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continue our discussion of concentration
of urine
up until now we looked at adh looked at
its control
and then went into sadh in great detail
now we take a look at diabetes insipidus
the opposite of but nonetheless
an important differential to keep in
mind when you have plasma
and urine osmotility at hand
so we have nephrogenic diabetes
insipidus now what we will do here
ladies and gentlemen is under renal
or nephrology we will strictly only be
managing nephrogenic diabetes insipidus
i want to make sure that we're clear
because there's no important piece of
information that is
left out in your lecture series with me
the centro diabetes insipidus will be
dealing with that in endocrinology is
that clear
so here let's just keep things relevant
and all that i will bring to your
attention
is the pathology of diabetes insipidus
nephrogenic
in the category of nephrology with that
said
let's continue and before we move on
though let's talk about the basic
definition and
predict as to what's going to happen in
our patient with nephrogenic diabetes
insipidus
nephrogenic that means that there's a
problem in the kidney
in which adh is not working properly
now just to make sure we're clear if you
have a patient
that has sadh maybe perhaps secondary
too
small cell lung cancer we talked about
that in great detail
then you would purposely induce
nephrogenic diabetes insipidus by giving
a drug such as
a democracy so that you can deal with
sadh
however now we come to the actual
primary disease of
nephrogenic diabetes insipidus there's
not going to be your
v2 receptors working properly you are
not going to be able to properly
reabsorb your water
if that's the case you're going to
create massive
and diluted urine this clearance of that
water
which is free will be absolutely
positive
remember if clearance of water is zero
and that's where all i really focused
upon
if clearance of your water was zero it's
the fact that you're producing
urine that is obligated meaning with
sodium
it's not free of solute but
if you're producing lots of diluted
urine
and you're clearing this then understand
there's going to be a lot more free
water
than there's going to be solute free or
excuse me
a company with solute so there's going
to be a lot more free water thus
the clearance of water here is going to
be positive
all that is what we predicted let's
continue
plasma osmolarity increases
plasma osmolarity increases are you
seeing it
you're losing diluted urine thus plasma
osmolarity increases
it stimulates supposed to pituitary to
do what to produce even more adh
but obviously it's not going to do
anything
so this is a condition in which and
let's now draw some parallels
if the receptors aren't working give me
some pathologies in which the receptors
aren't working properly
pth receptors aren't working properly
what's that diagnosis that's
pseudohypoparathyroidism
your testosterone receptors aren't
working properly give me that diagnosis
androgen and sensitivity syndrome your
insulin receptors aren't working
properly give me that diagnosis
diabetes mellitus type 2 here we have
the receptors for adh not working
properly
why am i bringing all these up
technically speaking
clinically each one of those situations
that i just gave you
including this one where we have adh
receptors that v2 receptors aren't
working
the pth receptors and
pseudo-parathyroidism not working
the receptors are testosterone not
working the insulin receptor is not
working
clinically at some point in time in that
disease course
of those differentials that i gave you
you would always expect that
hormone level to be what
high because the receptors aren't
working
you're going to get feedback mechanism
where oh my goodness i want i want i
want i want more hormone
want more hormone want more hormone
hence in pseudopythagorasm you'll find
increased pth
hence in antigen and sensitivity
syndrome you find increase in
testosterone
you could listen you could in diabetes
type two
with an obese patient with insulin
resistance
actually have increase in insulin and
you will and
you will hence you'll have many of the
pathologic courses
or sequelae that we see in diabetes type
2.
here we're going gonna have too much adh
are you drawing the parallels now i
cannot talk about this
in good faith without telling you that
there are other diseases that behave the
same way
let's continue so circulating adh levels
now
you can see confidently and understand
as to why
it's elevated but who's not responding
the principal cells
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you