Congenital aganglionic Megacolon
By Dr Mohammad Manzoor Mashwani
Congenital Aganglionic Megacolon
• Hirschsprung disease is a developmental disorder
of the enteric nervous system and involves an
enlargement of the colon, caused by bowel
obstruction resulting from an aganglionic section
of bowel that starts at the anus & progresses
Harald Hirschsprung, Danish Physician 1886
• Two pathogenetic mechanisms have been
proposed for Hirschsprung's disease
• (1) failure of migration of neuroblasts to the distal
intestine ( rectum).
• (2) alteration of the colonic microenvironment
• Genetic, vascular, and infectious factors are
invoked to explain these alterations . Normal
migration may occur with a failure of neuroblasts
to survive, proliferate or differentiate in the distal
• Rate of occurrence 1 case per 5000 live births.
• Race - no racial predilection.
• Sex – M: F = 4:1. Long S.D F
• Age: Full term baby, uncommon in premature baby,
Can occur in adult life.
Hirschprung’s Disease, diagrammatic
representation of the pathologic changes
Gross specimen of Hirschprung’s Disease. The proximally
dilated segment of bowel has been resected.
Depending on the extent and location of the aganglionic segment, several forms of the
disease have been recognized:
Classic form. The aganglionic segment begins in the distal
colorectum and extends for a considerable distance in the adjoining
proximal dilated bowel.
2 Short-segment form. The aganglionic segment involves the
rectum and rectosigmoid for a distance of only a few centimeters.
3 Ultra-short segment form. In this variant, the aganglionic
segment is so short that the diagnosis can be missed if the biopsy is
taken too high.
4 Long-segment form (total colonic aganglionosis). Here the
abnormality is more extensive, involving most or all of the large
bowel, and occasionally extending even to the small bowel. These
patients present with symptoms of intestinal obstruction without
5 Zonal colonic aganglionosis. Only a short segment of bowel is
involved. In contrast to all other forms, ganglion cells are present not
only above but also below the aganglionic segment.
• Microscopically, the hallmark of the disease is the
absence of ganglion cells (aganglionosis) in both
plexuses of a segment of bowel.
Colonic mucosa stained for acetylcholinesterase from
a patient with Hirschsprung disease. There is a
marked increase in the number of nerve fibers in the
1) Delayed passage of meconium
2) Abdominal distension
Suspect Hirschsprung's in a baby who has not passed
meconium within 48 hours of delivery.
Recall that 90% of babies pass their first meconium
within 24 hours, and the next 9% within 48 hours.
Definitive diagnosis is made by biopsy of the
distally narrowed segment. Abdominal x-ray ( Plain) x-ray)
Barium Enema (Contrast
1. Full thickness biopsy
2. Suction biopsy
section of the
colon, followed by
Initial therapy should include
intravenous hydration, withholding
of enteral intake, and intestinal and
Decompression can be
accomplished through placement
of a nasogastric tube and either
digital rectal examination or normal
saline rectal irrigations 3-4 times
antibiotics to patients with
“Your practice of medicine
will be as good
as your understanding of
Sir William Osler.