A mechanical bowel obstruction is a partial or complete blockage in the intestine, which is also called the bowel. Blockages can occur at any point along the small or large bowel. They are more common in the small bowel. When the bowel is blocked, food and liquid cannot pass through. Over time, food, liquid, and gas build up in the area above the blockage. This can cause abdominal pain and swelling.

Causes

Most small bowel blockages are due to adhesions. An adhesion is a band of scar tissue that causes the bowel to attach to the abdominal wall or other organs. Most large bowel obstructions are caused by tumors.

Specific causes of bowel obstructions include:

• Hernia

• Tumors

• Bowel inflammation or swelling

• Foreign matter in the intestines

• Gallstones

• Impacted feces

• Volvulus (twisting of the intestine)

• Intussusception (telescoping of the intestine into itself)

• Scar tissue from a previous abdominal or pelvic surgery, particularly gynecologic or gastrointestinal operations

Risk Factors

A risk factor is something that increases your chances of getting a disease or condition. Risk factors for a bowel obstruction include anything that is likely to cause scar tissue or a blockage, such as:

• History of ulcers

• Previous gastrointestinal or gynecologic surgery

• Diverticulitis

• Crohn’s disease

• Hirschsprung’s disease (in infants and children)

• Cancer of the gastrointestinal tract

Symptoms

Symptoms of a bowel obstruction include:

• Abdominal pain

• Abdominal distention

• Abdominal cramps

• Nausea

• Vomiting

• Diarrhea

• Severe constipation; inability to pass gas or stool

• Bloating

• Fever

• Rapid pulse

• Foul breath odor

Complications from an untreated obstruction can include strangulation, which is cutting off of the blood supply to part of the intestine.

Diagnosis

Your doctor will ask about your symptoms and medical history and perform a physical exam. Your doctor will place a stethoscope on your abdomen to listen for bowel sounds; if the normal bowel sounds are absent, or if high pitched, tinkling sounds are present, it may be an indication of bowel obstruction. Further testing may include:

• Blood tests

• Urine tests

• Abdominal x-rays

• • Barium enema – injection of fluid into the rectum that makes your colon show up on an x-ray so the doctor can see abnormal spots

• • Endoscopy – insertion of a thin, lighted tube through the rectum to examine the intestine

• • CT scan of the abdomen

Treatment

Bowel obstructions can be serious, even fatal. If your doctor thinks you may have a bowel obstruction, you will be hospitalized and treated. Your treatment will depend on what part of your bowel is blocked and what is causing the blockage.

Possible treatments include the following:

Naso-gastric tube – the passage of a narrow tube through your nose and down into the stomach to suction out fluids that have become trapped above the blockage

Intravenous (IV) fluids – vomiting and diarrhea can cause dehydration and imbalances in your body fluids; if you are dehydrated, you will be given fluids and electrolytes (potassium and sodium) through a needle into one of your veins

Medications – you may be given antibiotics or pain medication through an IV or through the naso-gastric tube

Removal of fecal impaction – if fecal matter is causing the obstruction, it can be removed; your doctor will insert a gloved finger into your rectum to loosen and remove the feces

Endoscopy – a thin, lighted tube is inserted through the rectum and into the large intestine to straighten out the intestines

Surgery – depending on the cause of the obstruction, you may need surgery; surgery can:

• Remove scar tissue, tumors, gallstones, foreign matter, and other causes of the blockages

• Repair hernias

During surgery, the blocked part of the bowel may be removed. The remaining sections will then be joined together. You will probably need a naso-gastric tube temporarily after surgery. In addition, you may need antibiotics and pain medication during recovery.

Prevention

Prevention of bowel obstruction depends on the cause. Some bowel obstructions cannot be prevented. The following actions may help reduce your risk of a bowel obstruction:

• Treat hernias promptly before they can cause a blockage

• To lessen the chance of fecal impaction and diverticulitis:

• • Eat plenty of fiber-rich foods

• • Drink enough fluids, at least 8–10 glasses per day

• • Exercise regularly

RESOURCES:

American College of Gastroenterology
http://www.acg.gi.org

National Institute of Diabetes & Digestive & Kidney Disorders
http://www.niddk.nih.gov

References:

The Merck Manual of Diagnosis and Therapy, 17th ed. Simon and Schuster;1999.