Moving to the glomerular region. Up until
this point, what we have done over and over
again is giving you an overview as far as
laying down the foundation and then we build
upon well. With glomerular diseases,
first and foremost,
think about where you are, you are in the
glomerulus and there are numerous issues or
factors that may then result in glomerular
disease. Let us begin. First and most importantly
at this point, is the fact that your operative
word here is biopsy. So the fact that you
are taking a biopsy specimen based on the
symptoms of your patient. Remember once again.
Do you remember when we did our session with urinalysis?
And with urinalysis, you used information
that you had derived based on the history
that you got from the patient, either through
a clinical vignette or from the attending or
what not, and you put all this together so
that you can arrive at the proper diagnosis.
Well, with the biopsy, there are a couple of
important imaging studies that you will have
to conduct. You can do an H &E stain and with
this, we mean hematoxylin and eosin. And with
this, this then allows us to classify the
type of glomerular disease. This, for the
most part, will be light microscopy. What
does light microscopy mean to you? Well, as
we go to the various diseases, when it is relevant
and pertinent, we will then take a look at
diseases in which it is best to classify them
through light microscopy. Well, let us say
that you don't find exactly as to which you
need to or perhaps there is further investigation
that is warranted and then you are going to
other types of stains and this includes something
like immunofluorescence. This is stain number 2,
upon what? Biopsy. What was the first one?
Light microscopy and we are using H&E stain.
With immunofluorescence, it is the
fact that as the name implies, you are literally
immune, well you are looking for the immuno
particles and you are fluorescing them and
with this particular stain, you probably have
seen the color, that bright green type of
appearance whenever there is immunoglobulins
that are being deposited in your glomerulus.
Identify proteins and such.
The linear pattern is something that it is
part of your immunofluorescence and let us takes
for example you have Goodpasture. From immunology,
you have heard Goodpasture being type II hypersensitivity.
What does that mean to you? It means that
it is an antibody dependent issue, isn't it?
Well when you are antibody dependent, what
does that mean? It means that you are literally
attacking your target. So for example, another
name for Goodpasture would be anti-glomerular
basement membrane antibodies. There are no
complexes here that you are forming. Is that
clear? No complexes. So what are they doing?
These immunoglobulins are then literally attacking
the glomerular basement membrane and so therefore
if you have these immunoglobulins attacking
the basement membrane, therefore, what
kind of pattern would you expect to see on
immunofluorescence? You are going to light
up the glomerular basement membrane in a linear
pattern and as we walk through this and I
give you specificlly a Goodpasture or antiglomerular
basement membrane disease, you will see this
pattern under immunofluorescence. Now, if
that is attacking the glomerular basement
membrane, what if you actually had immune
complexes? For example, we have type III hypersensitivity
that may occur with SLE. We have type III
type hypersensitivity in which what does that
mean even? Remember immunology once again.
It means antigen-antibody complexes. You see
the difference. In Goodpasture discussion above,
what was it? A type II hypersensitivity. What
does that mean? You are attacking the glomerular
basement membrane and type III you have immunofluorescence
here that is then recognizing the immune complexes
of antigen-antibody that is depositing where?
Either under the side of the epithelium. When
do you say epithelium you tell me what side
of the glomerular basement membrane are you
on, if I say epithelium? Good, urine side. Whereas
if I say subendothelial between the basement
membrane and the endothelium, that is the
side of the blood. Is that clear? Now, when
you have such complexes that can be deposited
either underneath the endothelial cell or
maybe perhaps under the epithelial cell what
have you formed? Immune complexes. What kind
of hypersensitivity? Type III. Cannot be detected
by electron microscopy and if it cannot so,
therefore, what do you do? You do an immunoflorescence
in which you find a pattern known as granular.
So the granular would then be a "lumpy-bumpy."
All this means is immune complex deposition.
If by chance you cannot find certain things
under electron microscopy such as your linear
pattern, then you'll have to use your immunofluorescence
to find that linear pattern. But let us say
that you have electron microscopy for the
granular pattern, it recognizes immune
complexes perhaps and you want further confirmation,
then upon immunofluorescence, it is then called
your "lumpy-bumpy". Three major patterns of
imaging that are important based on the type
of pathology that you will get and as we go
through both nephritic and nephrotic, I will
be asking you this question such as does this
weren't require LM, light micrioscopy on H&E?
Number 2, biopsy. Immunofluorescence, based on protein
deposition and is it a linear pattern or granular
pattern? And then the third and final one would
be electron microscopy and we had a previous
discussion where we went into great detail
about electron microscopy where we then identify
the glomerular basement membrane, the epithelial
side and the endothelial side.
Let us now continue.