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Blind loop syndrome

Definition

Blind loop syndrome occurs when digested food slows or stops moving through part of the intestines. This causes an overgrowth of bacteria in the intestines. It also leads to problems absorbing nutrients.

Alternative Names

Stasis syndrome; Stagnant loop syndrome; Small bowel bacterial overgrowth

Causes

The name of this condition refers to the "blind loop" formed when part of the intestine is bypassed. This blockage does not allow digested food to flow normally through the intestinal tract.

The substances needed to digest fats (called bile salts) do not work as they should when a section of the intestine is affected by blind loop syndrome. This prevents fat and fat-soluble vitamins from being absorbed into the body. It also leads to fatty stools. Vitamin B12 deficiency may occur because the extra bacteria that form in the blind loop use up this vitamin.

Blind loop syndrome is a complication that occurs:

Diseases such as diabetes or scleroderma may slow down movement in a segment of the intestine, leading to blind loop syndrome.

Symptoms

Symptoms include:

Exams and Tests

During a physical exam, the health care provider may notice a mass in, or swelling of the abdomen. Possible tests include:

Treatment

Treatment most often starts with antibiotics for the excess bacteria growth, along with vitamin B12 supplements. If antibiotics are not effective, surgery may be needed to help food flow through the intestines.

Outlook (Prognosis)

Many people get better with antibiotics. If surgical repair is needed, the outcome is often very good.

Possible Complications

Complications may include:

When to Contact a Medical Professional

Contact your provider if you have symptoms of blind loop syndrome.

Gallery

Digestive system
The esophagus, stomach, large and small intestine, aided by the liver, gallbladder and pancreas convert the nutritive components of food into energy and break down the non-nutritive components into waste to be excreted.
Stomach and small intestine
The stomach connects the esophagus to the small intestines and is where the majority of food digestion takes place.
Roux-en-Y stomach surgery for weight loss
The Roux-en-Y gastric bypass procedure involves creating a stomach pouch out of a small portion of the stomach and attaching it directly to the small intestine, bypassing a large part of the stomach and duodenum. Not only is the stomach pouch too small to hold large amounts of food, but by skipping the duodenum, fat absorption is substantially reduced.

References

Gan T, Evers BM. Small intestine. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. 21st ed. St Louis, MO: Elsevier; 2022:chap 50.

Shamir R. Disorders of malabsorption. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 364.

Last reviewed October 26, 2021 by Michael M. Phillips, MD, Emeritus Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team..

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