00:01
In this table, we’ll take a look at Vitamin
D dysfunction.
00:03
I said dysfunction because the first column
here is actual Vitamin D deficiency whereas
the second column is referring to pathology
of the receptors for Vitamin D and if anything,
you’d find increase in Vitamin D dysfunction.
00:19
The most common cause of Vitamin D dys-deficiency
in the United States, once again, is chronic
renal failure.
00:25
Do not ever forget this because of the kidney
dysfunction, you have decreased Vitamin D,
decreased calcium, secondary hypoparathyroidism;
the PTH cannot work on the kidney, thus resulting
in hyperphosphatemia, hypocalcemia and may
result in renal osteodystrophy.
00:44
Other cause of Vitamin D deficiency, which
are quite different, would be lack of exposure
to UV-rays, maybe dietary deficiency, rarely,
maybe liver damage.
00:53
And those, you want to keep that separate.
00:58
Whereas if there’s resistance, then any
type of resistance pathology, such as your
diabetes haemolytis type 2, such as androgen-androgen
insensitivity syndrome, such as your nephrogenic
diabetes insipidus and in this case, we have
Vitamin D and organ resistance.
01:12
You can expect the proximal hormone to then
be elevated; no exception here, we have an
increase in Vitamin D.
01:22
Whenever there is Vitamin D dysfunction, you
can expect the calcium to be decreased; urine
calcium, in fact, could be increased.
01:33
We have plasma phosphate being decreased,
urine phosphate being increased.
01:43
The reason for all of this is because there
isn’t enough Vitamin D. So, therefore, it’s
being wasted away through the urine depleting
it in your plasma.
01:56
Osteomalacia, if rickets is to a child, osteomalacia
is to an adult.
02:03
So, there is no bowing of the leg, fontal
bossing, rachitic rosary, the pectus carinatum
and such; asymmetrical protrusion of the sternum.
02:13
Osteomalacia is in adult.
02:14
And here, if anything, we call the osteoid
seam referring to that, once again, the epiphyseal
plate which has been mineralized, remember
that.
02:23
Osteomalacia, we’re talking about adults,
mineralization is taking place, most common
cause again chronic renal failure.
02:30
Usually, calcium phosphate deficiency due
to dietary, malabsorption, decreased Vitamin
D synthesis, that would be something like
your kidney damage.
02:39
Clinical symptoms: osteomalacia, hypocalcaemia,
fatigue, diffused bone pain and muscle weakness
is what you’re paying attention to in osteomalacia
patient, adult.
02:54
Often low or low-normal calcium, hypophosphatemia.
02:59
Now, be careful here, the reason we call this
hypophosphatemia, could this ever be caused
by chronic renal failure?
No.
03:12
In chronic renal failure, it might result
in osteomalacia, but the phosphate will be
elevated.
03:22
Any other cause of Vitamin D deficiency, you
can expect there to be secondary hyperparathyroidism
and wasting away all the phosphate.
03:32
Mildly elevated alkaline phosphatase, once
again, because of that secondary hypoparathyroidism
which may then work upon that bone.
03:39
So, this first bullet point will be dealing
with every type of osteomalacia due to lack
of sun exposures, so on and so forth except
for chronic renal failure.
03:48
That was a topic that we covered in great
detail when we did nephrology.
03:53
Confirmed by bone biopsy, the tetracycline
labeling showing undermineralized bone.
04:03
Both osteomalacia and rickets, you have a
problem with mineralization.
04:06
In rickets, however, as a child, all kinds
of issues that we discussed, osteomalacia,
osteoid seam will be widened because of lack
of mineralization.
04:18
Treat by repleting calcium and Vitamin D,
depending as to what the cause was.
04:23
Often require quite a bit, it’s called ergocalciferol.
04:27
Here’s my dosage and timeline.