welcome to another MedCram lecture we're going to talk about a case which
is gonna illustrate the need for understanding laboratory data okay so
let's get started we have a 60 year old Caucasian male who presents with
diarrhea and hypotension fever chills and dizziness
vital signs his temperature is 38.3 his pulse is 135 his respirations are 30 and
his blood pressure is 85 over 55 on physical examination he is alert and
oriented times 1 to 2 he is lethargic on head ears eyes nose and throat
examination it is clear but his mucous membranes aren't dry on
cardiovascular exam he is tachycardic and on lung exam
he has clear to auscultation bilateral lung fields on abdominal exam it is
tender to the left lower quadrant but no rebound and on extremity exam
there is no clubbing cyanosis or edema laboratory values look like this his
white blood cell count is 55.0 his hemoglobin is 16.0 his platelet count is
85 and as haematocrit is 48.0 his chemistry's look like this his sodium is
145 his potassium is 3.0 chloride is 115 his bicarbonate is 13 his be--when is 30
his cratan is 1.5 and his glucose is 200 chest x-ray is clear and the KUB is
non-specific he gets a CT scan of the abdomen and it shows wall thickening in
the sigmoid colon you ask further history and the patient has had a UTI in
the past for which he has gotten antibiotics okay so by this point some
of you would probably already know the diagnosis here this guy just looking at
him there's several things that you can look at you can see that his blood
pressure is low and that his pulse rate is high this is consistent with
hypovolemia but it's also consistent with septic shock and given the fact
that the white blood cell count is definitely elevated would lead you to
that the kind of IV fluids that you would want to give are resuscitative
fluids so that you could expand the volume one appropriate type of IV fluid
be normal saline however there's recent evidence that shows that giving balanced
fluids especially in patients with renal insufficiency will be beneficial and so
another probably more appropriate fluid would be lactated ringers or LR another
one that you could give would be half normal saline with 75 milli equivalents
of sodium bicarbonate so what you're doing here is instead of just giving
pure chloride you're giving lactated ringers or bicarbonate solution okay now
if the map does not increase to greater than 65 then you're gonna probably have
to start some vasopressors through a central line and resuscitate this
patient now looking at this haemoglobin here I can see clearly that this is an
elevated hemoglobin for somebody who is so sick and this is probably showing
chemo concentration here the low platelets are probably a result of
septic shock we could check that out by looking at the pt/inr and PTT to see if
they were elevated and also the fibrinogen level if that was low this is
the hematocrit it's usually gonna be three times that of the hemoglobin let's
look at the chemistry here we've got the sodium and the potassium the chloride
the bicarbonate the B UN and the creatinine and then we have the glucose
so the first thing that you want to look at is the sodium and the potassium here
I can see that the sodium is elevated that usually means that there's some
amount of dehydration which goes along with what we're seeing here already this
very high white blood cell count by the way is usually indicative of just a few
things and specifically because we're dealing with sigmoid a colonic wall
thickening the big thing that you have to think about there is c-diff c-diff
colitis and there are only a few antibiotics that can treat that also
with relation to the history of antibiotics in the past that also puts
it together so why would the patient have a low potassium because the patient
has diarrhea and that's going to get rid of a lot of potassium it's also going to
get rid of some water and volume that could be the reason why the patient is
hyponatremic or on the border of being hyper neat reaming clearly here the
patient has a low bicarbonate which is indicative of a metabolic acidosis and
whenever you consider or entertain the possibility that the patient has a
metabolic acidosis you need to calculate the anion gap so we add here 150 into 13
and we come up to 128 and 128 from 145 is an anion gap of 18 so that's an
elevated anion gap what could that be from well I can tell you that the
patient had a lactic acid level of approximately 5 and that could explain
why the patient's lactic acid level and anion gap therefore is elevated but if
we add the lactic acid level to the bicarbonate and say okay let's say that
the lactic acid went away and went to normal this would only raise our bicarb
to that of 18 which means that it's well still below 24 which is where it should
be and that means that we have a non anion gap metabolic acidosis as well
which is probably related to the diarrhea so I think what we have here
based in the labs and the radiographic findings and the vital signs is somebody
clearly in septic shock from seed of colitis who is very dehydrated he needs
brisk resuscitation you want to avoid normal saline I think in this case
because that's simple exacerbate your non anion gap metabolic
acidosis so giving some sort of lactated ringers or bicarbonate it's going to be
probably advisable that's going to help your resuscitative events it's probably
going to help out with your kidney function you're gonna have to make sure
with that resuscitative efforts that you're aggressively replacing potassium
because the potassium is only going to fall once you correct the acidosis and
you resuscitate the patient correctly now a lot of these things that we've
just discussed about if you are completely lost here there are a number
of lectures that I want to direct your attention to many of which are on our
med cram a channel at YouTube but also I want to direct you to med cram comm and
we actually have a new series which gets into the idea of understanding what a
CBC can tell you and all the different possibilities so look for that also we
have a series on vasopressors that talks about which vasopressor you would want
to add and also regarding interpretation of chest x-rays in addition we also talk
about septic shock and that's clearly something that this patient has so we
also talk about tackling every single type of acid based disorder in our acid
base series where we talk about laughing acidosis we talk about figuring out the
anion gap and how to calculate all of the different types of acid based
disorders that you can have in a patient well with that thank you for joining us
you