Intestinal Obstruction

What is this condition?

Intestinal obstruction is a partial or complete blockage of the small or large bowel. Small-bowel obstruction is far more common (90% of cases) and usually more serious because it progresses quickly. Complete blockage is a life-threatening condition that must be treated within hours. An obstruction is most likely to occur after abdominal surgery or in persons with congenital bowel deformities.

What causes it?

Bowel sections that grow together and pockets of trapped wastes usually cause small-bowel obstruction. Cancer is a major cause of large­bowel obstruction. Other causes are foreign bodies (fruit pits, gallstones, worms) or compression of the bowel wall due to stiffening, twisting, or tumors. Illness, infection, and nerve disorders can trigger an obstruction too.

Intestinal obstruction develops in three stages:

. simple - blockage prevents intestinal contents from passing, with no other complications

. strangulated - blood supply to part or all of the obstructed section is cut off, in addition to blockage of the tube

. close-looped - both ends of a bowel section are plugged, isolating it from the rest of the intestine.

In all three forms, fluid, air, and gas collect near the blockage.

Muscle action increases temporarily, as the bowel tries to force its contents through the obstruction, injuring the bowel lining and bulging the blocked section. The bulge blocks blood flow in the surrounding veins, stops the normal absorption of wastes, and forms a pool of water and salts. Because the body cant process food or liquid, the person becomes dehydrated and feels extremely ill.

What are its symptoms?

Colicky pain, nausea, vomiting, constipation, and abdominal bulging characterize small-bowel obstruction. It may also cause drowsiness, intense thirst, general discomfort, dry mouth, and aching. The doctor may be able to hear the agitated bowel, even without a stethoscope, and find tenderness when pushing on the abdomen. The higher the obstruction, the earlier and more severe the vomiting.

Symptoms of large-bowel obstruction develop more slowly, because the colon can absorb fluid from its contents and stretch well beyond its normal size. Constipation may be the only effect for days; then abdominal pain may appear suddenly, producing short spasms that occur every few minutes. Continuous pain and nausea may develop and bulges in the abdominal wall may be visible.

How is it diagnosed?

The doctor will ask about the person's abdominal pain and confirm the cause of any bulge with X-rays and lab tests.

How is it treated?

First, the doctor will correct the person's fluid and electrolyte imbalances with intravenous liquids. Then to relieve the abdominal pressure, a tube will be put down the person's throat to bring up the trapped material. The long, weighted tube usually works, especially in small-bowel obstruction.

If the tube isn't effective, surgery is necessary. In large-bowel obstruction, surgical removal of the damaged portion of intestine usually follows decompression with a tube. Then the person may need treatment for nutrition deficits or infection. Drug therapy includes analgesics, sedatives, and antibiotics.