In this table, we’ll take a look at Vitamin
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.
The most common cause of Vitamin D dys-deficiency
in the United States, once again, is chronic
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.
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.
And those, you want to keep that separate.
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.
You can expect the proximal hormone to then
be elevated; no exception here, we have an
increase in Vitamin D.
Whenever there is Vitamin D dysfunction, you
can expect the calcium to be decreased; urine
calcium, in fact, could be increased.
We have plasma phosphate being decreased,
urine phosphate being increased.
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.
Osteomalacia, if rickets is to a child, osteomalacia
is to an adult.
So, there is no bowing of the leg, fontal
bossing, rachitic rosary, the pectus carinatum
and such; asymmetrical protrusion of the sternum.
Osteomalacia is in adult.
And here, if anything, we call the osteoid
seam referring to that, once again, the epiphyseal
plate which has been mineralized, remember
Osteomalacia, we’re talking about adults,
mineralization is taking place, most common
cause again chronic renal failure.
Usually, calcium phosphate deficiency due
to dietary, malabsorption, decreased Vitamin
D synthesis, that would be something like
your kidney damage.
Clinical symptoms: osteomalacia, hypocalcaemia,
fatigue, diffused bone pain and muscle weakness
is what you’re paying attention to in osteomalacia
Often low or low-normal calcium, hypophosphatemia.
Now, be careful here, the reason we call this
hypophosphatemia, could this ever be caused
by chronic renal failure?
In chronic renal failure, it might result
in osteomalacia, but the phosphate will be
Any other cause of Vitamin D deficiency, you
can expect there to be secondary hyperparathyroidism
and wasting away all the phosphate.
Mildly elevated alkaline phosphatase, once
again, because of that secondary hypoparathyroidism
which may then work upon that bone.
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.
That was a topic that we covered in great
detail when we did nephrology.
Confirmed by bone biopsy, the tetracycline
labeling showing undermineralized bone.
Both osteomalacia and rickets, you have a
problem with mineralization.
In rickets, however, as a child, all kinds
of issues that we discussed, osteomalacia,
osteoid seam will be widened because of lack
Treat by repleting calcium and Vitamin D,
depending as to what the cause was.
Often require quite a bit, it’s called ergocalciferol.
Here’s my dosage and timeline.