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Small intestinal bacterial overgrowth (SIBO) occurs when the general bacterial population in the small intestine increases abnormally, particularly species of bacteria not normally seen in that portion of the digestive tract. This disorder is also known as blind loop syndrome.
SIBO often occurs when a factor, such as surgery or disease, restricts the movement of food and waste items through the digestive tract, allowing bacteria to thrive. Excess bacteria frequently induce diarrhea and may result in weight loss and malnutrition.
While SIBO is frequently a consequence of stomach (abdominal) surgery, it can also be caused by structural issues and certain disorders. Surgery is sometimes required to repair the condition, however antibiotics are the most commonly used treatment.
WHAT ARE THE SYMPTOMS OF SIBO?
SIBO symptoms and signs frequently include:
- Appetite loss
- Pain in the abdomen
- Nausea
- Bloating
- An unpleasant sense of fullness after eating
- Diarrhea
- Weight loss that was unintentional
- Malnutrition
WHAT ARE THE CAUSES OF SIBO?
Small intestine bacterial overgrowth (SIBO) can be induced by the following factors:
- Abdominal surgical complications, such as gastric bypass for obesity and gastrectomy for peptic ulcers and stomach cancer
- Scar tissue (intestinal adhesions) that can wrap around the outside of the small bowel and bulging pouches of tissue that protrude through the wall of the small intestine are examples of structural abnormalities in and around the small intestine (intestinal diverticulosis)
- Certain medical diseases, such as Crohn's disease, radiation enteritis, scleroderma, celiac disease, diabetes, or others, might delay the flow of food and waste items through the small intestine (motility).
Why does small intestine bacterial overgrowth (SIBO) occur?
The small intestine is the longest piece of your digestive tract, stretching for around 20 feet (6.1 meters). Food is mixed with digestive juices in the small intestine, and nutrients are absorbed into the bloodstream.
Because of the quick flow of contents and the presence of bile, your small intestine has less microorganisms than your big intestine (colon). In the case of SIBO, however, stagnant food in the bypassed small intestine serves as a great breeding environment for bacteria. The bacteria may create toxins and interfere with nutrient intake. The byproducts of bacterial digestion of food can also cause diarrhea.
WHAT ARE THE RISK FACTORS FOR SIBO?
The following factors enhance your risk of SIBO:
- Obesity or ulcer-related gastric surgery
- A tiny intestinal structural imperfection
- A damage to the small intestine
- A fistula, which is an irregular channel connecting two segments of intestine.
- Crohn's disease, lymphoma of the small intestine, or scleroderma of the small intestine
- Abdominal radiation therapy history
- Diabetes
- Small intestine diverticulosis
- Previous abdominal surgery-induced adhesions
WHAT ARE THE COMPLICATIONS OF SIBO?
Small intestine bacterial overgrowth (SIBO) can lead to a variety of complications, including:
- Fat, carbohydrate, and protein absorption issues: Excess bacteria in the small intestine break down bile salts, which are normally required to metabolize fats, resulting in inadequate fat digestion and diarrhea. Bacterial compounds can also affect the mucous lining (mucosa) of the small intestine, resulting in reduced carbohydrate and protein absorption.
Bacteria have the ability to compete for available nourishment. Furthermore, chemicals created by the bacterial breakdown of stationary food might cause diarrhea. These bacterial overgrowth effects result in diarrhea, malnutrition, and weight loss.
- Vitamin deficiency: Because of insufficient fat absorption, your body is unable to fully absorb the fat-soluble vitamins A, D, E, and K. Bacteria in the small intestine generate and consume vitamin B-12, which is required for appropriate nervous system function as well as the generation of blood cells and DNA.
Bacterial overgrowth can cause B-12 deficiency, which can cause weakness, weariness, tingling and numbness in your hands and feet, and, in severe cases, mental confusion. B-12 deficiency can cause irreparable damage to your central nervous system.
- Osteoporosis (weak bones): Damage to your intestine from abnormal bacterial growth causes inadequate calcium absorption over time, which can lead to bone problems like osteoporosis.
- Kidney stones: Kidney stones can form as a result of poor calcium absorption.
HOW IS SIBO DIAGNOSED?
You may have tests to look for bacterial overgrowth in your small intestine, poor fat absorption, or other abnormalities that may be causing or contributing to your symptoms in order to identify small intestinal bacterial overgrowth (SIBO). Typical testing include:
- Breath testing: This noninvasive test detects the quantity of hydrogen or methane you expel after ingesting a glucose-water mixture. A sudden increase in the amount of hydrogen or methane breathed may suggest bacterial overgrowth in your small intestine. Breath testing, while readily available, is less specific than other types of tests for identifying bacterial overgrowth.
- Small intestine aspirate and fluid culture: This is the gold standard test for bacterial overgrowth right now. A long, flexible tube (endoscope) is sent down your neck and across your upper digestive tract to your small intestine to retrieve the fluid sample. A sample of intestinal fluid is taken and analyzed in a laboratory for bacterial growth.
In addition to these tests, your doctor may advise you to have blood tests to check for vitamin deficiency or a stool test to check for fat malabsorption. In some situations, your doctor may recommend imaging tests to look for structural abnormalities of the intestine, such as X-rays, computed tomography (CT) scans, or magnetic resonance imaging (MRI).
WHAT ARE THE TREATMENTS FOR SIBO?
Whenever possible, clinicians treat SIBO by addressing the underlying issue, such as surgically correcting a postoperative loop, stricture, or fistula. However, a loop cannot always be reversed. Treatment in this scenario focuses on treating dietary deficits and eradicating bacterial overgrowth.
Antibiotic treatment
Antibiotics are often used to treat bacterial overgrowth in most persons. Doctors may initiate this treatment if your symptoms and medical history strongly suggest that this is the cause, even if test findings are unclear or no testing is performed. If antibiotic treatment is ineffective, testing may be undertaken.
A short course of antibiotics frequently reduces the amount of aberrant microorganisms dramatically. However, bacteria can reappear after the antibiotic is stopped, so long-term treatment may be required. Some persons with a tiny intestine loop may go for extended periods without having antibiotics, while others may require them on a regular basis.
Doctors may also alternate medications to help avoid bacterial resistance. Antibiotics eliminate the majority of gut microorganisms, both normal and pathological. As a result, antibiotics might cause some of the symptoms they're meant to treat, such as diarrhea. Switching between medicines can assist to avoid this problem.
Nutritional assistance
Correcting nutritional inadequacies is an important element of managing SIBO, especially in patients who have lost a lot of weight. Malnutrition is treatable, but the harm it causes is not always reversible.
These medications may help with vitamin shortages, digestive distress, and weight gain:
- Nutritional supplements: SIBO patients may require intramuscular vitamin B-12 injections, as well as oral vitamins, calcium, and iron supplementation.
- Lactose-free diet: You may lose the capacity to digest milk sugar if your small intestine is damaged (lactose). In that scenario, avoid most lactose-containing goods or utilize lactase preparations to aid in the digestion of milk sugar.
Some people may be able to handle yogurt because the microorganisms employed in the fermentation process naturally break down lactose.