What is Blind Loop Syndrome?
Blind loop syndrome (BLS), sometimes also called stagnant loop syndrome, is a rare condition that can cause problems with the absorption of food in the intestines. This condition is becoming an increasing concern for doctors who specialize in gastrointestinal (digestive system) problems. BLS can happen as a result of different health problems, including structural issues in the body, issues with the movement of food through the digestive tract, or inflammation.
This condition involves a part of the small intestine where food stops moving and creates a chance for too much bacteria to grow. Normally, the small intestine has few mixed types of bacteria, less than 1,000 in a small volume of fluid. But in static, or non-moving conditions like in BLS, this number grows. In BLS, non-moving food allows types of bacteria like Bacteroides, E. coli, Streptococcus, and Lactobacillus to multiply in very high numbers. Because of this overgrowth of bacteria, the body has trouble digesting food and absorbing nutrients, which can lead to malnutrition, lack of enough B12 vitamin, and steatorrhea, a condition where there’s too much fat in the stool.
What Causes Blind Loop Syndrome?
There are several physical abnormalities that can occur in the body, and these are often the most common:
- A type of complication called Afferent loop syndrome. This usually happens after specific surgical procedures like Billroth II, Roux-en-Y, or Whipple.
- Issues that can develop after surgery like fistulas (abnormal connections between organs), strictures (narrowing of the organs), or scarring.
- Anastomosis, which is the connection made between two parts of the body during surgery.
- Jejunal diverticulosis, a condition where small pouches form in the jejunum, part of your small intestine.
Certain disorders that affect how your body moves can also cause problems:
- Scleroderma, a group of diseases causing hardening and tightening of the skin and connective tissues.
- Parkinson’s disease, a nervous system disorder that affects movement.
- Diabetic gastroparesis, a condition where the movement of food through the digestive system is delayed due to nerve damage from diabetes.
Some inflammatory diseases can also be responsible for these issues:
- Crohn’s disease, a type of inflammatory bowel disorder.
- Radiation enteritis, an inflammation and damage of the intestines that occurs after radiation therapy.
- Diverticulitis, an inflammation or infection of small pouches called diverticula that can form in your digestive system.
- Celiac disease, an autoimmune disease where the ingestion of gluten leads to damage in small intestine.
Risk Factors and Frequency for Blind Loop Syndrome
It’s hard to know exactly how often this condition occurs because the symptoms can be unclear, and doctors often don’t investigate it or they mistake it for something else.
Signs and Symptoms of Blind Loop Syndrome
Bile acid malabsorption (BLS) is a condition with symptoms that can vary significantly from person to person. To make the diagnosis, doctors need a detailed medical history and a comprehensive physical examination. Informing your doctor about previous surgeries or health conditions could help them understand your situation. Even though it’s often hard to identify, here are the common symptoms associated with BLS:
- Megaloblastic Anemia: This often happens due to a deficiency in vitamin B12 and sometimes in combination with low folate levels.
- Diarrhea/Steatorrhea: The specifics depend on the root cause and how much of the bowel is affected. This symptom also contributes to weight loss.
- Malnutrition: This can occur due to damage to the intestines and the body’s inability to absorb fats. Fatty acids that aren’t absorbed may bind with dietary calcium, leading to a calcium deficiency. These deficiencies may show up in different ways:
- Vitamin A deficiency: dry eyes, difficulty seeing at night, and skin thickening
- Vitamin D deficiency: overactivity of the parathyroid gland, muscle weakness, and fractures
- Vitamin K deficiency: easy bruising, black stool, blood in urine, and heavy menstruation
- Vitamin E deficiency: nerve issues, involuntary eye movements, and muscle disease
- Calcium deficiency: brittle bones, seizures, and prolonged heart electrical activity
- Protein Loss: This can appear as severe skinny condition or water retention in the body.
- Other general symptoms: Widespread, severe, and wave-like stomach ache, nausea, excessive belching, bloating, and gas.
