Hello and welcome to the Zero to Finals podcast. My name is Tom and in this episode I'm going

to be talking to you about Hirshsprungs disease. And if you want to follow along with written

notes on this topic, you can follow along at zero definals.com slash Hirshsprings or in the

gastroenterology section of the zero de finals pediatrics book.

So let's get straight into it.

Hirshsprings disease is a congenital condition where the nerve cells of the myenteric

plexus are absent in the distal bowel and rectum.

The myenteric plexus, which is also known as hourbax plexus, forms the enteric nervous system.

It's the brain of the gut. This nerve plexus runs all the way along the bowel in the bowel wall

and is a complex web of neurons, ganglion cells, receptors, synapses and neurotransmitters, and it's responsible

for stimulating peristosis of the large bowel.

Without this stimulation, the bowel loses its motility and stops being able to pass food along

its length.

The key pathophysiology in Hirschsprings disease is the absence of the parasympathetic ganglion cells.

During fetal development, these cells start higher up in the gastroenterrestrial tract

and migrate gradually down to the distal colon and the rectum.

Hirshsprings 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 parasympathetic

ganglion cells. The length of the colon without innovation varies between patients from a small

area to the entire colon.

When the entire colon is affected, this is called total colonic aganglionosis.

The aganglionic section of the colon does not relax, causing it to become constricted,

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