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
[{'content': 'True about Hirschprung&;s disease \nSelect and explain. \nA. Aganglionic segment is contracted not dilated, B. Descending colon is most common site of aganglionosis, C. Barium enema is diagnostic, D. It is seen in infants & children only', 'role': 'user'}, {'content': "Answer: A \nExplanation: .It is a congenital, familial condition, occurring in newborn due to the absence of ganglion cells-- Auerbach's and Meissner's plexus in anorectum, which may extend proximally either a pa or full length of the colon. * It always involves the anus, internal sphincter and rectum (paly or entirely). * There is narrow, spasmodic, non relaxing pathological segment. * Transitional zone proximal to it contains only few ganglion cells with formation of cone. * Still proximal to it, colon is dilated enormously with hyperaemia, multiple ulcers and hyperophied circular muscle fibers. * It is one of the causes of neonatal intestinal obstruction. * Severe enterocolitis can occur which may be fatal. Perforation, peritonitis and septicaemia can occur. * Often there will be a chronic course of the disease with malnutrition, abdominal distension. ref:SRB&;s manual of surgery,ed 3,pg no 818", 'role': 'assistant'}]