Hirschsprung's Disease

Question 1

What is Hirschsprung’s Disease?

Answer 1

• A congenital condition where the nerve cells of the myenteric plexus are absent in the distal bowel and rectum
• The myenteric plexus forms the enteric nervous system

Question 2

What is the Myenteric Plexus?

Answer 2

• The nerve plexus runs all the way along the bowel in the bowel wall
• It contains neurones, ganglion cells, receptors, synapses and neurotransmitters
• It is responsible for stimulating peristalsis of the large bowel.
• Without this stimulation the bowel looses it’s motility and stops being able to pass food along it’s length

Question 3

What is the key pathophysiology in Hirschsprung’s disease?

Answer 3

• Absence of Parasympathetic ganglion cells
• In fetal development these cells start higher in the GI tract and gradually migrate down to the distal colon and rectum.
• Hirschsprung’s disease occurs when the parasympathetic ganglion cells do not travel all the way down the colon and a section of colon at the end is left without these cells
• The aganglionic section of the colon does not relax causing it to become constricted, this leads to loss of movement of the faeces and obstruction in the bowel.
• Proximal to the obstruction the bowel becomes distended and full

Question 4

What length of colon is without innervation?

Answer 4

• This varies between patients from a small area to the entire colon
• When the entire colon is affected this is known as total colonic aganglionosis

Question 5

What are the Risk Factors for Hirschsprung’s Disease?

Answer 5

• Family History of Hirschsprung’s Disease
• Related to: Downs, Neurofibromatosis, MEN type 2

Question 6

What is the presentation of Hirschsprung’s Disease?

Answer 6

• Delay in passing meconium
• Chronic constipation
• Abdo pain and distention
• Vomiting
• Poor weight gain and failure to thrive

Question 7

What is Hirschsprung- Associated Enterocolitis?

Answer 7

• Inflammation and obstruction of the intestine
• Presents within 2-4 weeks of birth with fever, abdo distention, diarrhoea and features of sepsis
• life threatening and can lead to toxic megacolon and perforation of the bowel.
• Requires Abx, Fluid Resus and Decompression of the obstructed bowel

Question 8

What is the managment for Hirschsprung’s Disease?

Answer 8

• Abdominal Xray = helpful in diagnosing intestinal obstruction
• Rectal biopsy = bowel histology demonstrates an absence of ganglionic cells
• Fluid Resus and management of the intestinal obstruction. IV Abx are required
• Definitive management = surgical removal of the aganglionic section of bowel, may lead to temporary disturbances in bowel function and some degree of incontinence