Hirschsprung’s Disease Flashcards
What is Hirschsprung’s disease?
It is defined as a congenital condition in which the nerve cells of the myenteric plexus are absent in the distal bowel and rectum
Which bowel region tends to be affected by Hirschsprung’s disease?
It tends to be limited to the rectosigmoid segment, however, may extend proximally beyond the sigmoid colon
What is another term for the myenteric plexus?
Auerbach’s Plexus
What is the myenteric plexus?
It is a complex web of neurones, ganglion cells, receptors, synapses and neurotransmitters - which runs all the way along the bowel wall
What is the function of the myenteric plexus?
It forms the enteric nervous system, which is involved in peristalsis stimulation of the large bowel
What is the pathophysiological cause of Hirschsprung’s disease?
There is disrupted craniocaudal migration of neural crest cells during the first trimester of pregnancy
Therefore, they fail to reach the distal gut and subsequently differentiate into enteric ganglion cells
What is the pathophysiological consequence of Hirschsprung’s disease?
The lack of enteric innervation leads to tonic contraction of the aganglionic segment, resulting in lack of effective peristalsis and failure of the internal anal sphincter to relax
Ultimately, there is functional colonic obstruction, in which intestinal contents accumulate and subsequently result in secondary dilation of the proximal healthy innervated colonic tissue
What are the six risk factors associated with Hirschsprung’s disease?
Male Gender
Family History
Down’s Syndrome
Waardenburg Syndrome
Neurofibromatosis
Multiple Endocrine Neoplasia Type
What are the thirteen clinical features of Hirschsprung’s disease?
Failure To Thrive
Feeding Difficulties
Meconium Ileus
Bilious Vomiting
Chronic Constipation
Abdominal Distension
Abdominal Pain
Left Lower Quadrant Mass
Tympanic Percussion
Increased Bowel Sounds
Increased Anal Sphincter Tone
Empty Rectal Vault
Blast Sign
What is meconium?
It is the first stool a baby passes, which is usually black
How quickly after birth should meconium be passed?
Within 24 hours
What is meconium ileum?
It is defined as intestinal obstruction in the newborn, resulting in failure to pass meconium
What are the three clinical features of meconium ileum?
Meconium Absence Within 24 Hours
Abdominal Distension
Vomiting
What is the blast sign?
It occurs when withdrawal of the examining finger during digital rectal examination, leads to a gush of liquid stools and flatus
This is due to dramatic rectal decompression
What three investigations are used to diagnose Hirschsprung’s disease?
Abdominal X-Rays
Barium Studies
Rectal Biopsy
