Continue our discussion of
chemical dipsticks in urinalysis
Let us now take a look at blood
Now up into this point in part
one of our lecture series
we went ahead and talked
about in great detail
urobilinogen and bilirubin
and the difference
between those types
it's important that you get those down
now we'll go into blood as being
part of our analysis in the urine
detects RBCs, hemoglobin, myoglobin.
What are the differences?
Well say that you end up having RBC that
has to squeeze through the glomerulus
Yes, I'm being dramatic.
As an RBC squeezes
through the glomerulus,
is it possible that it might
then become disfigured?
You know what kind of RBC that's called?
I just kind of gave it away
It's called dysmorphic.
What's morphology mean?
What's dys mean?
Messing it up.
So a dysmorphic RBC would be an RBC that
would be more of a glomerular origin.
Are we clear?
So type of RBC that you see becomes
important and relevant for us.
What if you find just RBCs
in general in the urine?
That could be anything.
What does that mean?
That means that RBC could be
from damage of your tubule,
not from the glomerulus.
or it could be damage done
in the urinary bladder
maybe due to cystitis
Do you see the difference now?
So what you wanna do is
your urinary bladder from your
kidney, and even within the kidney
separate your tubules
from your glomerulus
Hemoglobin and myoglobin; Remember
myoglobin, if you find this in your urine
will then give you your
pinkish red myoglobinuria
and the way that this occured
was due to crush injury
and then I gave you hemoglobinuria as
well, and that would be red remember,
thaat patient woke up in the morning and,
"Aah, it's a red urine"
panicked a little bit.
Wake up in the morning,
or maybe after exercise.
those are acidotic environments
that the patient was in prior
either during sleep
or during exercise
Acidotic- respiratory or
And in doing this process, in a patient
in paroxysmal nocturnal hemoglobinuria
end up having red urine.
hematuria; renal stones
being an example.
So, Dr. Raj you just told me about PNH.
Yeah, I did.
What do you think PNH is?
Paroxysmal Nocturnal Hemoglobinuria.
Not that I'm asking what
the abbreviation mean
I'm asking you what category
of hemolysis is it?
Is it intra- or extravascular?
If it's hemoglobinuria, it
has to be intravascular, is that clear?
Dr. Raj, what about extravascular?
Remember that sickle
I met a sickle cell patient.
Sickle cell disease,
homozygous- acute chest pain
There was issues with hands, dactylitis
- that's extravascular hemolysis.
What was significant in that patient?
It was jaundice, it's significant.
Hematology's interesting, isn't it?
Myoglubinuria, crush injury.
What else might you find with
use common sense.
If your muscle's actually
being broken down.
Skeletal muscle, shall we say got
into an accident, a crush injury.
What else would you expect to
find apart from myoglobinuria?
Isn't creatine kinase a component
of your skeletal muscle?
Of course. So you have increased
serum creatine kinase.
Hope that's clear, let's move on.
Nitrites you'll find
this to be interesting
Many times in microbiology, they
end up talking about this but
to differentiate pathologically what
kind of urinary tract infection
your patient is suffering from,
you'll find this to be neat.
Nitrites is my topic.
It detects nitrites produced
by nitrate-reducing uropathogens
This include your E.coli
How important is that?
One of the most common causes
of urinary tract infection
Something like E. coli,
gram negative organism
And what might you
be looking for here?
Okay, now the test is
sensitive and specific
respectively, 30 and 90 percent,
specific at 90 percent
and requires, this is where
its gets really interesting,
requires approximately 4 hours
for nitrate-reducing your pathogens
to convert the nitrate into nitrite.
Now, the reason that I'm being so
dramatic here about the names,
is because, don't confuse
this with "esterase", right?
Even though E.coli has an "E", do
not equate it to esterase.
This is nitrite.
In patients who had urinary tract
infections frequently have what?
increased frequency of urination, which
explains the test has poor sensitivity.
You see it has to how
wonderful this is explained
in terms of why sensiitivity
is a measly 30 percent
but specificity is
a high 90 percent.
Think about your patient, urinary
tract infection, what are they doing?
"Hey doc, I have a burning sensation"
most likely a female
And what is she doing? She's going
to the bathroom so she can urinate
Do you think that perhaps that she's actually
evacuating the organism during this time
and not allowing for sufficient amount of
time for the conversion to take place?
So sensitivity could be quite low
But if your patient is presenting as such
and you know this about the pathogenesis
then you have properly
managed your patient.
Now this versus esterase.
that mean to you?
What's leukocyte mean? WBCs.
What type of WBC might you find
most notably with bacteria?
If it's esterase, then it detects
the esterase in your neutrophil
Well, you kinda know about neutrophil in
pulmonology, or respiratory pathology
and the reason I say that is because
neutrophil up in your lungs,
when it comes to, let's say take
care of antigens in great abundance,
Something like maybe smoking,
What's that enzyme that neutrophil
releases there in the lung?
At some point, if you release
too much elastase in the lung,
What's your diagnosis?
This is neutrophil dying where?
In the urinary tract.
What enzyme is it releasing?
80 percent sensitivity in infections.
Examples, now be careful.
Urethritis, I want you to go
anatomically from distal to proximal,
Urethra is infected. Urethritis,
are you going to find neutrophils?
Cystitis, infection where?
Are you gonna find
neutrophils and esterase?
Pyelonephritis, go more proximal.
Kidney infection now
abscess formation, flank
pain, back here in the flank
and with pyelonpehritis,
Dr. Raj what the
heck was your point?
My point is this,
WBC cast are different from
neutrophils, is that clear?
What do you mean?
Casts are only coming from the kidney,
Cast will never be found
in the urethritis.
Cast will never be
found with cystitis.
Cast are almost always
found with pyelonephritis.
In all three, would you find cells?
If with bacteria, what kind of cells?
What is this test?
Sterile pyuria, neutrophils present
but negative standard urine culture
Now one big organism, such as
Chlamydia trachomatis urethritis,
TB and drug induced
Now all of these in which
you would find neutrophil
but you come back to be
negative for culture.
Two big ones here, chlamydia and the other
one would be interstitial nephritis
Further discussion we'll have with
interstitial neohritis in other lectures.