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Blind Loop Syndrome

What is blind loop syndrome?

Blind loop syndrome is caused when a part of the small intestine slows down. It doesn't digest and absorb food normally.

Your digestive system breaks down the food you eat. Then your body can use it for fuel. Food you eat moves from your stomach into your intestines (bowels). Nutrients are absorbed, or taken in, there. The waste is pushed into the colon and leaves the body as poop (feces or stool).

Blind loop syndrome is also called:

  • Stasis syndrome.
  • Stagnant loop syndrome.
  • Bowel bypass syndrome.
  • Small intestinal bacterial overgrowth (SIBO).

What causes blind loop syndrome?

The intestine has a system of movements known as "peristalsis." These move food, secretions, and bacteria through your digestive tract. After some types of surgery, or for other reasons, a loop of bowel moves less or stops. Bacteria then overgrow in that area. This affects digestion and your body taking in important nutrients like vitamin B12, fats, and nutrients that dissolve in fat. The lack of these nutrients can cause symptoms.

Blind loop syndrome may be caused by any of these:

  • Abdominal surgery such as surgery to remove part of the small intestine (small bowel resection).
  • Obesity (bariatric) surgery that shortens and bypasses part of the bowel. 
  • Surgical problems(fistulas, strictures, scarring).
  • Digestive problems.
  • Small intestine diverticulosis.
  • Surgery for peptic ulcer disease.
  • Inflammatory bowel diseases such as Crohn's disease, celiac disease, radiation enteritis, and colitis.
  • Medicines that slow the intestines.
  • Conditions that slow the intestines, such as diabetes gastroparesis, Parkinson's disease, and scleroderma.

What are the symptoms of blind loop syndrome?

Symptoms often include:

  • Weight loss due to trouble absorbing nutrients.
  • Gas.
  • Bloating.
  • Bulging belly (abdomen).
  • Diarrhea.
  • Loose, greasy, bad-smelling stools.

Poor absorption of nutrients can cause symptoms such as:

  • Frequent diarrhea.
  • Nausea or vomiting.
  • Belly (abdominal) swelling from fluid buildup.
  • Swelling of the legs.
  • Belly pain and cramping.
  • Poop that is loose and fatty.
  • Tiredness or weakness, light-headedness or fainting.
  • Gas, burping, passing gas (flatulence), and bloating.
  • Low levels of some vitamins.

In rare cases, severe overgrowth of bacteria can inflame your intestinal lining. Also in rare cases, the bacteria can get into the blood. This infection can cause:

  • Fever.
  • Joint pain that feels like arthritis.
  • Skin rash or red bumps on the skin.
  • Inflamed tendons.
  • Muscle pain or aches.
  • Altered mental status, slurred speech, and seizures in severe cases.

How is blind loop syndrome diagnosed?

Your healthcare provider will ask about your:

  • Symptoms.
  • Health history.
  • History of surgery.
  • Family health history.

You may have tests such as:

  • Blood tests to check for infections and nutrient levels.
  • Breath tests:
    • bile acid breath test to look for bacterial overgrowth and bile acid malabsorption..
    • carbohydrate breath test to look for bacterial overgrowth.
  • Tests to check organ function.
  • Test to check for inflammation in the body.
  • Exam of poop for fecal fat, bacteria, parasites, or white blood cells.
  • Imaging tests to look at the shape of your intestines. These may include barium X-rays and CT enterography.
  • Colonoscopy or upper endoscopy to look at the intestinal lining.

How is blind loop syndrome treated?

Blind loop syndrome is most often treated with antibiotics. Corticosteroids can reduce inflammation. They may also help control symptoms.

Some people need surgery to remove the affected area. If obesity surgery caused blind loop syndrome, your surgeon may do another surgery to fix the problem.

What are possible complications of blind loop syndrome?

Blind loop syndrome can cause a lack of vitamins and minerals. This includes Vitamin B12 and iron. If not treated, blind loop syndrome may lead to serious health problems due to poor nutrition.

When should I call my healthcare provider?

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

Key points

  • Blind loop syndrome occurs when part of your small intestine doesn't push food normally. It then causes bacteria to overgrow in the intestines.
  • Abdominal surgery, some diseases, and some medicines can cause it.
  • Symptoms include weight loss, gas, and bloating. Other symptoms can include fever, diarrhea, vomiting, and belly pain.
  • It's usually treated with antibiotics, vitamin and mineral supplements, and changes to your diet. Some people may need surgery.

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. Note any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why your provider prescribed a new medicine or treatment 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 don't take the medicine or have the test or procedure.
  • If you have a follow-up visit, write down the date, time, and purpose for that visit.
  • Know how you can contact your healthcare provider if you have questions.