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 bowel obstruction.

And you can find written notes on this topic at zero to finals.com slash surgery

or in the general surgery section of the zero to finals surgery book. So let's jump straight in.

A bowel obstruction refers to when the passage of food, fluid and gas through the intestines

becomes blocked. Small bowel obstruction is more common than large bowel obstruction. Obstruction results in a

build-up of gas and fecal matter proximal to the obstruction before the obstruction. This causes back

pressure resulting in vomiting and dilation of the intestines proximal to the obstruction.

Foul obstruction is a surgical emergency.

The gastrointestinal tracts accretes fluid that is later absorbed in the colon.

And when there's an obstruction, this fluid cannot reach the colon and it cannot be reabsorbed.

As a result, there is fluid loss from the intravascular space into the gastrointestinal tract. This leads to hypovalemia and shock, as the fluid that should

normally be in the body is actually lost into the bowel. This abnormal loss of fluid is

referred to as third spacing. The higher up the intestine

the obstruction is, the greater the fluid loss, as there is less bowel over which the fluid can

be reabsorbed. Let's talk about the causes. The big three causes that account for around 90%

of cases of bowel obstruction are adhesions,

which affect the small bowel, hernias, which typically affect the small bowel,

and tumours, which most often affect the large bowel.

Other causes include volvulus, which affects the large bowel, diverticular disease,

strictures, for example secondary to Crohn's disease, and interception, which affects young

children aged six months to two years. A tom tip for you, learn to recite the big three causes of obstruction without any hesitation.

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