<prompt> True about Hirschprungs disease :Aganglionic segment is contracted not dilatedDescending colon is most common site of aganglionosisBarium enema is diagnosticIt is seen in infants children only  <response>: Ans: A Aganglionic segment is contracted not dilated Hirschsprug Disease HD HD is characterised by the congenital absence of intramural ganglion celts aganglionosis the presence of hypertrophic nerves in the distal targe bowel. The aganglionosis is restricted to the rectum sigmoid cofon3 in 75 of patients short segment, involves the proximal colon in 15 long segment affects the entire colon a portion of terminal ileum in 10 total colonic aganglionosis A transition zone exists bw the dilated, proximal, normally innervatedbowel the narrow, distal aganglionic segment: HD typically presents in the neonatai period with delayed passage of meconium abdominal distensionq bilious vomiting but it may not be diagnosed until later in childhood or even adult life. Males are affected more often the females 4 : 1 HD may be associated with other congenital defects including Down - syndrome, Smith-Lemli-Opitz syndrome, Waardenburg syndrome, cartilage hair hypoplasia syndrome congenital hypoventilation Ondine curse syndromes urogenital or cardiovascular abnormalities. Gene mutation have been identified on chromosome 10 involving RET proto-oncogene on chromosome 13 in some patients. Breast fed infants may not suffer as severe the disease as formula fed infants.Diagnosis Rectal manometry: rectal suction biopsyQare the easiest most reliable indicators of HD Rectal suction biopsies a re the procedure of choicec should be performed no closer than 2cm to the dentate line to avoid the normal area of hypoganglionosis at the anal verge. Anorectal manometry measures the pressure of the internal anal sphincter while a balloon is distended in the rectum. In patient with HD, the pressure fails to drop or there is a paradoxical rise in pressure with rectal distension. Barium enema examination should be done in unprepared bowel as washouts may minimise the dilation of the gut above the obstruction. It is always essential that both AP lateral views should be taken as narrow short segments may be overlapped by dilated proximal colon in one of the views.Treatment Colostomy - Prompt colostomy should be performed in neonate with this disease Definitive operation is postponed till the child becomes at least 1 year of age of normal weight. It includes-Swensons operation, Duhamels operation, Sovaes operations , coloanat anastomosis etc. 