Blind Loop Syndrome

What is blind loop syndrome?

Your digestive system breaks down the food you eat so your body can use it for fuel. Food moves from your stomach into your small intestine. There, nutrients are absorbed. The excess food is pushed into the colon and leaves the body as waste.

In blind loop syndrome, food is not able to follow the normal digestive route. Instead, it bypasses a section of your intestine.

Blind loop syndrome is also called:

  • Stasis syndrome
  • Stagnant loop syndrome
  • Bowel bypass syndrome.

What causes blind loop syndrome?

Blind loop syndrome is often due to an overgrowth of bacteria in the intestine. This forces food to route around it. Because of the "blind loop" that is formed, the small intestine is shorter than normal. The intestines can’t properly absorb nutrients. They are instead passed out of your body in waste.

Blind loop syndrome often occurs as a complication of abdominal surgery. The most common type of surgery that causes this is bowel-shortening surgery for obesity. In this surgery, part of the intestine is purposely bypassed.

Digestive problems may also trigger blind loop syndrome. It may occur as a complication of:

  • Diverticulitis
  • Peptic ulcer disease
  • Inflammatory bowel disease (Crohn's disease and colitis)
  • Other conditions or medicines that delay movement of nutrients through the intestine.

What are the symptoms of blind loop syndrome?

One of the main symptoms of blind loop syndrome is unexplained weight loss. This occurs when your small intestine can't digest food and absorb nutrients. When your body isn’t getting the nutrients and fat it needs, weight loss occurs.

If severe bacterial overgrowth occurs it can rarely inflame your intestinal lining. And in a few cases the intestinal bacteria can get into the blood. This bacterial infection can cause:

  • Fever
  • Arthritis-like joint pain
  • Skin rash or red bumps on the skin
  • Inflamed tendons
  • Muscle pain or aches

Poor absorption of nutrients and poor nutrition can cause a number of symptoms, such as:

  • Frequent diarrhea
  • Nausea or vomiting
  • Belly (abdominal) swelling from fluid buildup
  • Swelling of the legs
  • Belly pain and cramping
  • Stools that seem loose and fatty
  • Fatigue or weakness
  • Gas and bloating

How is blind loop syndrome diagnosed?

Your healthcare provider will ask about your symptoms, your medical, surgical, and family history. He or she will request tests to test for nutrient absorption, anemia, or to rule out other conditions. Tests may include:

  • Blood tests to check for infections and nutrition status
  • Breath tests to look for bacterial overgrowth
  • Tests to check organ function
  • Test to check for inflammation in the body
  • Exam of stool for fecal fat, stool culture, parasites, white blood cells
  • Imaging tests to evaluate the intestinal anatomy
  • Possible colonoscopy or upper endoscopy to evaluate the intestinal lining

How is blind loop syndrome treated?

Healthcare providers can treat blind loop syndrome. You will likely take antibiotics. A short course of corticosteroids to reduce inflammation may also help control symptoms.

Sometimes you need surgery to remove the infected area. If obesity surgery caused blind loop syndrome, your surgeon may do another surgery to fix the problem.

What are the complications of blind loop syndrome?

If left untreated, blind loop syndrome may lead to poor nutrition.  But even early on, blind loop syndrome can cause a lack of vitamins and minerals, including Vitamin B 12 and iron.

When should I call my healthcare provider?

If you notice any symptoms of blind loop syndrome, it's important to tell your healthcare provider. Be aware of the condition if you’ve had abdominal surgery or have a digestive disease such as inflammatory bowel disease. Blind loop syndrome can be treated. But if nutrients can’t be absorbed, it can cause serious health problems.

Key points

  • Blind loop syndrome occurs when food doesn't follow the normal digestion route and bypasses a section of your intestine.
  • It can be caused by abdominal surgery, diverticulitis, inflammatory bowel disease, peptic ulcer disease, or an infection.
  • One of the main symptoms of blind loop syndrome is unexplained weight loss. Gas and bloating are common from bacterial overgrowth.
  • Other symptoms include fever and infection-type symptoms, and diarrhea, vomiting, and abdominal pain and swelling.
  • Blind loop syndrome is usually treated with antibiotics. Surgery may also be needed.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Medical Reviewer: Jen Lehrer MD
Medical Reviewer: John Hanrahan MD
Medical Reviewer: Raymond Kent Turley BSN MSN RN
© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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