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': 'Not true regarding Hirschsprung disease is - \nSelect and explain. \nA. Autosomal dominant, B. Absent ganglionic cells in myentric plexus, C. Absent ganglionic cells in submucus plexus, D. Rectal biopsy is diagnostic', 'role': 'user'}, {'content': "Answer: A \nExplanation: Hirschprungs ds or Aganglionic megacolon or Congenital megacolon \n\nis a congenital disorder d/t absence of ganglion cells in the neural plexus ie both myenteric (Auerbach's) and submucosal (Meissner's) plexus of the intestinal wall.\nThere is accompanying hypertrophy of the nerve trunks.\nMC site is a rectosigmoid colon. (or Rectum, more specifically)\nThe Clinical picture varies from acute intestinal obstruction in neonates to chronic constipation in later life.\nOne imp feature which distinguishes Hirschprungs disease from other types of constipation is that faecal soiling is not a feature of HD.\nM: F ratio is 4: 1\n\nDiagnosis:\nBarium enema: The initial diagnostic step in a newborn with radiographic evidence of a distal bowel obstruction is a barium enema. In a normal barium enema study, the rectum is wider than the sigmoid colon. In patients with Hirschsprung's disease, this relationship is reversed.\nRectal biopsy -\nDiagnosis can be confirmed by a full thickness rectal biopsy. A rectal biopsy is a gold standard for the diagnosis of Hirschsprung's disease.\nThe histopathologic features of Hirschsprung's disease are:\nAbsent ganglia,\nhypertrophied nerve trunks, and\nincreased acetylcholinesterase staining\n\nAnorectal manometry -\nis a useful screening test in constipated young child or adult who is otherwise fit.\nTreatment of choice\n\nis a pull-through procedure in which normally innervated colon is anastomosed to the distal rectum just above the internal sphincter, thus bypassing the contracted aganglionic segment and restoring normal defecation.\n\nOption a\n\nMost of the cases are sporadic, Familial cases also occur but their inheritance pattern is not clear.", 'role': 'assistant'}]