Transcript Document

HIRSCHSPRUNG'S DISEASE
congenital megacolon
•Hirschsprung’s disease is the most common cause of lower
intestinal obstruction in neonates.
•Hirschsprung’s disease (aganglionic megacolon) is a
congenital anomaly caused by migratory failure of neural
crest cells leading to abnormal innervations of the bowel.
•The defect begins in the internal anal sphincter and extends
proximally for a variable length of gut.
Incidence & Etiology
• INCIDENCE: 1\5000 live birth newborn
• 70-80% is boys. (M / F. 4: 1 )
• Less common in blacks.
PATHOPHYSIOLOGY
EMBRYOLOGY:
– The neuroenteric ganglion cells migrate from the neural crest to the
upper end of the alimentary tract and then follow the vagal fibers
caudally
– delay or arrest in this migration results in the neural crest cells failing to
reach the distal bowel
PATHOPHYSIOLOGY
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The fundamental pathology in HD is the absence of ganglion cells in the submucosal and intermuscular nerve
plexuses and is associated with an increase in the nerve fibers in the affected segment .
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That aganglionic segment usually involves the terminal intestine, i.e. the rectum or rectosigmoid. The aganglionic
segment may, however, include the entire large bowel and even small bowel.
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The gross pathologic feature of HD is a dilated proximal intestine with gradual or abrupt transition to normal
calibrated distal intestine . The TZ is typically funnel like or cone shaped .
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The colon proximal to the aganglionic segment, in an effort to overcome the partial obstruction, becomes
distended and its wall markedly thickened because of muscle hypertrophy
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The degree of hypertrophy and dilatation depends upon the duration and degree of obstruction and thus, indirectly
to the age of the patient.
TYPES.
1.
Congenital : This type is the commonest one .
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2.
Etiology of the disease is still unknown.but Genetic factors are now
identified.
%10 of cases have familial history, especially those with long
segment disease.
Acquired :
Degeneration of the ganglions may occur due to:
-Vascular causes like after pullthrough procedure due to
ischemia & tension.
- Non vascular causes like
Trypanosoma (chaga's disease).
Vit B1 def.
Chronic infection ( TB.).
ASSOCIATED ANOMALIES
– HD is usually a solitary anomaly in a full term, otherwise healthy infant
– Associated anomalies do occur in nearly 20% of cases
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urogenital system (11%)
cardiovascular system (6%)
gastrointestinal system (6%),
with 8% having various other malformations
– Prematurity is reported in as many as 10% of those children with HD
– Trisomy 21 occurs in approximately 5% of cases
CLINICAL PRESENTATIONS :
1.
Failure to pass meconium in the 1st 24h of life
98% of neonates pass meconium in the first 24 hours of age.. Any newborn who
fails to pass meconium in the first 24-48 hours of life should be evaluated for
possible Hirschsprung's disease.
2.
Neonatal Intestinal obstruction
symptoms include bilious vomiting, abdominal distension and refusal to feed.
3.
Recurrent Enterocolitis mainly in the 1st three months of life.
4.
TOXIC MEGACOLON :
Fever.
Bile stained vomitous.
Dehydration.
5.
Abdominal distension.
Explosive diarrhoea.
Shock.
Spontanous perforation
occurs in 3%,specially if long segment
aganglionosis.
6.
Chronic constipation patients may have chronic
constipation in response to changes in feeding. And may
have Growth retardation. Multiple fecal masses on abdominal
examination.
Diagnosis
History
failure to pass meconium, painless abdomenal distension & constipation)
Physical examinations
Distended abdomen with Multiple fecal masses on abdominal examination
on DREcharacteristically there is
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Anal sphincter is hypertonic
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Rectum is typically empty.
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Hard fecal mass.
Radiology
1. Plain x-rays of the abdomen :Erect & supine
2. Contrast Enema.
Shows narrow distal segment,funnel-shaped dilatation at level of transition zone with
marked dilatation of the proximal colon.
24-hrs delayed films is important in diagnosis; it shows poor emptying with barium
throughout the colon, as opposed to the child with psychogenic stool holding in
whom the barium generally collects in the distal rectosigmoid.
contrast enema should be done with out preparation of bowel,
4. Electromanometry :
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not useful in neonate
excellent screening tool in infant & children .
The classic finding is the absence of the recto anal inhibitory
reflex when the rectum is distended.
5. Rectal biopsy :
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Rectal biopsy is the definitive diagnostic test and demonstrates
absence of ganglion cells, nerve hypertrophy and stains indicating
increased acetylcholinesterase activity.
suction mucosal biopsy (at different levels ). Can be done without
anesthesia
full thickness biopsy is done under general anesthesia.
6. UltraSonography: for associated anomalies.
Management :
Manegement of HD differs accosrding to the presentation form and clinical
situation of the patients:
• Acute I.O. : if the patient presents with acute intestinal obstruction in the
early life the management will be
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resuscitation ,
NGT , NPO
IVF ,
Antibiotics ,
Rectal tube,irrigations .
The initial treatment requires performing a "leveling" colostomy in the most distal
colon with ganglion cells present. This requires exploration with multiple
seromuscular biopsies of the colon wall to determine the exact extend of the
aganglionosis. The colostomy is placed above the transition zone. Placement of
the colostomy in an area of aganglionosis will lead to persistent obstruction
– When the patient becomes stable, then the definitive treatment will be planned.
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Chronic constipation :
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laxative
saline enema.
Work up to establish the diagnosis
then the definitive treatment will be planned
Definitive procedures:
Once the child has reached an adequate size and age (6-12 months; 20 pounds or more),
a formal pull-through procedure is done
1. Open surgery :
There are many surgical options for Pull-through operation. All aiming at
resection of aganglionic segment and anastomosing the two normal
ganglionic ends. They give excellent result in 90%.
a.swenson.
b.soave.
c.Rehbein.
d. Duhamel.
e. Boley's.
2.
3.
LAPAROSCOPY .
TEPT transanal endorectal pullthrough (without laparotomy )
COMPLICATIONS of Pullthrough
1.
2.
3.
4.
5.
anastomotic leak.
stricture .
retraction of the colon.
fecal incontinence (soiling or encopresis ).
persistant constipation.
Distinguishing features between childhood functional
constipation and Hirschsprung’s disease
Feature
Functional Constipation
Hirschsprung’s Disease
Onset
2-3 years
At birth
Delayed passage of meconium
Rare
Common
Obstructive symptoms
Rare
Common
Withholding behavior
Common
Rare
Fear of defecation
Common
Rare
Fear of incontinence
Common
Rare
Stool size
Very large
Small, ribbon-like
Poor growth
Rare
Common
Enterocolitis
Never
Possible
Rectal ampulla
Enlarged
Narrowed
Stool in ampulla
Common
Rare
Barium enema
Lg amount of stools,
no transitional zone
Transitional zone, delayed
emptying
Anorectal manometry
Normal
Absent rectosphincteric refl ex
Rectal biopsy
Normal
No ganglion cells, nerve hypertrophy
and increase acetylcholinesterase
activity
Back
Fig. 1 Plain X-ray showing dilated loops of bowel with absence of gas in the rectum
back
TZ
Back
Fig. 2 Contrast Enema showing Aganglionic segment with the transition zone
back