Health Encyclopedia

Intestinal obstruction

Definition

Intestinal obstruction involves a partial or complete blockage of the bowel that results in the failure of the intestinal contents to pass through.

Alternative Names

Paralytic ileus; Intestinal volvulus; Bowel obstruction; Ileus; Pseudo-obstruction - intestinal

Causes, incidence, and risk factors

Obstruction of the bowel may be caused by ileus -- in which the bowel doesn't function correctly but there is no "mechanical" (anatomic) problem -- or by mechanical causes. Paralytic ileus, also called pseudo-obstruction, is one of the major causes of obstruction in infants and children.

The causes of paralytic ileus may include the following:

Medications, especially narcotics
Intraperitoneal infection
Mesenteric ischemia (decreased blood supply to the support structures in the abdomen)
Injury to the abdominal blood supply
Complications of intra-abdominal surgery
Kidney or thoracic disease
Metabolic disturbances (such as decreased potassium levels)

Paralytic ileus may lead to complications causing jaundice and electrolyte imbalances. In the newborn, paralytic ileus that is associated with destruction of the bowel wall (necrotizing enterocolitis) is life-threatening and may lead to infection in the infant's blood and lungs.

In older children, gastroenteritis may be a cause of paralytic ileus, which is sometimes associated with peritonitis and a ruptured appendix.

Paralytic ileus is marked by abdominal distention, absent bowel sounds (no noise heard when listening to abdomen), and abdominal pain.

Mechanical obstruction occurs when movement of material through the intestines is physically blocked. The mechanical causes of obstruction are numerous and may include the following:

Hernias
Postoperative adhesions or scar tissue
Impacted feces (stool)
Gallstones
Tumors blocking the intestines
Granulomatous processes (abnormal tissue growth)
Intussusception
Volvulus (twisted intestine)
Foreign bodies (ingested materials that obstruct the intestines)

If the obstruction blocks the blood supply to the intestine, the tissue may die, causing infection and gangrene. Risk factors for tissue death include intestinal malignancy, Crohn's disease, hernia, and previous abdominal surgery.

Symptoms

Abdominal fullness, gaseous
Abdominal distention
Abdominal pain and cramping
Vomiting
Failure to pass gas or stool (constipation)
Diarrhea
Breath odor

Signs and tests

While listening to the abdomen with a stethoscope your health care provider may hear high-pitched bowel sounds at the onset of mechanical obstruction. If the obstruction has persisted for too long or the bowel has been significantly damaged, bowel sounds decrease, eventually becoming silent.

Early paralytic ileus is marked by decreased or absent bowel sound.

Tests that show obstruction include:

Treatment

The objective of treatment is to decompress the intestine with suction, using a nasogastric (NG) tube inserted into the stomach or intestine. This will relieve abdominal distention and vomiting.

Surgery to relieve the obstruction may be necessary if decompression by NG tube does not relieve the symptoms, or if tissue death is suspected.

Expectations (prognosis)

The outcome varies with the cause of the obstruction.

Complications

Infection
Gangrene of the bowel
Perforation (hole) in the intestine

Calling your health care provider

Call your health care provider if persistent abdominal distention develops and you are unable to pass stool or gas, or if other symptoms of intestinal obstruction develop.

Prevention

Prevention depends on the cause. Treatment of conditions (such as tumors and hernias) that are related to obstruction may reduce the risk.

Some causes of obstruction are not preventable.

Review Date:4/12/2007
Reviewed By:A.D.A.M. Editorial Team: Greg Juhn, M.T.P.W., David R. Eltz, Kelli A. Stacy. Previously reviewed by Jenifer K. Lehrer, MD, Department of Gastroenterology, Frankford-TorresdaleHospital, Jefferson Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network (7/28/2006).

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