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Battling the Belly Bugs: Unveiling the Secrets of Small Intestinal Bacterial Overgrowth (SIBO)

Abdominal pain is a very common reason people go to the doctor and more so, to a surgeon. As a general surgeon, I am always looking into how I can help my patients. Sometimes, it will involve some type of surgery to help them. Other times, it will involve further work up and a more medical approach. In this article, I will dive into an undiagnosed condition called SIBO.

Small Intestinal Bacterial Overgrowth: Symptoms, Diagnosis, Workup, and Treatment

Small intestinal bacterial overgrowth (SIBO) is a condition that is characterized by an abnormal increase in the number of bacteria in the small intestine. This can lead to a wide range of gastrointestinal symptoms, including abdominal pain, bloating, flatulence, diarrhea, and malabsorption of nutrients. In this article, we will discuss the symptoms, diagnosis, workup, and treatment of SIBO, with reference to recent scientific research.


The symptoms of SIBO can vary widely, but commonly include abdominal pain, bloating, flatulence, diarrhea, and malabsorption of nutrients. In addition, SIBO has been associated with a wide range of non-specific symptoms, including fatigue, headache, joint pain, and skin problems. These symptoms are thought to be related to the production of bacterial toxins and the immune response to the bacteria in the small intestine.


The diagnosis of SIBO can be challenging, as the symptoms are non-specific and can overlap with other gastrointestinal conditions, such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). There are several tests that can be used to diagnose SIBO, including breath tests, stool tests, and small bowel aspirate cultures.

Breath tests are the most commonly used tests for diagnosing SIBO. The tests involve the patient ingesting a substrate, such as lactulose or glucose, and then measuring the levels of hydrogen and methane gas in the breath. Elevated levels of these gases are indicative of bacterial fermentation in the small intestine.

Stool tests can also be used to diagnose SIBO, as they can detect the presence of bacterial overgrowth in the small intestine. However, stool tests are less commonly used than breath tests, as they are less accurate and can be affected by factors such as transit time and the presence of bacteria in the colon.

Small bowel aspirate cultures involve the insertion of a tube through the nose or mouth and into the small intestine, where a sample of fluid is taken and cultured for bacteria. This test is the gold standard for diagnosing SIBO, but it is invasive and requires specialized equipment and expertise.


In addition to diagnosing SIBO, it is important to identify any underlying factors that may be contributing to the condition. These factors can include impaired gut motility, previous abdominal surgery, and certain medical conditions such as diabetes and Crohn's disease. A thorough workup may include imaging studies, such as small bowel follow-through or magnetic resonance enterography, to evaluate for structural abnormalities or evidence of inflammation.


The treatment for SIBO usually involves the use of antibiotics, probiotics, and dietary modifications. The choice of antibiotic depends on the severity of the condition and the underlying cause of the bacterial overgrowth. Rifaximin, a non-absorbable antibiotic, is the most commonly used antibiotic for SIBO and has been shown to be effective in reducing symptoms in patients with IBS.

Probiotics may also be helpful in managing SIBO symptoms, as they can help to restore a healthy balance of bacteria in the gut. A systematic review and meta-analysis by Ghoshal et al. (2017) found that probiotics were effective in reducing symptoms of SIBO, although further research is needed to confirm their efficacy.

Dietary modifications may also be necessary to manage SIBO symptoms. A low-FODMAP diet, which restricts certain types of carbohydrates that can be fermented by gut bacteria, has been shown to be effective in reducing symptoms in patients with SIBO. Other dietary interventions may include eliminating dairy products, gluten, or other potential triggers.

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