Testing for Blind Loop Syndrome
Radiologic Imaging
Diagnostic imaging is a helpful tool used for examining a condition called blind loop syndrome. Different types of medical imaging studies may be used, including x-rays, CT scans, barium series, and CT enterography. Even though abdominal x-rays and CT scans are straightforward and cost-effective, they are not always the most effective for diagnosing this syndrome. If x-rays or CT scans show signs of blockage or expansion, doctors will usually order more detailed tests if blind loop syndrome is suspected.
Barium studies, which involve swallowing a substance called barium to allow doctors to see your digestive system on an x-ray, can be very useful. They give more information about the structure and movement of your bowel. These tests can also show abnormalities such as small pouches in your intestine (jejunal diverticula), narrow sections of your intestine (intestinal strictures), and abnormal connections between different parts of your bowel (fistulas). However, the best test for finding the mechanical causes of overgrowth is CT enterography. While this is similar to the barium series, it is more sensitive and gives a more detailed picture.
Breath Tests and Cultures
If your doctor strongly suspects that you might have blind loop syndrome, they might order some additional tests. These might include tests that examine your feces for fat, hydrogen breath tests, D-xylose absorption tests, bile acid breath tests, or tiny samples taken from your small intestine (small bowel aspiration).
The fecal fat test can confirm if your body is not absorbing fat properly. It’s a good first test, but it’s not particularly useful for diagnosing this condition. The hydrogen breath test and D-xylose absorption test, which monitor for bacterial overgrowth, are not especially good at diagnosing blind loop syndrome. The bile acid breath test, on the other hand, is more specific and can check for both bacterial overgrowth and problems absorbing bile acids.
To confirm a diagnosis, it may be necessary to take samples from your small intestine and grow them in a lab (a procedure called culturing). However, this process is less commonly used for diagnosis because it can be invasive, expensive, and time-consuming.
The Schilling Test
In the past, the Schilling test was commonly used to confirm the presence of a blind loop. This test involved measuring a substance called cobalamin in your urine. The patterns of cobalamin in your urine in a blind loop were similar to those in a condition called pernicious anemia, but would improve with the use of antibiotics. Even though it was helpful in diagnosing blind loop syndrome, most medical centers consider this test outdated and it has not been replaced.
Treatment Options for Blind Loop Syndrome
Blind loop syndrome is a condition that involves excessive bacterial growth in your gut, leading to deficiencies and unwanted symptoms. Managing this condition means reducing the amount of bacteria, correcting any deficiencies, and handling the symptoms associated with it.
Historically, doctors would prescribe a certain type of antibiotic called tetracyclines to eliminate the bacteria. However, recent studies have suggested that other therapies, particularly antibiotics like rifaximin and metronidazole, may be more effective. Usually, the treatment lasts for about 7 to 10 days. While for most people, one course of antibiotics is enough, sometimes the condition can come back. If this happens, your doctor might try a different treatment to prevent the bacteria from becoming resistant to the antibiotics.
In some cases, if there is a physical reason for the blind loop syndrome or if the syndrome keeps coming back despite using antibiotics, doctors might suggest surgery. The aim of the surgery is to correct the physical problem causing the syndrome, remove any sections of the gut that are causing issues, and ensure a well-functioning gut. The surgery performed will depend on the exact issue you’re having. For example, if you have a stricture or a non-working loop in your gut causing this syndrome, the doctor may perform a procedure to widen the stricture or remove the loop.
Aside from these treatments, it’s also important to make sure you’re getting enough nutrition, particularly if you’ve lost a lot of weight because of the disease. Depending on your specific situation, you may need a diet high in calories, low in fat, and with supplemented vitamins or minerals. Your doctor will guide you on this aspect if necessary. For instance, if you’ve developed an intolerance to milk sugar (lactose) as a result of the condition, your doctor will advise you on dietary changes to consider.
What else can Blind Loop Syndrome be?
Irritable bowel syndrome (IBS) is an ailment where the actual cause is not fully understood. People who have IBS often talk about belly pain that gets better after using the restroom, changes in how often they poop, and the look and feel of the stool itself. This disease is similar to BLS (Blind Loop Syndrome) but does not show other deficiencies that BLS does.
