HIRSCHSPRUNG DISEASE
DEFINITION:
A congenital disorder caused by an abnormal innervation of the
bowel resulting in lower intestinal obstruction or chronic
constipation (also called Congenital Aganglionic Megacolon).
EPIDEMIOLOGY:
- incidence: 1/5,000-8,000 live births
- age of onset:
- soon after birth through childhood
- risk factors:
- familial - there may be an autosomal recessive form
- M > F (2-5:1)
- Whites > Blacks
- associated with other congenital defects:
- Trisomy 21
- Laurence-Moon-Bardet-Biedl Syndrome
- Smith-Lemli-Opitz Syndrome
- Waardenburg Syndrome
- others:
- renal agenesis, cryptorchidism, bladder malformations
- imperforate anus, Meckel's diverticulum, polyposis coli
- hydrocephalus
PATHOGENESIS:
- arrest of neuroblast migration from the proximal to distal
bowel -> absence of the intramural myenteric parasympathetic
nerve ganglia and sympathetic nerve plexus beginning in the
internal anal sphincter and extending proximally variable
distances from the anus -> aganglionic segment unable to relax
-> bowel wall hypertonicity -> inability of the affected bowel
to transmit peristaltic waves -> variable degrees of physiologic
intestinal obstruction -> fecal stasis -> proliferation of
bacteria -> toxic megacolon -> enterocolitis
- aganglionic segment:
- in 70-75% of cases, limited to the rectosigmoid
- in 15-20% of cases, involves variable lengths of the colon
- in 10% of cases, involves the entire colon
- in 1-10% of cases, involves the small bowel
- (84% of cases, involvement is distal to the splenic
flexure)
CLINICAL MANIFESTATIONS:
- delayed passage of meconium (more than 48 hours post
delivery)
- newborn constipation
- rectal exam:
- normal anal tone
- empty ampulla
- poor weight gain
2. Infants/Children
- chronic constipation with absence of fecal soiling
(usually from birth)
- difficulty controlling bowel movements
- abnormal history of bowel training
- intermittent vomiting
- large fecal mass on abdominal palpation
- stools: ribbon- or pellet-like, fluid consistency
- rectal exam:
- normal anal tone
- empty ampulla
- explosive evacuation of fecal fluid and gas on
withdrawal of finger from rectum
2. Complications
- intermittent or complete intestinal obstruction with
abdominal distention and bilious vomiting
- enterocolitis (C. difficile, S. aureus, anaerobes, coliforms)
with toxic megacolon, diarrhea, lethargy, fever, dehydration,
and/or sepsis
- failure to thrive +/- malnutrition
- protein-loosing enteropathy +/- hypoproteinemia, edema,
anasarca
- obstructive uropathy secondary to ureterovesical obstruction
- melena
INVESTIGATIONS:
- intestinal distention
- absence of normal rectal gas pattern
- retained barium 24 hours after a barium enema
- a transitional zone may not be present:
- before 1-2 weeks of age and may appear as a
funnel-shaped area
- when the entire colon is aganglionic
2. Barium Enema
- narrowed distal aganglionic segment
- dilated proximal ganglionic segment
- diagnostic in 81.5% of cases, suggestive in 14.6%, and
non-diagnostic in 3.9%
2. Pathology
- absence of submucosal and myenteric ganglion cells
- absence of Meissner and Auerbach plexus
- hypertrophied nerve bundles with high concentration of
acetylcholinesterase
- the aganglionic region may involve the transitional
segment
- normal distribution or proliferation of ganglion cells in
the region of the colon proximal to the transitional zone
3. Anorectal Manometry
- absence of the anorectal inhibitory reflex:
- with rectal distention, the internal anal sphincter
pressure fails to drop or there is a paradoxical rise in
pressure
MANAGEMENT:
- if evidence of intestinal obstruction place NPO, give IV
fluids, place an NG tube, and transfer to a tertiary care
hospital
2. Surgery
- various surgical options are available depending on the
extent of the aganglionic segment
- a temporary colostomy may be performed initially until the
normal colonic function is restored followed by a definitive
reanastomosis with a modified distal rectum and modified or
removed aganglionic segment
- a simple myotomy may be used in ultrashort segment
Hirschsprung Disease where the aganglionosis is limited to the
internal anal sphincter
3. Prognosis
- a majority of patients achieve fecal continence
- 10% occurrence risk in siblings of affected patients
- 20% occurrence risk in siblings of patients with total colon
aganglionosis
- normal life expectancy
ADDITIONAL REFERENCES:
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