What is sibo

What is SIBO?

Small Intestinal Bacterial Overgrowth (SIBO) is a medical condition in which excessive numbers of bacteria grow in the small intestine. Normally, the small intestine has relatively few bacteria compared to the large intestine (colon). In SIBO, bacteria that typically reside in the large intestine migrate to and proliferate in the small intestine, disrupting normal digestion and nutrient absorption.

Causes and Risk Factors

SIBO develops when the body's natural defenses against bacterial overgrowth fail. Impaired intestinal motility (the ability of the small intestine to move food through) is a primary cause. This can result from Irritable Bowel Syndrome (IBS), diabetes, hypothyroidism, or post-surgery complications. Anatomical abnormalities like strictures or blind loops can trap bacteria. Low stomach acid, medications like proton pump inhibitors, and previous abdominal surgeries also increase SIBO risk. Conditions affecting the immune system can also contribute to bacterial overgrowth.

Symptoms of SIBO

SIBO causes a variety of digestive symptoms that significantly impact quality of life. Common symptoms include bloating and abdominal distension, excessive gas and flatulence, chronic diarrhea or constipation, abdominal pain and cramping, and nutrient malabsorption. Some patients experience fatigue, brain fog, and joint pain. Symptoms typically worsen after eating carbohydrates and improve with fasting, as bacteria feed on undigested carbohydrates.

Diagnosis and Testing

SIBO is diagnosed using breath testing, the gold standard diagnostic method. During a breath test, the patient consumes glucose or lactulose solution. The bacteria in the small intestine ferment these sugars, producing hydrogen and methane gases. These gases are absorbed into the bloodstream and expelled through breath, where they are measured. Elevated levels of hydrogen or methane indicate SIBO. Other diagnostic methods include stool testing and intestinal aspirate cultures, though these are less commonly used.

Treatment Options

Treatment approaches include antibiotic therapy using medications like rifaxomicin, typically lasting 2-4 weeks. Dietary modifications, particularly the low FODMAP diet (low fermentable carbohydrates), help reduce bacterial fermentation and symptom severity. Addressing underlying causes is crucial for long-term management. Probiotics, digestive enzymes, and medications that improve intestinal motility may also be recommended. Recurrence is common, affecting 40-60% of treated patients, requiring long-term management strategies.