What is a small bowel obstruction?

The small bowel (small intestine) begins at the end of the stomach and continues for 21 feet in most adults until the colon (or large intestine) begins. A small bowel obstruction is a blockage of the small intestine.

Sometimes the bowels can become trapped outside of the abdominal cavity within surrounding tissues. If blood flow to the obstructed part of the bowel is cut off (strangulation) and the bowel wall begins to die, the obstruction can be life-threatening. Strangulation makes up about only one fourth to one third of the cases of small bowel obstruction.

How does it occur?

The major cause of small bowel obstruction is postoperative adhesions: bands of scar tissue that grow across sections of the bowel, trapping portions. Other causes include:

• hernia (weakness in the abdominal wall through which the intestines protrude)

• inflammatory bowel disease

• the intestine folding into itself, forming a cuff and cutting off normal flow of partly digested material (intussusception), and eventually cutting off blood flow to the tissues

• volvulus (twisted or knotted bowel)

• congenital narrowing of bowel

• ischemia (lack of oxygen flow to the bowel, when part of the bowel dies)

• cancer.

What are the symptoms?

The symptoms of a small bowel obstruction include:

• tender and enlarged abdomen

• cramplike abdominal pain

• vomiting

• low-grade fever

• failure to pass gas or stools

• dehydration (loss of water from the body): flushed dry skin, coated tongue, weakness, and confusion.

How is it diagnosed?

To diagnose a small bowel obstruction, your doctor will review your symptoms, examine you, and take a history of your previous operations, previous obstructions, and hernias. The doctor may order the following tests:

• blood tests

• chest x-ray and x-rays of the abdomen

• x-rays of the bowel after a barium enema

• endoscopy or colonoscopy.

How is it treated?

If your small bowel is partly obstructed, the treatment is usually decompression. This is done by decreasing the pressure of bowel gas with a nasogastric tube or other special tubing. Your doctor may prescribe antibiotics.

You may need to receive intravenous (IV) fluids to replace fluids and electrolytes you have lost and to prevent further dehydration.

Your doctor may need to perform surgery if your small bowel is completely obstructed. The decision to operate is based on the following:

• leukocytosis (too many white blood cells), indicating an infection

• strangulation (caused by not enough blood going to the affected area of the intestines)

• worsening symptoms

• abdominal tenderness

• blood in the stool

• air under the diaphragm, which means a perforation (hole in the wall) of the abdomen

• peritonitis (infection in the lining of the abdomen).

If your doctor decides to perform surgery, called a laparotomy, he or she will make a cut through the abdominal wall and then relieve the obstruction. It may be necessary to remove a portion of bowel, especially if the bowel has been strangulated or ischemic. Antibiotics are often prescribed if there is infection.

How long will the effects last?

How long the effects of a small bowel obstruction last depends on what caused the obstruction and whether the bowel has been strangulated. A strangulated bowel can be life- threatening. A long observation period after this surgery can usually be avoided by getting up and walking as soon after surgery as is reasonable.

How can I avoid small bowel obstruction?

Some people believe a high-fiber, low-fat, low-cholesterol diet reduces the chances of obstruction. You should increase your fiber gradually because sudden increases have actually caused obstruction. Have any hernias that may cause problems repaired in a timely fashion.