What are the symptoms of small intestinal bacterial overgrowth (SIBO)?

Gut bacteria is key to maintaining healthy digestion. A change in the delicate balance of gut bacteria, such as in small intestinal bacterial overgrowth (SIBO), can thus result in associated gastrointestinal symptoms, which may require treatment.

Here to provide an expert insight into SIBO, including causes, symptoms and treatment, is Dr Sebastian Zeki, renowned consultant gastroenterologist based in London.

What is small intestinal bacterial overgrowth (SIBO)?

SIBO, or blind loop syndrome, is a condition that occurs when there are excessive bacteria in the small intestine - particularly, the types of bacteria that would usually be found elsewhere in the gastrointestinal tract.

What are the symptoms of SIBO?

SIBO typically causes abdominal pain and diarrhoea.

Other symptoms may include:

• loss of appetite
• flatulence
• bloating
• an uncomfortable feeling of fullness after eating
• nausea
• constipation

As the bacteria begins to drain away the body’s nutrients, the malabsorption of multivitamins and minerals may cause malnutrition and unintentional weight loss, as well.

What causes SIBO?

Bacteria tends to overgrow when there is slow movement of food and waste material through the gastrointestinal tract. Although the exact reason for this still remains unknown, the overgrowth can also be caused by nerve damage, muscular malformation in the intestine, or pH changes in the small bowel.

In SIBO, the condition can develop due to a health complication after gastrointestinal surgery, or due to underlying anatomical and medical conditions that increase a patient’s risk of developing SIBO.

These conditions include:

• autoimmune disorders, such as coeliac disease, diabetes and scleroderma
• cirrhosis
• inflammatory bowel disease, such as Crohn’s disease
• irritable bowel syndrome
• HIV
• gastroparesis (that disrupts the normal passage of food from the stomach to the small intestine)
• hypothyroidism
• Parkinson’s disease
• viral gastroenteritis

Acid-reducing medications, as well as narcotic medications that slow down the process of digestion, are also contributing factors for the development of SIBO.

How is SIBO diagnosed and treated?

To diagnose SIBO, a specialist will carry out several investigations, such as:

• a physical examination of the abdomen
• a blood test
• a breath test that checks levels of hydrogen and methane (two by-products of bacterial overgrowth)
• a faecal sample

Once a diagnosis is confirmed, treatment for SIBO involves a simple course of antibiotics, and/or changes in diet if necessary.

If you require expert diagnosis and treatment for symptoms of SIBO, do not hesitate to visit Dr Zeki's Top Doctors profile today.