This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Which of the following can cause toxic megacolon in 36 year old lady? \nSelect and explain. \nA. Amoebic colitis, B. IBS, C. Ulcerative colitis, D. Viral diarrhea', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The hallmarks of toxic megacolon (toxic colitis), a potentially lethal condition, are nonobstructive colonic dilatation larger than 6cm and signs of systemic toxicity. The impoant etiologies of toxic megacolon include the following inflammatory causes: Ulcerative colitis Crohn colitis Pseudomembranous colitis The complication of toxic megacolon is perforation, even in the absence of colonic dilatation.', 'role': 'assistant'}]