An accurate diagnosis: the key to properly treating Irritable Bowel Syndrome and SIBO

Intestine, appendix and digestive system, doctor holding anatomy model for study diagnosis and treatment in hospital.

SIBO and IBS may share clinical symptoms, but they are distinct conditions in terms of their underlying mechanisms and treatment.

Thousands of patients experiencing abdominal pain, bloating, gas and changes in bowel habits have lived with a diagnosis of Irritable Bowel Syndrome (IBS) without achieving complete relief from standard treatments. In many cases, these symptoms may in fact be linked to another, less widely known yet increasingly recognised condition: Small Intestinal Bacterial Overgrowth (SIBO).

“SIBO and IBS may share clinical symptoms, but they are distinct entities in terms of both their underlying mechanisms and their treatment,” explains Dr Gerardo Blanco, Consultant Gastroenterologist at Quirónsalud Torrevieja Hospital. “While IBS is a functional diagnosis, based on symptoms and clinical criteria, SIBO has a specific organic cause: an abnormal overgrowth of bacteria in the small intestine, which disrupts nutrient absorption and intestinal motility.”

The origin of these digestive disorders

Irritable Bowel Syndrome (IBS) is a common digestive disorder that causes symptoms such as abdominal pain, bloating and changes in bowel habits, without any visible structural abnormality to explain them. Its origin is complex and is associated with factors such as altered intestinal motility, increased visceral sensitivity, stress, previous infections and imbalances in the gut microbiota.

In the case of Small Intestinal Bacterial Overgrowth (SIBO), symptoms arise when excessive bacteria accumulate in a part of the intestine where their presence is normally limited. This may occur due to impaired intestinal motility, previous surgery or prolonged use of certain medications. The resulting bacterial proliferation leads to excessive fermentation of food, causing gas, bloating and abdominal discomfort.

Diagnosing SIBO

“SIBO may coexist with other digestive conditions, such as Crohn’s disease or even IBS itself, which makes identification more challenging,” explains Dr Gerardo Blanco, Consultant Gastroenterologist at Quirónsalud Torrevieja Hospital.

Precisely because of the similarity in symptoms, differentiating between these conditions is essential in order to apply the appropriate treatment. In the case of Irritable Bowel Syndrome (IBS), diagnosis is primarily based on clinical assessment of recurrent abdominal pain and altered bowel habits, alongside investigations to rule out other digestive diseases.

By contrast, SIBO requires specific diagnostic tests, most commonly the breath test — a simple, non-invasive technique that detects abnormal bacterial fermentation in the small intestine. In selected cases, more complex and precise investigations may be necessary, such as endoscopic aspiration and culture of small intestinal fluid.

“A correct diagnosis makes all the difference and prevents patients from living for years with poorly controlled symptoms. It should always be carried out under specialist supervision,” emphasises the gastroenterology specialist.

A comprehensive approach for improved quality of life

Dr Blanco stresses the importance of avoiding self-diagnosis and self-medication, a practice that is particularly common when patients seek quick solutions online or via social media. “Management must be personalised, taking into account the patient’s medical history, appropriate diagnostic testing and proper medical care, which may include dietary measures, medication and nutritional follow-up.”

Through accurate identification of the underlying cause of each of these digestive conditions, many patients experience significant improvements in their wellbeing and quality of life — an outcome that both specialists and patients regard very positively.

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