Small Bowel Obstruction

Small bowel obstruction means the small intestine is partially or totally blocked. When this happens, the contents of the intestine cannot properly get out of the body. Stools, fluid, and gas build up inside the intestine. This is a potentially serious condition that requires urgent medical care.

  • Causes

    Bowel obstruction may be caused by a mechanical problem. In this case, something inside the body blocks the movement of material through the intestine.


    It can also be caused by an ileus, which is when the intestine itself does not work right. This nonmechanical type of obstruction is called
    paralytic ileus, or
    pseudo-obstruction. It is often the cause of obstruction in infants and children.


    Mechanical small bowel obstruction may be caused by:

    • Adhesions—scar tissue left behind, in most cases by previous abdominal surgery
    • Intussusception—telescoping of the intestinal wall
    • Volvulus—the intestine twists on itself
    • Impacted foreign bodies—lis that were swallowed and got stuck


    Paralytic ileus may be caused by surgery on the intestine or certain medications, such as opioids.

    Small Bowel Obstruction
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  • Definition

    Small bowel obstruction means the small intestine is partially or totally blocked. When this happens, the contents of the intestine cannot properly get out of the body. Stools, fluid, and gas build up inside the intestine. This is a potentially serious condition that requires urgent medical care.

  • Diagnosis

    Your doctor will ask about your symptoms and medical history. A physical exam will be done. The exam will include listening for bowel sounds in your stomach. Very high pitched bowel sounds heard through a stethoscope suggest mechanical bowel obstruction. Conversely, paralytic ileus often produces no bowel sounds.


    Imaging tests are used to evaluate abdominal structures. These may include:

    • CT scan
    • MRI scan
    • X-ray
    • Ultrasound

  • Prevention

    There are no current guidelines to prevent small bowel obstruction. Managing any underlying conditions, such as Crohn’s disease, can reduce your chances.

  • Risk Factors

    Factors that may increase your chance of having a small bowel obstruction include:

    • Hernias
    • Crohn’s disease—an inflammatory bowel condition
    • Abdominal, joint, or spine surgery
    • Swallowing a foreign body
    • Decreased blood supply to the small bowel
    • Abnormal growth of tissue in or next to the small intestine
    • Tumors in the small intestine
    • Cancer
    • Infection in the lining of the small intestine
    • Kidney disease

    • Long-standing
      diabetes
    • Rarely,
      gallstones

  • Symptoms

    Symptoms of small bowel obstruction often occur in combination. Small bowel obstruction may cause:

    • Abdominal fullness and/or excessive gas
    • Distension—abdomen feels stretched out more than normal
    • Pain and cramps in stomach area
    • Vomiting
    • Constipation
    • Diarrhea
    • Bad breath


    Paralytic ileus pain is often less severe than mechanical small bowel obstruction.

  • Treatment

    Treatment depends on the cause and severity of the obstruction. You will usually require treatment by a specialist. Your doctor will also treat you for any underlying conditions that contribute to small bowel obstruction.