let's talk about glucose
in order for you to understand your
glucose, we had previous lectures
in which we spent a lot of time with
understanding as to how the kidney
handles this glucose, right?
first and foremost, normally should
you be urinating your glucose?
No. almost all of
it gets reabsorbed.
it should, normally through
your glucose transporters
that we've talked about in great detail when
dealing with proximal convoluted tubule
now, if by chance your
patient has hyperglycemia,
then at some point,
you may then hit
what are you gonna hit first?
what's that term called medically,
where you detect glucose
early on in the urine?
Good, that's called
renal threshold, right?
Not TM - that's transport
maximum; renal threshold
so if you start finding glucose
within the urine, be careful.
we'll not detect fructose
or other sugars.
so when you use these
dipsticks, be careful
glucose could be detected but if your patient
is suffering from fructosuria, and so forth
it won't detect it so
you have to be smart
your patient is exhibiting
issues as cataracts and such,
and then glucose comes
out to be negative,
you're still detecting
symptoms like fructosuria,
you need to use something
else to find it
detects glucose in the
urine as low as 30 mg/dL
do you understand
how low this is?
point is, are you supposed to
have any glucose in the urine?
so you need to find or you need
to have effective dipstick
that finds glucose even
at really low levels
serum glucose plus glucosuria, obviously
we're referring to diabetes mellitus
now normal serum glucose
you understand the difference?
so if you find serum
glucose to be elevated
what's normal glucose?
give it to me
approximately 100, right?
normally, approximately 100
keep it simple right now so
you'd understand the significance
if your serum glucose is elevated,
take a look at the arrow
and you have glucosuria,
what's your diagnosis?
if your serum glucose is normal
but your patient has glucosuria
how about a pregnant lady?
we talked about pregnancy
in great detail
when your pregnant, a female
then her plasma volume increases
up to perhaps even 50
percent in increase
that's a lot of plasma volume that
could be increased potentially
do you remember her renal threshold?
before we move there, well
tell me about a female
and what about her ability to
take in glucose into her tissue
is it impaired? or is it taking up
the glucose in great abundance?
Think before you speak.
the fetus, she's pregnant,
that fetus wants food,
"Mama, feed me"
now you have glucose in
that mother in her plasma
don't you want to
feed that fetus?
so therefore her ability to take up glucose
in her skeletal muscles are impaired
on purpose, physiologically. so that
she can then deliver the glucose
passing through the placental
barrier to the fetus
are we clear?
we'll talk more about this when we talk about
gestational diabetes mellitus won't we?
so normal serum glucose, glucosuria perhaps
you'll be thinking about pregnancy
don't memorize it, understand it
low threshold for glucose
in a pregnant lady
benign glucosuria, low renal
threshold for glucose
let's say genetically speaking, a patient
is just born with a low renal threshold
you understand how important it was
for us to walk through the physiology
so that you'd understand the
concept of renal threshold
what does that mean to you?
the early, early, early signs
of finding glucose in the urine
so what about microalbuminuria
as being a dipstick?
well if you find microalbuminuria
along with glucosuria
you know that this is
more sensitive than
if you use the standard dipstick, you may not
find albumin in your urine at lower levels
but there's a microalbuminuria
dipstick, sensitive at very low levels
microalbuminuria plus glucosuria,
they'll give you information in which
you can then arrive at the proper
diagnosis, here diabetic nephropathy
what if that's ketones that you find?
now before we begin, tell me
simple biochemistry for ketones
breakdown product of
which one of these?
is it protein?
is it carbohydrates?
is it lipid?
Are we clear?
your best example would be
symptom like diabetic acidosis
more likely in which type of
diabetic mellitus patient?
No insulin to begin with
you tell me
insulin responsible for breaking down what?
carbohydrate, protein or is it lipid?
really? yes of course you know this.
insulin responsible for
breaking down carbohydrates
so that you can have
glucose and company, correct?
Now my point is this,
you got through glycolysis
say that you don't have insulin.
Wow, I still need energy.
So if you can't get them from
carbohydrates, who are you turning to?
you're turning to me?
No you turn to lipids.
so you're gonna break down your
lipids and that lipid is gonna do what?
breakdown into ketones.
you've heard of
beta-oxidation, have you not?
of course you have
so if you're weak in beta-oxidation, i'll
quickly take a look at your topic on ketones
so you're breaking down your lipid,
what are some important
ketones that you wanna know?
take a look, now pay attention
so now that you've understood, or
recapped DKA (diabetic ketoacidosis)
worst case scenario: where you're
breaking down ketones in great excess
you have to, cause you're
left with no other choice
and some of these
acetone, acetoacetic acid,
and betahydroxybutyric acid
here it detects acetone, acetoacetic
acid but not betahydroxybutyric acid
why is that so important?
acid is one of those ketones
that you produce as alcohol metabolism
Is that clear?
so now i'm giving you two differentials
for ketones appearing pathologically
number one: diabetic ketoacidosis,
what's the other one? alcohol
now in alcohol, you produce mass
amounts of betahydroxybutyric acid
but this ketone dipstick is not going to measure,
so you're gonna come back negative for ketones
But for Pete's sakes, if
your patient is telling you
that I'm drinking one bottle
of Jack Daniels per day,
are you kidding me? of
course that's alcohol
of course there's alcoholic type
of metabolic acidosis taking place
Nitroprusside in the test system only
reacts with acetoacetic acid and acetone
but not the
so look for your ketone dipstick
being negative even in a patient
who's an alcoholic who you know is producing
ketone such as betahydroxybutyric acid