So now, let's talk a little bit more
about gastrointestinal or GI bleeds.
The difference anatomically between an
upper GI bleed and a lower GI bleed
is the cut-off point of
the ligament of Treitz.
This is in the 4th
portion of the duodenum.
So, everything above that is an upper GI bleed
and everything below is a lower GI bleed.
The reason why we care about that is because upper
GI bleeds present differently from lower GI bleeds.
So with an upper GI bleed, patients tend to come in
with melena which is dark or black-colored stools
or they may have hematemesis, which
is the vomiting of bright red blood.
On the other hand, lower GI bleeds
tend to present with hematochezia.
This is when there is bright red blood
that is passed from the rectum.
Keep in mind however, that
a very quick upper GI bleed
may also sometimes present with hematochezia,
if the bleeding is occurring fast enough.
So, when I see a patient complaining
of any one of these symptoms,
I always want to make sure to ask
about these important risk factors.
So, the patient's past medical history.
Have they ever had a GI bleed before?
Do they have a known history of ulcers
or history of infection with H. Pylori?
These are some of the things I want to ask.
You also want to make sure to
ask about their medications.
So do they use NSAIDs frequently?
Are they on any anticoagulants or antiplatelet
agents like aspirin or clopidogrel?
and importantly, do they
take iron supplements?
This is because iron pills can
actually turn the stool a dark color
and may obscure the
clinical picture of a GI bleed.
You also want to ask about
their social history.
So, are they a smoker or
do they use heavy alcohol?
and in their history, you'll want
to get any comorbid conditions
such as cirrhosis, any
renal disease or cancers.
Other associated symptoms such
as dysphagia or difficulty swallowing?
any unintentional weight loss?
Where they vomiting frequently
prior to the episode?
and have they had any other
changes in their bowel habits?
So, that brings us to the
differential diagnosis for GI bleeds.
It is quite a broad differential so we'll break it
down first into upper and then lower GI bleeds.
Your historical risk factors can help you
narrow down your differential diagnosis.
So, if your patient comes in complaining of
bleeding with heavy NSAID use or alcohol use,
your differential might include
gastric or duodenal ulcers
or erosive esophagitis,
gastritis or duodenitis.
If they have a known history of liver disease or
cirrhosis, then your differential should include:
esophageal or gastric varices and
portal hypertensive gastropathy.
The next thing on your differential is
the arteriovenous malformation or AVM.
This is a rare cause of GI bleeding
but should always be on the differential
since it is always a present risk.
Next, if your patient has, describes a history of
frequent vomiting, prior to presenting with bleeding,
then you could suspect
a Mallory-Weiss tear.
And the last thing that should always
be on your differential is cancer.
Now let's move to lower GI bleeds.
In patients who describe a
history of chronic constipation,
you should be more concerned about
diverticulosis and hemorrhoids.
Those who have a long standing history of
diarrhea, along with bloody bowel movements
might be concerned for
inflammatory bowel disease.
Those who describe abdominal pain along with
their bleeding may have ischemic colitis.
Just as with upper GI bleeds, you
should always be concerned for an AVM.
and in the right patient, who just
describes a history of infectious symptoms
along with their bloody bowel movements,
you might think of infectious colitis.
And lastly, cancer as always should be
on your differential for all GI bleeds.
So now let us move to the physical exam.
There are some important physical
exam findings that can help you
stratify whether your
patient is sick or not sick.
So, the first thing to
look at is their heart rate.
If their patient has resting tachycardia,
so a heart rate greater than 90 at rest,
this implies that they have already lost
about less than 15% of their total blood volume.
Keep in mind here though that if
your patient is taking a medication
that can slow down the heart rate like a
beta blocker or a calcium channel blocker,
then this finding may not be present
and you might be falsely reassured.
The next ting you can check
is orthostatic hypotension.
If your patient meets these parameters
in a drop of their blood pressure
from a supine to a standing position,
this indicates they have already lost
greater than 15% of
their total blood volume.
So this is already a concerning finding.
Next, if your patient is already
hypotensive while lying flat,
in general we consider this a
blood pressure less than 90/60,
however, keep in mind that your
patient's baseline blood pressure
may be a bit lower so you always want
to compare to their known baseline.
If they're hypotensive just
lying flat, this indicates to us
that they have already lost greater
than 40% of their total blood volume
and this is one of your sicker patients.
The next thing you wanna do
is a focused abdominal exam.
This can be helpful to look for things like
rebound tenderness, involuntary guarding
or extreme pain when you
palpate the abdomen.
These things can be helpful to
look for signs of peritonitis.
Peritonitis occurs when there's a perforated organ
or the patient has developed bowel ischemia.
And lastly, the most important thing
you should always remember to do
when seeing a patient with a
GI bleed is a rectal exam.
You want to look for either grossly bloody
stool or black colored melanotic stool.
In addition, you can also check for things
like an anal fissure or hemorrhoids
or any masses on the rectum that might help you
focus your differential diagnosis a bit more.
So now let's move to
There are several lab studies that you should always make
sure to get in a patient presenting with a GI bleed.
The first is a complete
blood count or CBC.
Here, you're looking specifically for a
drop in the hemoglobin or low platelets.
Keep in mind here though that a drop in the
hemoglobin may not be immediately apparent
because the loss of whole blood,
after the loss of whole blood,
it takes time for the body to
re-equilibrate and that drop in hemoglobin
may be delayed by about a day or so.
The next thing you wanna check is
your basic metabolic panel or BMP.
You can look specifically here
for a BUN to creatinine ratio.
When the BUN to creatinine
ratio is greater than 30:1,
this has been shown to correlate well
with the presence of an upper GI bleed.
Keep in mind though that this is only helpful
for upper GI bleeds and not lower GI bleeds.
The next thing you can look
at is your liver panel.
Here, you're looking specifically for
signs of impaired liver synthetic dysfunction.
So, in this case, a low
albumin may be helpful.
Next, you always wanna check coagulation
factors to look for any coagulopathy
that might exist for your patient and
make it more difficult to control bleeding.
And the last thing you
could check is a lactate.
Here, if you find an elevated lactate, this
may be a sign that your patient has developed
signs of end organ dysfunction and
needs to be more aggressively resuscitated.
So let's take a brief moment to talk a little bit
about further test you might do for GI bleeds.
There's a test called an FOBT
or fecal occult blood testing.
As a high value care tip, this is not a test that
you should use to look for active GI bleeding.
It has a very poor sensitivity and
specificity for active GI bleeds
and really should only be used in the
screening for colorectal cancer.