3. Definition
Hirschsprung disease ( HSCR) also called congenital aganglionic
megacolon,
is a disorder of the abdomen that occurs when part or all of the large
intestine or antecedent parts of the gastrointestinal tract have no
nerves and therefore cannot function. The major gene of
Hirschsprung disease was identified in this chromosomal 10 region,
it was the RET protooncogene .
1/5000 live births
M:F = 4:1
Racial distribution similar
4. There are four types of Hirschsprung disease:
In 80% of individuals, aganglionosis is restricted to the rectosigmoid colon
( short-segment disease).
In approximately 15%-20%, the aganglionosis extends proximal to the
sigmoid colon ( long-segment disease).
In approximately 5% of individuals, aganglionosis affects the entire large
intestine ( total colonic aganglionosis).
Rarely, the aganglionosis extends into the small bowel or even more
proximally to encompass the entire bowel ( total intestinal aganglionosis)
5. Embryology and Etiology
Neuroenteric cells migrate from neural crest to upper end
of alimentary tract and proceed in distal direction
12th week : migration to distal colon – first into myenteric
(Auerbach’s plexus) then into submucosal plexus
Embryologic defect
6. Failure of neural crest migration
Immunologic mechanism: increased expression of class II
antigens in the mucosa and submucosa-> causes fetus to
mount an immunologic response against the neuroblast
Genetic factors: May affect more than one family member
in 3-7% of cases
Deletion in the RET gene chromosome 10q11 and EDNRB
gene located on 13q22 and EDN 3 gene (major role in the
development of the enteric nervous system)
8. Pathology
Neonatal period: intestine is normal
Proximal ganglionic intestine hypertrophies and becomes thicker and
longer than normal
Taeniae disappear and longitudinal muscle layer completely surrounds
colon
Distal intestine: absence of ganglion cells in the submucosal (Meissner’s)
plexus and myenteric (Auerbach’s) plexus
Marked increase in nerve fibers which extend into the submucosa (seen
with acetylcholinesterase stain)
Aganglionosis extends to rectosigmoid region in 80% of cases
10. Presentation
Severe abdominal distention
95% - failure to pass meconium in first 24 hours life
Bilious vomiting
Older children - constipation, failure to thrive
10-15% - severe diarrhea alternating
constipation—enterocolitis of Hirschsprung’s disease
11. Symptoms
chronic constipation:
- Delayed passage of meconium > 24 hrs.
- Defecation occurs every few days & only after insertion of a finger of the mother
in the anus of the baby.
12. Signs
1. inspection:
- Abdominal distension, visible peristalsis.
2. Palpation:
- Doughy mass in Lt. iliac fossa.
3. Percussion:
- Tympanitic resonance.
4. Auscultation: increase intestinal sounds.
5. DRE:
- Empty rectum
- Grips on the finger.
- Characteristic gush of foetid stool on withdrawal of the fingers.
13. General:
1. Delayed growth and development.
2. Chest infection.
Local:
1. Obstructive toxic enterocolitis (fever,
diarrhea and abdominal distension) >>
cause of death.
2. Acute obstruction.
moderate cases: failure to thrive
17. Barium Enema
Less sensitive for detecting short lesions, total colon
aganglionosis, and disease of the newborn
Many newborns do NOT show definitive transition
zone
Delayed evacuation of contrast
21. Swenson Procedure
Sharp extrarectal dissection down to 2 cm above the anal
canal.
Aganglionic colonic segment resected End-to-end
anastamosis of normal proximal colon to anal canal
Completely removes defective aganglionic colon.
23. Duhamel Procedure
Posterior portion of defective colon segment resected
Side to side anastamosis to left over portion of rectum
Constipation a major problem remaining aganglionic tissue
Simpler operation, less dissection.
25. Soave Procedure
Circumferential cut through muscular coat of colon at
peritoneal reflection
Mucosa separated from the muscular coat down to the anal
canal
Proximal normal colon is pulled through retained muscular
sleeve
Telescoping anastamosis of normal colon to anal canal
