hey everyone this is part two in the
vitamin d deficiency series so
in the last lesson we talked about the
sources of vitamin d
why we need vitamin d the absorption and
metabolism of vitamin d
and finally a category of causes of
vitamin d
this lesson we're going to focus on
clinical features of vitamin d how it's
diagnosed and how it's treated
and before we get into the clinical
features of vitamin d deficiency it's
important to note that a majority of
patients with vitamin d deficiency
are asymptomatic they don't experience
any acute
symptoms now i say that specifically
acute symptoms as
we will see there can be some chronic
findings later but for the most part the
majority of patients with vitamin d
deficiency don't experience any acute
symptoms
and if they are symptomatic a lot of it
has to do with
issues with low calcium levels so
hypocalcemia low calcium levels in the
blood
and in some cases we may see signs and
symptoms of hypocalcemia including
perioral tingling so a tingling
sensation around the mouth
chavostek sign which occurs when the
facial nerve is continuously tapped and
the facial nerve doesn't relax
properly and another sign we could see
with hypocalcemia is truso sign
which occurs when a blood pressure cough
is inflated on someone's arm
and that patient has a carpal pedal
spasm
so if you want more information on those
signs and symptoms please check out my
lessons on those topics but for the most
part we're going to talk about
what happens after hypocalcemia so
what happens is that a hypocalcemic
state
leads to an upregulation of the activity
of the parathyroid glands leading to a
secondary hyperparathyroidism
so because there's not enough vitamin d
or calcitriol around to absorb
calcium from the gastrointestinal system
we get
low levels of calcium and calcium
actually prevents
the release of parathyroid hormone so if
we have low levels of calcium
this can lead to an upregulation of
parathyroid hormone release
and this is secondary
hyperparathyroidism so again
this is an entire other topic for
another lesson i'm just briefly talking
about it here
secondary hyperparathyroidism this
increase in parathyroid
hormone leads to the reabsorption of
calcium
and phosphate from the bone that is what
parathyroid hormone does it also does
other functions on the kidneys as well
but right now we're just going to focus
on the bone
so it helps to dissolve bone and release
calcium and phosphate
so because the body is low in calcium
parathyroid hormone goes to the bone
and releases calcium from the bone so
you get bone
reabsorption but what this does is it
causes bone pain
can cause allergies so muscle aches can
lead to arthralgias so
joint aches can cause fasciculation so
muscle twitching
and it can cause weakness so again this
is a very brief overview of
hyperparathyroidism i'll have another
lesson in the future on this topic
specifically
some other clinical features have to do
with bone development and maintenance so
we talked about
hyperparathyroidism causing bone
resorption
well that can cause problems we can get
osteomalacia so softening of bone
we can see this in children in adults if
there's vitamin d deficiency in
children where they're not able to
actually
develop and form their bones properly we
can get rickets and this again occurs in
children and these topics
by themselves are complex and require
their own lessons so i'll talk about
these topics in
future lessons and overall because we're
getting a lot of bone resorption
we get decreased bone mineralization and
that can cause other problems as well
these include osteopenia
and osteoporosis so here is osteoporosis
we see a normal bone and then we see it
becoming very perotic
so it becomes weaker and there's an
increased risk of fractures so it's
increased risk of falls
and increased risk of fractures and
oftentimes these findings can be
evidence for chronic
subclinical vitamin d deficiency so
subclinical vitamin d deficiency really
means that
they have vitamin d deficiency and they
could be having it for a long time but
they're not really having acute
symptoms from it but all the while their
bones are kind of getting weaker
they're having decreased bone
mineralization and then eventually they
end up having issues with
bone health so again can be
evidence that there's been some chronic
ongoing subclinical vitamin d deficiency
and some other clinical features of
vitamin d deficiency include
immunological dysregulation
so it's been shown that vitamin d
deficiency is associated with an
increased risk of various infectious
diseases
and in particular acute respiratory
tract infections seem to occur
more frequently in those with vitamin d
deficiency i won't talk about all the
details here in this slide but if you
want more information please check out
my lesson on
the topic of vitamin d deficiency in the
immune system
but nonetheless it has been shown that
patients who are
vitamin d deficient are at an increased
risk of certain
infectious diseases one of those is
tuberculosis another one is influenza
and another one is bacterial vaginosis
