Bacterial Overgrowth
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Introduction
While the GI system has 10x more bacteria than human cells.
Colonic bacterial disaccharidases salvage undigested sugars and allow colonic absorption, producing vitamin K and folate. They also protect against pathogenic bacteria such as C. diff. They also metabolize drugs such as sulfasalazine.
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Causes and Risk Factors
Protective factors against bacterial overgrowth include peristalsis, gastric acid, digestion by proteolytic bacteria, intact ileocecal valves, and the mucosal immune system. Compromising any of these can cause problems.
The most common cause is small intestinal stasis: chron's fistulas, small bowel diverticuli, diabetes (decreased motility) scleroderma.
Communication between the colon and small intestine can cause big problems.
Immunodeficiency
chronic pancreatitis
other
hypochloridia
Pathophysiology
Signs and Symptoms
- history
- physical exam
History
Diagnosis is made looking for etiology and symptoms. Emperic treatment can follow.
Jejeunal aspirates through endoscopy, or breath tests, can be done.
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
Differential Diagnosis
Treatments
The underlying cause needs to be found and treated.
Antibiotics can be given, with anaerobic and aerobic coverage. A single course for 7-10 days can be done, though in some people, regular dosing or rotation through can occur.
nutritional deficiencies
Consequences and Course
B12 malabsorption can occur due to anaerobic bacterial competition. This can result in macrocytic anemia, degeneration of dorsal columns, and dementia.
Fat malabsorption can follow early bile acid deconjugation, resulting in proximal absorption. These decreased bile acids decrease micelles. Steatorrhea and decreased absorption of vitamins ADEK can occur.
Carbohydrate and protein malabsorption.
D-lactic acid and is broken down by L-lactic acid dehydrogenase. This can result in neurological symptoms.
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Additional Resources
Topic Development
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