Small bowel bacterial overgrowthOvergrowth - intestinal bacteria; Bacterial overgrowth - intestine; Small intestinal bacterial overgrowth; SIBO
Small bowel bacterial overgrowth is a condition in which very large numbers of bacteria grow in the small intestine.
Most of the time, the small intestine does not have a high number of bacteria. Excess bacteria in the small intestine may use up the nutrients needed by the body. As a result, a person may become malnourished .
Malnutrition is the condition that occurs when your body does not get enough nutrients.
The breakdown of nutrients by the excess bacteria can also damage the lining of the small intestine. This can make it even harder for the body to absorb nutrients.
Conditions that can lead to overgrowth of bacteria in the small intestine include:
Complications of diseases or surgery that create pouches or blockages in the small intestine.
is one of these conditions.
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Diseases that lead to movement problems in the small bowel, such as
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Immunodeficiency such as
or immunoglobulin deficiency.
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Short bowel syndrome
caused by surgical removal of the small intestine.
Short bowel syndrome
Short bowel syndrome is a problem that occurs when part of the small intestine is missing or has been removed during surgery. Nutrients are not prop...
- Small bowel diverticulosis, in which small sacs occur in the inner lining of the intestine. These sacs allow too many bacteria to grow. These sacs are much more common in the large bowel.
Surgical procedures that create a loop of small intestine where excess bacteria can grow. An example is a Billroth II type of stomach removal (
Gastrectomy is surgery to remove part or all of the stomach. If only part of the stomach is removed, it is called partial gastrectomyIf the whole sto...
- Some cases of irritable bowel syndrome (IBS).
The most common symptoms are:
- Abdominal fullness
- Abdominal pain and cramps
- Diarrhea (usually watery)
Other symptoms may include:
- Fatty stool
- Weight loss
Exams and Tests
Your health care provider will perform a physical exam and ask about your medical history. Tests may include:
- Blood chemistry tests (such as albumin level)
Complete blood count (
A complete blood count (CBC) test measures the following:The number of red blood cells (RBC count)The number of white blood cells (WBC count)The tota...
Fecal fat test
Fecal fat test
The fecal fat test measures the amount of fat in the stool. This can help gauge the percentage of dietary fat that the body does not absorb....
X-rays are a type of electromagnetic radiation, just like visible light. An x-ray machine sends individual x-ray particles through the body. The im...
- Vitamin levels in the blood
- Small intestine biopsy or culture
- Special breath tests
The goal is to treat the cause of the bacterial overgrowth. Treatment most often consists of antibiotics. In some cases, drugs that speed intestinal movement (motility-speeding drugs) may be used. A low carbohydrate diet can be helpful.
Treatment also involves getting enough fluids and nutrition. A person who is dehydrated may need intravenous (IV) fluids in a hospital. A person who is malnourished may also need nutrition given through a vein (total parenteral nutrition -- TPN).
Severe cases lead to malnutrition. Other possible complications include:
Dehydration occurs when your body does not have as much water and fluids as it should. Dehydration can be mild, moderate, or severe, based on how muc...
- Excess bleeding due to vitamin deficiency
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Manolakis CS, Rutland TJ, Di Palma JA. Small intestinal bacterial overgrowth. In: McNalley PR, ed. GI/Liver Secrets Plus . 5th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 44.
Quigley EMM. Small intestinal bacterial overgrowth. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease . 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 105.
Urinary tract infection
Review Date: 5/11/2016
Reviewed By: Subodh K. Lal, MD, gastroenterologist with Gastrointestinal Specialists of Georgia, Austell, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.