Celiac disease is a type of condition where the body’s immune system attacks its own tissues. It causes damage to the lining of the small intestine. People with this disease often suffer from chronic diarrhea, a bloated feeling, weight loss, and a lack of vitamin B12. Gluten in the diet usually causes these issues. Despite similarities to BLS, celiac disease has its own unique antibodies in response to gluten.
Tropical sprue is a disease where the body doesn’t absorb nutrients properly. Like BLS, tropical sprue patients also have diarrhea and are deficient in vitamin B12. However, this illness is commonly found in certain geographical areas and has its own unique causes and characteristics.
Whipple disease is a type of disease that also prevents the gut from absorbing nutrients properly. Symptoms include weight loss, diarrhea, and general indigestion symptoms. On physical check-up, patients might show signs of confusion, joint pain, and swollen lymph nodes. The disease can be diagnosed through a biopsy that shows the presence of a specific bacterium, T whipplei.
Pancreatic insufficiency is a condition where the pancreatic gland does not work correctly. People with this disease, particularly those who’ve previously had pancreatitis may show signs of diarrhea with a lot of fat, weight loss, and deficiencies of certain nutrients that dissolve in fats. Doctors might use a D-xylose test to distinguish this from BLS by checking the health condition of the bowel lining.
Crohn’s disease is a type of inflammation of the bowels. It shows features like nodules and inflammation that affects the entire thickness of the bowel wall. Commonly, Crohn’s disease affects the final part of the small intestine leading to symptoms like watery diarrhea, fat-laden stool, and a shortage of vitamin B12. Unlike BLS, Crohn’s disease can also cause problems outside the gut, including eye inflammation and skin redness that hurts when touched. A biopsy of the colon is required to confirm this diagnosis.
What to expect with Blind Loop Syndrome
The outlook for BLS, or Bernard-Soulier syndrome, depends on two main factors. The first is the cause of the syndrome, and the second is how much the syndrome has advanced or progressed.
Possible Complications When Diagnosed with Blind Loop Syndrome
Subacute combined degeneration is a serious brain complication associated with blind loop syndrome, a digestive disorder. When harmful bacteria overgrow in the intestine, they limit the absorption of vitamin B12. Over time, this deficiency can lead to damage in certain nerve pathways. This condition can cause symptoms like a pricking or tingling sensation in the skin (paresthesia), lack of coordination (ataxia), and loss of awareness of body positioning (positional sense). If left untreated, it can lead to more severe symptoms like muscle spasms (spasticity) or even paralysis of the legs (paraplegia).
Osteomalacia is a potential side effect of blind loop syndrome. It is a condition where a long-term deficiency in vitamin D due to poor fat absorption leads to the softening of the bones. It can cause symptoms like bone pain, joint pains (arthralgias), or muscle weakness closest to the center of the body (proximal muscle weakness). It’s important to identify and treat this condition to prevent fractures due to weakened bone strength.
Another rare and serious complication associated with blind loop syndrome is retroperitoneal hemorrhage, a type of internal bleeding. Poor fat absorption caused by the disorder can lead to a deficiency in vitamin K. Since this vitamin plays an essential part in forming blood clots, a deficiency can make it harder for the blood to clot (hypocoagulable state). This can lead to uncontrolled bleeding and shock during surgery. Because this complication has a mortality rate of about 18%, it’s important for doctors to consider this risk before surgery.
Common Complications:
- Subacute combined degeneration causing paresthesia, Ataxia, and loss of positional sense
- Osteomalacia causing bone pain, arthralgias, and proximal muscle weakness
- Retroperitoneal hemorrhage leading to uncontrolled intraoperative bleeding and potential hemorrhagic shock
Preventing Blind Loop Syndrome
It’s very important to teach people who are at risk about how this illness shows itself. When people are properly informed, they can recognize the signs of the disease quicker. This can speed up the process of getting a diagnosis, preventing the disease from getting worse. Additionally, just by helping people understand, we can greatly reduce the number of people affected by the disease and the health issues they face after gastrointestinal surgery.
