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
What are the three features of Hirschsprung’s disease on abdominal x-ray scans?
Air-Fluid Levels
Distended Proximal Bowel Loops
Rectal Gas Absence
What are the two features of Hirschsprung’s disease on barium studies?
Transition Zone Between Contracted Distal Bowel & Dilated Proximal Bowel
Saw-Tooth Appearance of Aganglionic Segment
What is the gold standard investiation used to diagnose Hirschsprung’s disease?
Rectal biopsy, with acetylcholinesterase staining
When are rectal biopsies used to diagnose Hirschsprung’s disease?
It is indicated when individuals present with one or more of the following criteria…
- Hirschsprung’s Disease Family History
- Meconium Ileus > 48 Hours of Birth
- Neonatal Constipation
- Chronic Abdominal Distension & Vomiting
- Failure To Thrive & Any Other Above Features
What are the two features of Hirschsprung’s disease on rectal biopsies?
Colonic Ganglion Cell Absence
Hypertrophic Acetylcholinesterase-Positive Nerve Fibres In Distal Rectum > 40 Micrometres
What are the three immediate management options of Hirschsprung’s disease?
IV Fluid Resuscitation
Rectal Washouts
Bowel Irrigation
What is the defintive management option of Hirschsprung’s disease?
Surgical Resection
What is surgical resection?
It involves removal of the aganglionic bowel segment, followed by a pull-through of the proximal healthy bowel down to the anal canal with preservation of the sphincter function
What are the five complications associated with Hirschsprung’s disease?
Hirschsprung Associated Enterocolitis (HAEC)
Bowel Perforation
Enterocolitis
Faecal Incontinence
Urinary Incontinence
What is Hirschsprung Associated Enterocolitis (HAEC)?
It is defined as inflammation and obstruction of the intestine
What is the pathophysiological consequence of Hirschsprung’s disease?
It results in dysmotility, dysbiosis of the gut microbiome and defective intestinal barrier function/mucosal immune response
Ultimately, this can lead to toxic megacolon and bowel perforation
When does Hirschsprung-Associated Enterocolitis (HAEC) tend to present?
2 - 4 weeks of birth
What are the three clincial features of Hirschsprung-Associated Enterocolitis (HAEC)?
Fever > 38C
Bloody Diarrhoea
Abdominal Distension
What are the six immediate management options of Hirschsprung-Associated Enterocolitis (HAEC)?
IV Broad-Spectrum Antibiotics
IV Fluid Resuscitation
Nasogastric Tube Insertion
Nil By Mouth
Sepsis Six Care
Bowel Irrigation
