Welcome back. Thanks for joining me on this discussion of gastrointestinal bleeding in this section
of general surgery. When we talk about gastrointestinal bleeding and going forward, I’ll just call it
GI bleeding, the source of GI bleeding is potentially the most important both diagnostically
and therapeutically. Classically, it’s been described as an upper or lower bleed. Upper GI bleed
is defined as any GI bleeding proximal to the ligament of Treitz. Just as a reminder, the ligament of Treitz
is a division between the duodenum and the jejunum. Lower GI bleeding is defined as distal
to the ligament of Treitz. This would include most of your small intestines and of course, your colon.
I like to pose a question to you. What are the causes of lower GI bleeding? I’ll give you a second
to think about this. Here are some causes of lower GI bleeding: diverticular disease, remember,
not diverticulitis but diverticulosis; angiodysplasias or malformations of vessels; ischemic
or inflammatory colitis; colon cancer; and actually most commonly probably hemorrhoids.
That’s why one never wants to be embarrassed by not doing a rectal examination
and missing a hemorrhoid and doing extensive workup for the other differential diagnoses.
What are some physical findings of a lower GI bleed or a GI bleed in general? Well, not a whole lot.
Patients typically don’t complain of abdominal pain. They, in fact, present with GI bleeding,
whether they’re vomiting blood or having bloody bowel movements, must do a rectal exam.
Check for hemorrhoids. The presence of very fresh blood on fingers after examination suggests
a very, very distal bleed or alternatively, it’s a very high volume proximal bleed.
Of course, check vital signs.Any patient with hemodynamic instability probably has a very significant
or quick GI bleed. Like I mentioned, generally it’s painless. Laboratory values aren’t likely going to help
very much. Please keep in mind that when your CBC demonstrates a drop in your hemoglobin, hematocrit,
it’s already pretty late in the game. There are some imaging studies that can potentially help us diagnose
a GI bleed. This image on the screen is a tagged RBC scan, tagged nuclear medicine red blood cell scan.
The downside of a tagged RBC scan is it’s difficult to localize more than just the left or the right side.
Localization is incredibly important to surgeons because we want to know what segment of colon
to remove should the need arise. But tagged RBC scans are more sensitive. Meaning, it requires
a slower bleed for detection than some other imaging modalities. Mesenteric angiography
has been the gold standard for localizing bleeding. There are some advantages and disadvantages.
Let’s talk about the advantages of mesenteric angiography first. When you send the patient
to the interventional radiology suite, the radiologist use contrast through the mesenteric vessels.
Not only can they diagnose where it’s bleeding, they can also introduce therapy by coil embolization.
Unlike other diagnostic measures, mesenteric angiography is both diagnostic and potentially therapeutic.
Remember though. After coil embolization, one has to be concerned that the blood supply to the colon
may be compromised. What are some disadvantages of mesenteric angiography?
There is a significant contrast load. That contrast load can cause acute kidney injury.
Remember, prehydrate your patients prior to any angiography. Additionally, mesenteric angiography
is not quite as sensitive as the previously discussed tagged RBC scans. For this reason, for this study
to be accurate or sensitive, it has to involve a more brisk bleed. Endoscopy has become
an essential tool for the diagnosis of particularly upper GI bleeding. The rule is this.
Anybody who comes with hematemesis or suspicion of upper GI bleed must undergo a localizing
procedure such as endoscopy. This is an EGD image of the gastroesophageal junction.
Colonoscopy is another important diagnostic tool. Here’s the caveat. For colonoscopy to be successful,
the colon needs to be clean. It needs to be clean to allow safe maneuvering as well as diagnostic purposes.
In the setting of an emergent, potentially significant GI bleeding, oftentimes the colon does not have
the opportunity to be "prepared". If the patient did not undergo a colon prep, the diagnostic value
of a colonoscopy is significantly reduced. Furthermore, in a torrential GI bleed, the GI doctors
may not be able to see anything even if they can pass the colonoscopy.