Intestinal Obstruction I: Introduction

Intestinal obstruction is a partial or complete blockage of the small or large intestine that disrupts the normal flow of intestinal content through the intestinal lumen.

It is classified by cause as mechanical or functional. Mechanical obstruction results from a physical blockage.

For example, adhesions are bands of fibrous connective tissue that form between normally separate anatomical surfaces. These bands can tether loops of bowel to each other, to the peritoneum, or to adjacent organs, predisposing them to intestinal obstruction.

A hernia is the protrusion of an organ or tissue, most often a portion of the intestine or omentum, through a weakness or defect in the containing wall of the cavity, commonly the abdominal wall.

Intussusception involves one segment of the intestine sliding into another adjacent segment, which can develop anywhere in the intestine.

Volvulus involves a loop of the small or large intestine twisting around itself, cutting off the flow of digestive contents.

On the other hand, functional obstruction, or paralytic ileus, is a temporary loss of intestinal motility. It most often develops after abdominal surgery, or may result from medications such as opioids, or bowel ischemia.