Hirschsprung disease Flashcards
Define Hirschsprung disease.
A congenital condition characterised the absence of ganglion cells –> tonically contracted lumen –> partial or complete colonic functional obstruction.
The aganglionic portion of the colon is always located distally, but the length of the segment varies. This determines the varied manifestations of the disease.
When do patients with Hirschsprung disease present?
The vast majority of patients present in the newborn period up to 1 year of age. Diagnosis later in life occurs rarely.
What is the aetiology of Hirschsprung disease?
Congenital
deletion in the long arm of chromosome 10 (overlaps the RET proto-oncogene which is also associated with MEN2A)
- absence of ganglion cells,
- presence of hypertrophic nerves - absence of Meissner’s and Auerbach’s plexuses and hypertrophied parasympathetic ganglia.
- increase in the enzyme acetylcholinesterase,
= keys to pathological diagnosis
How common is Hirschsprung disease?
- ~1 in 5000 births (relatively common)
- White people
- M>F but Fhave more severe disease
What investigations would you do for Hirschsprung disease?
AXR - not diagnostic but shows distended colon in most cases so should be initially done
Contrast enema - may show transition zone
Rectal biopsy - definitive diagnosis by histological confirmation of absence of ganglion cells
Which congenital anomaly is associated with Hirschsprung disease?
~5%- 32% of all individuals affected have an associated congenital anomaly e.g. Down’s syndrome is common
What are the main clinical manifestations of Hirschsprung disease?
- Abdominal distension
- Delayed passage of meconium (not occurring in the first 24 to 48 hours of life)
- Vomiting
What happens when spontaneous passage of stool occurs?
- It is explosive, deflating with passage of liquid and gas,
- This dramatically improves the baby’s condition
- It is followed by a period of hours or days of a relative absence of symptoms followed by recurrence of the same manifestations
What is the effect of Hirschsprung disease on growth?
May cause failure to thrive
What should you suspect if you see fever in Hirschsprung disease?
Enterocolitis - from prolonged distension and faecal stasis
Sepsis - endotoxin related shock , hypovolaemia from moving fluid into bowel, bacterial overgrowth from stasis
Which reflex is absent in Hirschsprung disease?
Normally when the rectum is distended with a balloon, pressure in the anal canal falls due to internal sphincter relaxation. This reflex is absent in aganglionosis - can be tested by anorectal manometry (usually not necessary to test)
What is the management of Hirschsprung disease?
- Bowel irrigation*
- Surgery - usually in the first week of life or can return within 2-3 months of life
*In enterocolitis fluids and IV antibiotics should also be prescribed with bowel irrigation. Decompression may be required by colostomy or ileostomy.
Short-segment disease (<2cm) - laxatives (but there is debate of its existance)
What are the surgical options for Hirschsprung disease?
Surgical removal of the distal aganglionic segment with pull-through of the proximal normal ganglionic bowel
Ileostomy in those with total colonic aganglionosis. Usually closed once old enough to be toilet traines as acidic stool
Which part of the bowel is most commonly affected in Hirschsprung disease?
Rectum and much of the sigmoid colon (70%-80% of cases)
What is the prognosis/what are the complications of Hirschsprung’s disease?
Usually good prognosis although risk of enterocolitis within 1yr of surgery and risk of incontinence/abscess/diarrhoea after surgery
What are the differences in air pattern on x-ray in a proximal and distal obstruction?
Few dilated loops of bowel seen = proximal. Duodenal stenosis has a classic double bubble appearance on X-ray (right).
Multiple dilated loops of bowel in a patient who has not passed meconium = more distal obstruction
What is seen on this AXR?
Air under the diaphragm
Air around the liver
Dilated small bowel
