Blind Loop Syndrome

Definition of Blind Loop Syndrome

Blind loop syndrome abbreviated as BLS, is also called as stagnant loop syndrome or stasis syndrome. It occurs when a certain region forms a loop within the small intestine where food contents pass through during digestion.

blind loop syndrome image

If this blind loop is present, the food might not be able to normally move into the digestive tract. Waste products and food that move slowly often becomes a breeding site for bacteria. This results to the overgrowth of bacteria that leads to some symptoms. Blind loop syndrome is typically an abdominal surgery complication, although it could also be a result of some other diseases and structural problems.

Symptoms of Blind Loop Syndrome

Possible signs and symptoms of blind loop syndrome often involve:

  • Sudden fullness after eating a meal
  • Bloating
  • Nausea
  • Loss of appetite
  • Losing weight unintentionally
  • Pain in the abdomen
  • Diarrhea

Diarrhea, bloating, and nausea are common signs and symptoms of many other problems of the intestine. See the physician for a full assessment specially if there had been a history of an abdominal surgery.

Symptoms that need immediate medical care include:

  • Severe pain in the abdomen that lasts for a number of days
  • Fast and unintentional weight loss
  • Diarrhea that persists

Pathology of Blind Loop Syndrome

The small intestine is the longest region of the digestive tract that approximately measures 20 feet or 6.1 meters in length. It is in the small intestine that the mixing of food with digestive nutrients and juices take place before being directly absorbed into the bloodstream. Compared to the colon or large intestine, the small intestine usually has a fewer bacteria. In blind loop syndrome however, the digested food is obstructed by the blind loop through the intestinal tract. In return, stagnant food that remained in the small intestine will be the ideal reason for the development of bacteria. The bacteria present hinder the absorption of nutrients and can create toxins. The greater the length of small intestine involvement in the blind loop, the higher the possibility of bacterial overgrowth.

Blind loop syndrome can be caused by:

  • Structural problems within the small intestine – This includes the intestinal adhesions outside the intestine and small protruding pouches of tissue that bulge all through the intestinal wall
  • Abdominal surgery complications – After many operations have been done such as gastrectomy for treating stomach cancer and peptic ulcers or gastrectomy operation for extreme obesity

Some medical conditions can also slow the motility of waste products and food through the small intestine. These are:

  • Scleroderma
  • Crohn’s disease
  • Diabetes
  • Radiation enteritis
  • Celiac disease
  • Obesity

Treatment of Blind Loop Syndrome

Whenever there is a possibility, physicians treat blind loop syndrome by having to deal with the primary problem like for example, by repairing a stricture, postoperative blind loop, or fistula through a surgical procedure. However, the BLS is not always reversible that is why some treatment options focus on getting rid of bacterial overgrowth and correcting nutritional deficiencies.

Treatment options may include:

  • Antibiotic therapy – Most individuals who have bacterial overgrowth are typically treated with antibiotics first. The physician might perform a test if antibiotic is not effective.
  • Nutritional support – It is a way of correcting nutritional deficiencies specifically to those individuals with severe weight loss.

Helpful treatments are:

  • Lactose-free diet – The capability to digest lactose or milk sugar may be lost due to the damage in the small intestine. In that case, any products with lactose must be avoided.
  • Nutritional supplements – Intramuscular injections of vitamin B-12 may be necessary for patients as well as calcium, vitamins, and iron supplements.
  • Medium-chain triglycerides – Theses are sometimes prescribed by the physician as a dietary supplement for individuals with severe blind loop syndrome.


A lot of patients are cured completely with antibiotics. If surgical treatment is needed per evaluation, it can have a very good prognosis outcome. This usually depends on the cause and severity of the condition and its associated complications.

Life Expectancy

Women have an estimated normal life expectancy once treatment is started for BLS, while the men have slightly subnormal level due to the presence of some greater incidence of stomach carcinoma that exists.


blind loop syndrome


  4. Bures J, Cyrany J, Kohoutova D, et al; Small intestinal bacterial overgrowth syndrome. World J Gastroenterol. 2010 Jun 28; 16(24):2978-90.
  5. Green, Anthony et al. (16 NOV 2010). Postgraduate Haematology, Sixth edition. Wiley Publishers. p 71.
  6. Di Stefano M, Miceli E, Missanelli A, et al; Absorbable vs. non-absorbable antibiotics in the treatment of small intestine bacterial overgrowth in patients with blind-loop syndrome. Aliment Pharmacol Ther. 2005 Apr 15; 21(8):985-92.

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