Today we talked about an elderly man with recent ACS on DAPT, HFrEF 25%, and h/o colonic angiodysplasia induced LGIB who presented with acute onset of obscure overt upper GI bleed, found to have a dieulafoy lesion on repeat EGD!
- Overt GI bleed refers to bleeding that is clinically evident (i.e. hematemesis, hematochezia, melena, etc.)
- Occult GI bleed refers to slow bleed that primarily manifests as iron deficiency anemia and/or positive guaiac stool.
- Obscure GI bleed refers to evident GI bleed without a clear source on EGD/colo.
- Most common cause is angiodysplasia
- First step in the work up of obscure GI bleed is to repeat EGD/colo. Up to 50% of cases are successfully diagnosed this way.
- Tachycardia is the first sign of blood loss and suggests up to 30% total blood volume loss. Hypotension develops once blood loss >30%.
- For people at high risk of thromboembolic events requiring anticoagulation, restart anticoagulation/antiplatelet therapy as soon as possible after acute bleeding is resolved (prior to discharge!). Be sure to discuss risk of rebleeding with endoscopist prior to restarting these agents.
Obscure GI bleed
The following is a simplified breakdown of diagnoses to consider in obscure GI bleed. Keep in mind that many diagnoses can present as overt or occult GI bleed. We have listed them here under the more common way in which they present:
- Remember that NSAID induced ulcers can occur anywhere in the GI tract as far distally as the splenic flexure!
- Angiodyplasia is the most common cause of obscure GI bleed.
- Repeat EGD/colo is the first step. Up to 50% of the cases are diagnosed in this way.
- If EGD/colo inconclusive, then
- Obscure active bleed
- Tagged RBC scan: technetium 99m-labeled RBC or sulfur colloid nuclear scans. Can detect slow bleeds with accuracy varying from 24-91%. They can only identify a general area where bleeding is occurring (not accurate) and a follow up separate intervention is indicated if a source is identified.
- Angiography: Can identify faster bleeds, more effective at localizing bleed, but less sensitive than tagged RBC (27-77%). Allows intervention at the same time.
- Enteroscopy: push, single/double balloon enteroscopy are sensitive (up to 80%) and allow for intervention but are operator dependent and may not always be available
- Intraoperative endoscopy: laparotomy or laparoscopy (sensitivity 58-80%). Last resort.
- Obscure occult bleed
- Capsule endoscopy: allows for imaging of the small bowel and can has a high sensitivity (83%). May be difficult to localize lesion based on imaged. Not a good tool in active bleed.
- Enteroscopy as noted above
- Obscure active bleed
- Treat the underlying etiology!
- In the case of dieulafoy lesions, treatment with electrocautery, hemoclips, argon plasma coagulation, injection therapy, or a combination is effective.
- For people with DAPT or on anticoagulation with warfarin, the current recommendation is to start these agents as soon as hemostasis is achieved. The decision on when to start depends on the type of lesion, risk of bleed (based on edoscopist’s opinion), and risk of thromboembolic event (based on this cohort study and this meta-analysis).
Hemodynamics in GI bleed:
- Tachycardia is the first vital sign abnormality in GI bleed and is noted with 15-30% blood volume loss. With lower amounts of blood loss, tachycardia may be present upon standing. If a patient is tachycardic while laying supine, blood loss is closer to 30%.
- Blood loss >30% total body volume results in hypotension. This typically begins as a widening of pulse pressure (drop in diastolic BP) followed by a drop in systolic BP.