Mechanical Bowel Obstruction

Definition

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.

Mechanical Bowel Obstruction

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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—when the intestine pulls inward into itself
• Scar tissue from a previous abdominal or pelvic surgery, particularly gynecologic or gastrointestinal operations

Risk Factors

Factors that increases your chance of getting 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 swelling
• Abdominal cramps
• Nausea
• Vomiting
• Diarrhea
• Severe constipation; inability to pass gas or stool
• Bloating
• Fever
• Foul breath odor

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

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. 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:

• Your bodily fluids may need to be tested. This can be done with:
  • Blood tests
  • Urine tests
• Images may need to be taken. This can be done with abdominal x-rays, such as:
  • Barium enema
  • Endoscopy
  • CT scan of the abdomen

Treatment

Bowel obstructions can be serious, even fatal. If your doctor thinks you 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:

• Nasogastric tube—This involves 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.
• 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.
• Medications—You may be given antibiotics or pain medication through an IV or through the nasogastric 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 nasogastric tube temporarily after surgery. In addition, you may need antibiotics and pain medication during recovery.

If you are diagnosed with a mechanical bowel obstruction, follow your doctor's instructions.

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 plenty of fluids.
  • Exercise regularly.