm in diameter * Colon is like wet blotting paper * Commonly seen in ulcerative colitis * Can occur in bacterial colitis, pseudomembranous colitis, fulminant amoebic colitis * May be precipitated by antidiarrhoeal drugs * Emergency surgery, colectomy, colostomy/ileostomy may be required * IV fluids, blood transfusion, antibiotics, steroids are also needed * Can be life threatening* Plain X-ray is very useful. ref:SRB's manual of surgery,ed 5,pg no 895