Editing Blind loop syndrome


''Rare condition caused by bacterial overgrowth in stagnant areas of the small bowel''

== Aetiology (areas where it can occur) ==

* Stricture
* Stenosis
* Fistulas
* Diverticula

== Pathophysiology ==

* Usual mechanisms to limit bacterial populations:
** Continuous flow of luminal content
** Gastric acidity
** Local effects of immunoglobulins
* Impact of overgrowth
** Bile salt deconjugation and dihydroxylation in proximal small bowel, rendering them ineffective, and allowing unabsorbed fats into the colon
** Hypocalcaemia
** Anaerobic bacteria take up B12
** Bacteria use carbohydrates and protein
** Bacteria damage mucosa, further impairing absorption

== Investigation ==

* Bacterial overgrowth can be confirmed by cultures obtained through an intestinal tube, or by breath tests (14-C-xylose or 14-C-chloyglycine)
* Bacterial overgrowth occurs and compete for dietary B12, producing a systemic deficiency of B12 and megaloblastic anaemia
* Schilling test (57-Co-labelled vitamin B12 absorption study) - will show minimal (0-6%) urinary excretion of vitamin B12, as it's not being absorbed. This pattern of excretion is not altered by addition of intrinsic factor, but broad-spectrum antibiotics should return it to normal.

== Treatment ==

* Parenteral B12
* Broad-spectrum antibiotics
** A single course of metronidazole or rifamixin is usually sufficient to treat for several months
* Surgical correction of underlying cause where possible

[[Category:Small bowel]]