Hi, this is Tom, and in this episode I'm going to be going through Hersprings

Disease, and you can find notes at zero to finals.com and in the zero to finals pediatrics book,

and you can find flashcards and questions at members.0 tofinals.com. And at the end of this episode, we'll go through some

questions so you can test yourself on what you just heard. So let's jump straight in.

Hurstprung's disease is a congenital condition where the ganglion cells of the enteric nervous

system are absent in a distal portion of the bowel,

most often the sigmoid colon and rectum. Let's start by talking about the pathophysiology.

The enteric nervous system, which is the brain of the gut, consists of two plexuses. The myenteric plexus, or

hourbax plexus, which primarily is responsible for peristalysis, and the submucosal plexus,

or mizenus plexus, which regulates fluid secretion, blood flow and absorption.

In Hirshbrung's disease, the ganglion cells of the myenteric plexus and the submucosal

plexus are absent. During fetal development, these cells start higher up in the gastrointestinal tract and gradually

migrate down to the distal colon and the rectum.

Hirshsprings occurs when the ganglion cells do not migrate all the way down the colon,

and a section is left without these cells.

The length of the colon without innovation varies between patients, from a small area of the

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

aganglionosis. The aganglionosis.

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

obstruction. The bowel that's higher up or more proximal than the affected section becomes dilated and overloaded.

Let's talk about the genetics and associations.

Many genes modify the risk of developing Hirshsprung's disease.

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