Let’s take a look at what happens here and
I want you to identify some of these patients.
I’m just going to walk you through a couple.
We’ll take a look at primary and secondary
hypoparathyroidism and that is it.
Would you please identify, for me, primary
Okay, on your X-axis, we find calcium and
on your Y-axis, we find PTH.
If you have primary hypoparathyroidism, where’s
In the parathyroids.
And you might have a solitary adenoma, it’s
majority of the time will be a solitary adenoma
in which it is primarily releasing PTH.
Next, with all that PTH being elevated, what
then happens to your calcium levels?
It is also elevated.
So, which letter here only gives you that
Let’s take a look at A. A gives you decreased
calcium and it gives you high PTH.
Is that a possibility in primary hypoparathyroidism?
I-I am asking you to please identify primary
That is not possible with patient A. Patient
A with a low calcium may then cause secondary
hypoparathyroidism, so we’ve identified
Most common cause, renal failure.
Patient B, you find there to be elevated levels
of PTH and you also find elevated levels of
That’s your patient, ladies and gentlemen,
of primary hypoparathyroidism; Patient A secondary
You go as far as that, you will be in good
In this table, we’ll take a look at various
diagnosis of hypercalcemia begin by PTH being
We have primary hyperparathyroidism that we
talked about with the solitary nodule, commonly
seen with MEN 1 with your pan-pancreas; para-hypoparathyroidism;
2a would be primary hypoparathyroidism; major
cancer of the thyroid and pheochromocytoma,
if you remember correctly.
Hypercalcemia, the PTH levels might be normal
or slightly high.
If you find urine and calcium to be depressed
and you find hypercalcemia, this may suggest
familial hypocalcuric hypercalcemia.
Understand the concept first, then if you
wish, take a look at your values here where
we have less than 100 milligrams per day or
urinary calcium to Cr ratio of being less
Otherwise you might be thinking about primary
hyperparathyroidism and also… now, lithium
Lithium may then cause hypercalcemia and also,
do not forget that lithium may then-then cause
damage to your ADH receptors.
If it cause damage to your V2 receptors, then
what do we call this?
We call it diabetes insipidus nephrogenic
So, do not forget about lithium and how it
may then cause hypercalcemia, but then may
also cause diabetes insipidus.
We have PTH low or undetectable, but still
may result in hypercalcemia.
What does this mean?
Parathyroid function is appropriate for the
Further testing, depending on the clinical
So, let’s begin.
You find your PTHrP to be increased, so what
does that mean to you?
Examples, we talked about these squamous cell
cancer of the lung and also referred to renal
cell carcinoma where you find hypercalcemia,
but your PTH levels are low or perhaps even
I mentioned that earlier, make sure that you
confirm that properly here for yourself.
If you find increased levels of 1,25 dihydroxycholecalciferol,
maybe it’s granulomatous disease such as
This may also cause increased levels of calcium
which then causes a feedback mechanism where
it tells a parathyroid to-to-to shut down
or perhaps, there was intoxication of Vitamin
D, hypervitaminosis D syndrome.
Evaluate for thyrotoxicosis; adrenal insufficiency
is important as other differentials for hypercalcemia
causing a shutdown of your PTH.
Consider immobilization as well and evaluate
for bone metastasis.
That’s incredibly important.