From the Guidelines
Small intestinal bacterial overgrowth (SIBO) can result from four anatomical abnormalities: intestinal diverticula, intestinal strictures, surgically created blind loops, and fistulas between the small intestine and colon, as these conditions create stagnant areas where bacteria can accumulate and lead to SIBO, ultimately affecting morbidity, mortality, and quality of life by causing malabsorption, bloating, diarrhea, and nutritional deficiencies 1. The body normally prevents SIBO through four physiologic protective mechanisms:
- Gastric acid secretion, which creates an acidic environment hostile to many bacteria
- Intestinal motility, particularly the migrating motor complex that sweeps bacteria through the small intestine during fasting periods
- The ileocecal valve, which prevents backflow of colonic contents into the small intestine
- Secretion of antimicrobial substances including bile acids, pancreatic enzymes, and secretory IgA that inhibit bacterial growth, as noted in the study published in Gut 1. When these protective mechanisms fail due to conditions like achlorhydria, diabetic neuropathy, or surgical alterations, bacterial overgrowth can occur, leading to malabsorption, bloating, diarrhea, and nutritional deficiencies, which can significantly impact the patient's quality of life and increase the risk of morbidity and mortality 1. The most effective approach to preventing SIBO is to maintain the integrity of these protective mechanisms, and when SIBO occurs, treatment typically involves addressing the underlying anatomical abnormality when possible, combined with antibiotic therapy to reduce bacterial load, as recommended in the study published in Clinical Gastroenterology and Hepatology 1. Key considerations in managing SIBO include:
- Identifying and addressing underlying anatomical abnormalities or conditions that may be contributing to SIBO
- Implementing antibiotic therapy to reduce bacterial load and alleviate symptoms
- Providing nutritional support to manage malabsorption and prevent deficiencies, which is crucial in improving the patient's quality of life and reducing the risk of morbidity and mortality 1.
From the Research
Anatomical Abnormalities Leading to SIBO
- Small intestinal obstruction 2
- Diverticula 2
- Fistulae 2
- Surgical blind loop or previous ileo-caecal resections 2