Gastorintesintal bleeding

GI bleeding is a commonly encountered diagnosis on GIM. At TWH it is the seventh most common admission diagnosis (2009-2010). Today's case was an elderly patient with microcytic anemia and + FOBT but no signs of bleeding raising the suspicion for gastric/colonic malignancy. The CT can of the abdomen made the diagnosis, but this is not always the case. Because there was no history of obvious bleeding in our patient the approach was slightly changed.

Current nomenclature describes two terms for GI blood loss without an obvious initial source:

1. Occult bleeding - presentation with + FOBT and /or IDA with no visible blood loss
2. Obscure bleeding - bleeding from the GI tract that persists or recurs despite negative endoscopy, colonoscopy and radiologic evaluation. This can be subdivided into occult and overt based on whether there is clinically visible bleeding.

Our patient had a + FOBT, and the question was raised as to false positives with this test. There are several different forms of the test, but we use a guaiac based test which identifies hgb based on a peroxidase reaction. False positives can be caused by certain foods - horseradish, red meat, turnips NOT iron pills, and false negatives caused by vitamin c.

Once a patient is FOBT+, the next question to ask is whether they're iron deficient, where patient with a iron deficiency warrant upper and lower endoscopy. Those without anemia should undergo colonoscopy only.

Options for patients who have obscure bleeding following all endoscopic testing include:

Capsule endoscopy- patient swallows a camera and images are analyzed. This is helpful in identifying the source if the patient is actively bleeding, after two weeks from the bleeding event the yield of identifying the problem is significantly reduced. Unfortunately, capsules endoscopy doesn't allow for therapeutic intervention.

Push enteroscopy- a longer scope is pushed into the small bowel for direct visualization. Angiodysplasia are the most commonly seen lesions when this is successful, which ranges from 3-70% of the time.

Double balloon enteroscopy- a scope which allows for small bowel visualization
Small bowel follow through- patient swallows barium and images examined for lesions

Small bowel enteroclysis- barium injected directly into small bowel ,can be CT/MRI evaluated. Generally felt to be worse than capsule endoscopy.

Nuclear scans- use technetium labelled RBC which looks for source of bleeding, or technetium Meckel scan which illuminates gastric mucosa in the small bowel.

Angiography- useful in acute bleeding, as it can also allow for embolization.

As it was wisely pointed out today, the direction of your investigations should be based on the patients directives, and in our case no further investigations were required.