Hirschsprung Disease
Gastroenterology
aka congenital aganglionic megacolon (the mega is not affected!)
Neural crest cells migrate from cecum to the rectum
Premature arrest of this migration leads to agangliosis of the distal bowel from that point
Meissner submucosal and the Auerbach myenteric plexus are missing
causes bowel to fail to relax, leading to a functional obstruction
short segment = rectum +/- sigmoid
Long segment = beyond sigmoid
- TCA = total colonic agangliosis,
- rarely extends into small bowel
Presentation
Long segments
Distal obstruction
- vomiting: bilious
- distention
Failure to pass meconium >48hours (100% of neonates should pass a stool by 48hrs), (¾ of HS will fail to)
Enterocolitis
- fever, vomiting, diarrhoea, haematochezia
Squirt (aka blast) sign explosive expulsion of gas/stool on DRE
Short segments
- chronic constipation and failure to thrive
Complications
- volvulus
- toxic megacolon
Ix
indications
- no mec by 48 hours
- obstruction (bilious vomiting/distention)
- constipation + any of the known associations (below)
- constipation AND tight anal sphincter OR squirt sign
> Suction rectal biopsy
- 2 cm above the level of the dentate line (border of hind gut) (first 1 to 2 cm zone has normal physiologic aganglionosis)
- biopsy shows hypertrophied nerve bundles staining for ACe, without ganglions
(barium enema not as good, shows transition zone from dilated (backed up) normal bowel proximal to stenosis functionally obstructed affected bowel)
Associations
aka congenital aganglionic megacolon (the mega is not affected!)
Neural crest cells migrate from cecum to the rectum
Premature arrest of this migration leads to agangliosis of the distal bowel from that point
Meissner submucosal and the Auerbach myenteric plexus are missing
causes bowel to fail to relax, leading to a functional obstruction
short segment = rectum +/- sigmoid
Long segment = beyond sigmoid
- TCA = total colonic agangliosis,
- rarely extends into small bowel
Presentation
Long segments
Distal obstruction
- vomiting: bilious
- distention
Failure to pass meconium >48hours (100% of neonates should pass a stool by 48hrs), (¾ of HS will fail to)
Enterocolitis
- fever, vomiting, diarrhoea, haematochezia
Squirt (aka blast) sign explosive expulsion of gas/stool on DRE
Short segments
- chronic constipation and failure to thrive
Complications
- volvulus
- toxic megacolon
Ix
indications
- no mec by 48 hours
- obstruction (bilious vomiting/distention)
- constipation + any of the known associations (below)
- constipation AND tight anal sphincter OR squirt sign
> Suction rectal biopsy
- 2 cm above the level of the dentate line (border of hind gut) (first 1 to 2 cm zone has normal physiologic aganglionosis)
- biopsy shows hypertrophied nerve bundles staining for ACe, without ganglions
(barium enema not as good, shows transition zone from dilated (backed up) normal bowel proximal to stenosis functionally obstructed affected bowel)
Associations
- Trisomy 21
- Bardet-Biedl syndrome
- Cartilage-hair hypoplasia: short stature, short limbs with increased carrying angle at the elbow, increased lumbar lordosis, ligamentous laxity, scoliosis, and immunodeficiency
- Congenital central hypoventilation syndrome (CCHS) (Haddad syndrome
- Familial dysautonomia
- Multiple endocrine neoplasia type 2 (MEN2)
- Mowat-Wilson syndrome (MWS): distinctive facial characteristics, moderate to severe intellectual disability, genitourinary anomalies, and heart defects.
- Smith-Lemli-Opitz syndrome
- Waardenburg syndrome
- Genitourinary anomalies
- Visual and hearing impairment
- Congenital heart disease
- Anorectal malformations