There is a condition known as pesudohypoparathyroidism.
I’ll break this entire diagnosis up for
you so that you clearly see why we call it
false or pseudo and why we call it hypoparathyroidism.
So, why is it a false hypoparathyroidism?
Because the receptors for PTH aren’t working
The particular mutation that you very much
want to keep in place is GNAS mutation.
This GNAS mutation results in decreased receptor
activity for PTH.
In other words, this is PTH resistance.
So, therefore, the reason we call this pseudohypoparathyroidism
is because if there’s PTH resistance, what
is the actual PTH levels?
So, we call this pseudohypoparathyroidism,
but you still have to call this hypoparathyroidism
because if the receptors aren’t working
properly in the distal convoluted tubule,
then how in the world are you expected to
reabsorb your calcium?
So, therefore, there’s hypocalcemia which
is still our topic very much so.
So, the serum PTH will be elevated as you
can expect because the receptors aren’t
working properly and there’s hypocalcemia.
In addition, take a look at the hands of your
patient here, it’s a child.
The child, he or she, is short stature.
So, they’re not growing properly.
In addition, if you take a look at the fourth
and fifth digits, they’re shortened, specifically
the fourth and fifth, and you’ll find that
there’s something called knuckle-knuckle,
dimple-dimple and what that basically means
is the following: your metacarpal phalangeal
joint, which makes up your knuckle, if you
want to go ahead and make a fist, the knuckles
here is your metacarpal phalangeal joint.
Your fourth and fifth digit will include your
ring finger and your pinkie, anatomical position
fourth and fifth, one, two, three, four and
So, these two, the pinkie and the ring finger.
The metacarpal phalangeal joints in the fourth
and fifth, interesting enough and very specifically
for pseudohypoparathyroidism, will be shortened.
In addition, that knuckle-knuckle, dimple-dimple
literally means you find a knuckle in the
first, excuse me, the first, second and third
metacarpal phalangeal joints are perfectly
okay and then you find dimpling of your fourth
and fifth metacarpals.
Interesting, isn’t it?
You make this diagnosis on your wards you
will be then carried down the ward as if you
are ha, ha, royalty.
The symptoms are not improved by administration
of PTH, for obvious reasons.
The receptors and the mutation is something
that you very much want to commit to memory
is called GNAS mutation.