Small Bowel Bacterial Overgrowth

Small bowel bacterial overgrowth (SBBO) occurs when there is a build-up of too much bacteria in the small bowel.

  • Causes

    SBBO is often caused by an abnormality in the small bowel. Food is not able to flow properly though the intestines. Conditions that may cause this include:

    • Birth defect
    • Injury
    • Surgery
    • Conditions (eg, digestive disorder)

  • Definition

    Small bowel bacterial overgrowth (SBBO) occurs when there is a build-up of too much bacteria in the small bowel.

    The Small Intestines
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  • Diagnosis

    SBBO can be difficult to diagnose. The symptoms may be similar to other conditions. Your doctor will:

    • Ask about your symptoms and medical history
    • Do a physical exam

    • Order tests, such as:

      • Blood tests to detects nutritional deficiencies (eg,
        B12 deficiency
      • Breath tests—involves fasting, eating some type of sugar, and then exhaling into a bag; the sample is analyzed to find out if there are levels of certain gases
      • Culture of intestinal fluid (aspirate)—a catheter is used to get a sample of fluid from the small bowel

  • Prevention

    If you have any of the conditions that are linked to SBBO, get proper treatment. This may reduce your chance of having a build-up of bacteria in the small bowel.

  • Risk Factors

    Examples of conditions that may increase the risk of SBBO include:

    • Crohn’s disease
    • Irritable bowel syndrome
    • Short bowel syndrome
    • Diverticulitis
    • Intestinal stricture (narrowing in the small intestine)

    • Digestive disorders (eg,
      celiac disease
      lactose intolerance
    • Blind loop syndrome (when part of the intestine is bypassed)

    • Intestinal infection (eg,
      food poisoning
      traveler’s diarrhea
    • Cirrhosis
    • Diabetes

    • Chronic

    • End-stage
      or liver disease

    Other risk factors include:

    • Intestinal surgery (eg,
      removal of part of the small intestine
    • An obstruction in the small intestine
    • Weakened immune system
    • Being elderly (more likely to have conditions like diverticulitis)

    Any condition that affects how food moves through the small bowel may increase the risk of SBBO.

  • Symptoms

    Not all patients with SBBO will have symptoms. But symptoms may include:

    • Abdominal pain
    • Bloating and gas
    • Feeling of fullness
    • Constipation

    • Nutritional deficiencies (eg,
      vitamins B12
    • Weight loss

  • Treatment

    The goals are to:

    • Reduce the levels of harmful bacteria in the small bowel
    • Treat the underlying condition