Small Intestinal Bacterial Overgrowth

Small Intestinal Bacterial Overgrowth, commonly called SIBO, means that an excessive amount of bacteria are present in the intestine or “gut”. While bacteria are essential for proper digestion, the majority of gut bacteria reside in the colon. When the number of bacteria in the small bowel increase, sometimes because they have migrated backward from the colon into the small intestine, it can lead to digestive distress, poor nutrient absorption, and even a leaky gut, where toxins and bacteria leak through the intestinal wall.

If you would like to consult with a provider about your symptoms, schedule an appointment with Virginia Mason's Gastroenterology Department by calling (206) 223-2319.

Symptoms of SIBO

Signs and symptoms of SIBO can include:

  • Abdominal pain, especially after eating
  • Bloating
  • Chronic fatigue
  • Constipation
  • Diagnosis of irritable bowel syndrome — IBS, or inflammatory bowel disease — IBD
  • Diarrhea
  • Excessive intestinal gas
  • Fat malabsorption, signified by pale, bulky, and foul-smelling stools
  • Rosacea and other skin rashes
  • Weight loss

Diagnosing SIBO

SIBO is associated with a number of chronic conditions such as immune disorders, slow or disturbed bowel motility, and conditions that cause bacteria from the colon to reflux into the small bowel. Examples of these conditions include celiac disease, cirrhosis, chronic pancreatitis, Crohn's disease, diverticulitis, and gastroparesis. SIBO is also associated with diabetes or scleroderma that can cause damage to the nerves in the gut, medications that disrupt normal gut flora such as antibiotics, acid-blockers, narcotics, and steroids, and surgeries that cause gut narrowing or hooking together loops of small intestine or small intestine to the colon.

To explore the cause a SIBO, a gastroenterologist will complete a thorough medical history and a physical exam, which may include gently feeling your abdomen. Tests may be ordered, which may include:

  • Biopsy: Using a thin, flexible tube inserted through the mouth into the intestine, a small piece of tissue can be removed and examined under a microscope.
  • Breath test: A noninvasive breath test can identify hydrogen and methane gasses, which are caused by excess bacteria in the small intestine.
  • Stool tests: This test is used to test for multiple gut infections and to measure the flora (bacteria) of the intestines.
  • Urine tests: By-products of yeast in the intestine are excreted in urine and can indicate bacterial overgrowth.

Treatment of SIBO

To effectively treat SIBO, your gastroenterologist will prescribe medication and a diet aimed to:

  1. Eliminate the bacteria
  2. Restore normal movement of your intestine
  3. Repair the intestinal lining

Most patients require multiple courses of various treatments to achieve long-lasting results.

Medical Therapy

  • A pro-kinetic, a drug that increases gut motility, may be prescribed to address the underlying dysfunction of motility.
  • Since the gut and the brain share chemical receptors, drugs that have been traditionally used for anxiety or depression are sometimes used to improve gut motility.
  • Antibiotics can eliminate bacteria within the small intestine, relieve symptoms, and reduce gas.
  • Specific probiotics can restore normal gut flora and help repair damage to the intestinal lining.

Nutrition & Dietary Intake

  • Your provider may recommend that you eat small and frequent meals in order to avoid large amounts of food sitting in the stomach.
  • You may be advised to avoid sugar, alcohol, and carbohydrates, foods and drinks that feed the bacteria.
  • A balanced and nutritious diet including non-starchy vegetables, leafy greens, lean proteins, and healthy fats may be recommended.

To schedule an appointment with Virginia Mason's Gastroenterology Department, call (206) 223-2319.