Small Intestinal Bacterial Overgrowth (SIBO)

  • Medical Author:
    Benjamin Wedro, MD, FACEP, FAAEM

    Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

  • Medical Editor: Bhupinder S. Anand, MBBS, MD, DPHIL (OXON)
    Bhupinder S. Anand, MBBS, MD, DPHIL (OXON)

    Bhupinder S. Anand, MBBS, MD, DPHIL (OXON)

    Dr. Anand received MBBS degree from Medical College Amritsar, University of Punjab. He completed his Internal Medicine residency at the Postgraduate Institute of medical Education and Research, Chandigarh, India. He was trained in the field of Gastroenterology and obtained the DPhil degree. Dr. Anand is board-certified in Internal Medicine and Gastroenterology.

Irritable Bowel Syndrome (IBS) Facts

How is the diagnosis of SIBO made?

The initial symptoms of small intestine bacterial overgrowth are non-specific and it may take time for the person and health care professional to consider SIBO as a potential cause. The clues may come from illnesses associated with malabsorption of proteins, fats and vitamins and it is important to look for those causes, as well as the potential for SIBO.

Blood tests may be ordered looking for different causes of anemia, electrolyte imbalance, and vitamin deficiencies.

Breath tests may be considered to measure the byproducts of digestion, especially those that are dependent upon bacteria in the intestine. Interpreting the test results may help make the diagnosis of SIBO without having to perform an endoscopy or biopsy.

Upper GI endoscopy allows a gastroenterologist to look at the inside of the upper part of the small intestine and take biopsies or small bits of tissue that can be examined under the microscope. Samples of the fluid from the duodenum and jejunum can be analyzed looking for abnormalities that are associated with SIBO.

While these diagnostics tests are being performed, it is appropriate for the health care professional to look for conditions that are associated with SIBO. If such a condition is already known, then maximizing treatment of the associated condition may be undertaken at the same time the diagnosis of SIBO is being considered and tested for.

What is the treatment for SIBO?

The treatment for SIBO includes controlling and treating any underlying associated illness. The goal is to control the symptoms of small intestine bacterial overgrowth since it may not be possible to "cure" the disease.

Antibiotics are one of the treatments that are helpful in controlling the excess bacteria. It is important that not all the bacteria in the intestine are eradicated, since some are required to help with normal digestion.

Amoxillin-clavulanate (Augmentin) and rifamaxin (Xifaxan) are the two common first line antibiotics that may be prescribed. Depending upon the situation, other antibiotics may also be considered, including clindamycin, metronidazole (Flagyl), floxins (ciprofloxacin [Cipro, Cipro XR, Proquin XR], levofloxacin [Levaquin]) and trimethoprim-sulfamethoxazole (Bactrim, Septra).

While a single course of antibiotics for 1-2 weeks may be sufficient, SIBO has a tendency to relapse, and sometimes repeated courses of antibiotics may be required. In some people, the antibiotics will be routinely cycled, meaning that they will alternate a 1-2 weeks on the antibiotic with 1-2 weeks off.

In addition, underlying vitamin and nutrient deficiencies due to malabsorption should be treated.

Medically Reviewed by a Doctor on 3/16/2016

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