True about Hirschprung's disease :

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 cofon'3 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 b/w 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-Swenson's operation, Duhamel's operation, Sovae's operations , coloanat anastomosis etc.