Small Intestinal Bacterial Overgrowth: Symptoms, Causes, Treatment

Symptoms overlap with irritable bowel syndrome, food intolerance and other absorption disorders. Identifying the cause helps avoid repeated antibiotics without diagnosis or follow-up.

Related reading: Short bowel syndrome as another cause of malabsorption.

Bloating, gas, abdominal discomfort, diarrhea and fullness may occur. More significant malabsorption can cause weight loss, greasy stools and vitamin deficiencies.

Abnormal bowel movement or altered anatomy after surgery, narrowing and certain chronic diseases can allow contents to stagnate. Evaluation looks for these underlying factors.

Some intestinal operations, motility disorders and structural abnormalities increase likelihood. Common symptoms or an uninterpreted test result do not establish the condition.

Assessment combines history, examination and an appropriate breath test when indicated, with nutritional review and consideration of alternatives. Breath tests can mislead and require proper preparation and interpretation.

Treatment may use a selected antibiotic while addressing the cause and nutritional deficiencies. Plans and recurrence vary; no single rifaximin dose, diet or probiotic suits everyone.

Malabsorption can cause weight loss, vitamin deficiency, anemia and bone problems. Symptoms may return if a predisposing cause persists, prompting reassessment.

Manage underlying motility problems and nutrition, and avoid self-directed repeat antibiotics. Restrictive diets should be individualized to reduce symptoms without malnutrition, rather than promise bacterial eradication.