so these are some of the infections that
patients can be at an increased risk for
if they
have vitamin d deficiency and some other
clinical features of vitamin d
deficiency
can occur in children and these include
developmental delay
lethargy and irritability and then
there's increasing evidence that vitamin
d deficiency is associated with an
increased risk of depression
obesity diabetes heart disease and some
types of cancer
so there's a lot of research to be done
with regards to vitamin d deficiency and
some of these other
conditions as well so we do see that
there's evidence for
an association between vitamin d
deficiency and an increased risk of
depression
obesity diabetes heart disease and
cancer so as you can see vitamin d
deficiency is associated with many
different conditions and each of these
conditions requires its own
topic of discussion so in future lessons
i'm going to delve into
each of these conditions with regards to
vitamin d deficiency
so how is vitamin d deficiency diagnosed
vitamin d deficiency is diagnosed by
looking at 25 hydroxy vitamin d
levels so we're going to talk about what
the cutoffs are for the diagnosis
clinicians can also look at parathyroid
levels to assess for secondary
hyperparathyroidism as well
so the levels for diagnosing vitamin d
deficiency
are the following and there is some
debate as to the optimum levels of
vitamin d but these are the numbers
that have been stated so mild deficiency
of vitamin d
is when 25 hydroxy vitamin d levels are
less than 20
or less than 30 some sources say 30
nanograms per milliliter
moderate deficiency is when 25 hydroxy
vitamin d levels are less than 10
nanograms per milliliter
and severe deficiencies when 25 hydroxy
vitamin d
levels are less than 5 nanograms per
milliliter
so these are the numbers that classify
mild moderate and severe vitamin d
deficiency so how is vitamin d
deficiency treated
so it's all about replacing vitamin d
but you might be asking which one
should be used vitamin d3 or vitamin d2
so vitamin d3 has actually been shown
to replete levels of vitamin d quicker
than vitamin d2 so vitamin d3 is
most often used and the amount of
supplementation of vitamin d
differs depending on age and risk
factors so we're going to briefly talk
about this but it is a very complicated
topic
and i suggest checking out that
reference in the description below
before i get into how much to give to
replete
vitamin d levels once levels are normal
the maintenance dose in patients who are
considered lower risk and i'll talk
about this a little bit more here as
well
is one thousand to two thousand
international units per day so
we talked about minimum levels before of
about 800 but
if an individual has had vitamin d
deficiency and there's really no other
risk factors
that we can see or note usually
the maintenance dose is one thousand two
thousand international units per day
and i mentioned this with regards to
lower risk individuals because
the maintenance dose is likely higher in
high risk individuals
so these maintenance doses can be as
high as three thousand to four thousand
international units per day
for individuals who are particularly at
higher risk and some of these
individuals can include darker skin
individuals and people that are
overweight are obese
when an individual is deficient if they
have a vitamin d deficiency
oftentimes it is stated that six
thousand international units per day be
given for eight weeks
followed by a maintenance dose once
vitamin d levels reach normal levels of
at least 30 nanograms per milliliter so
6 000 international units per day for 8
weeks and then
once vitamin d levels have been reached
to normal levels the maintenance dose so
again maintenance dose differs
between lower risk and higher risk
individuals and then you might find that
in some cases of high high-risk
individuals who are deficient they may
need
even higher levels for a shorter period
of time too so again very complicated
topic
and there's some special circumstances
if vitamin d deficiency has
led to severe hypocalcemia where
patients are having
symptoms of hypocalcemia iv calcium is
given
if there's severe osteopenia or
osteoporosis bisphosphonates are also
given
and in patients who have liver disease
or
issues actually metabolizing fat
calcidil
is given so 25 hydroxy vitamin d not
ergocalciferol or cholecalciferol
because
they might not be able to add that first
hydroxyl group
in the liver or they might not be able
to absorb it
at all so calcidal is given for those
with liver disease or issues with fat
metabolism
and if there's persistent issues with
vitamin d deficiency even after
giving supplementation calcitriol is
often given
so you essentially bypass those two
modification steps in the liver and in
the kidneys so calcitriol
is the one that is given if there is
essentially refractory
vitamin d deficiency so again this is a
very complicated topic it's very
complicated to go through i hope you
found this
lesson helpful and informative if you
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thank you so much for watching and i
hope to see you next time