Now that we’ve looked at the basics of anterior
pituitary, let us now get into the pathology.
The first topic here is going to be pituitary
Insufficiency, that means that we’re lacking
the hormones being released from the anterior
pituitary or perhaps the posterior pituitary.
Do not forget that.
Our first cause or aetiology of our pituitary
insufficiency, in fact, is an adenoma.
Many a times med students and residents get
adenomas and think of it as only being functioning.
Do not ever do that, especially with boards.
Even though it might be a smaller percentage
of adenomas being non-functioning, if you
are not paying attention to your patient or
question, you get it wrong unnecessarily.
So, we have a space-occupying lesion within
the pituitary that is causing decreased release
or no release of a hormone at all.
We’re not quite done.
The picture that you’re seeing here, in
fact, is the pituitary.
The house of your pituitary gland in fact
is called the?
And the connection between the pituitary and
the hypothalamus, as you know and we’ve
talked about earlier, is the infundibulum
or the stock and the circulation within it
is the portal vein.
What I would like for you to do is I want
you to start thinking of this adenoma growing
and growing and growing.
Remember, if this is a non-functioning adenoma,
a space-space occupying lesion would then
knock out a respective hormone coming out
of the anterior pituitary or posterior pituitary.
But, if this adenoma continuous to grow and
let’s say that it compresses the stock,
wow, now this is what you need to know.
Listen, if that stock has been knocked out
for any reason at all, stock compression or
stock severance... if you sev-severe the stock
then the hormone that you’re paying attention
to at that point will be prolactin.
Tell me the peptide or give me the name of
the substance that-that inhibits the release
That’s dopamine that’s coming from the
brain through the hypo-hypothalamus, through
the stock, to the pituitary.
So, if you compress the stock, guess what
You cannot deliver the dopamine to the anterior
So, therefore, you lose the inhibition.
If you lose the inhibition of prolactin, you
are then going to have excess prolactin.
However, as far as all the other hormones
are concerned, it pretty much knocks them
Our topic right now is pituitary insufficiency.
I’ve walked you through in great detail
a non-functioning pituitary adenoma.
Now growth hormone usually affected first,
then FSH and LH then TSH and then ACTH last.
This is a pituitary insufficiency with an
adenoma that’s non-functioning.
So, if the growth hormone has been knocked
out as a child, obviously, we have dwarfism.
If it’s your gonadotropins, you’re respectively
man or woman; in a man, you’d have delayed
puberty whereas in a female, she’d have
delayed puberty and she would have amenorrhea.
TSH should be knocked out, you tell me what
kind of hypothyroidism?
Primary, secondary, tertiary?
See, if you did a TRH stimulation test, you
would not release TSH, would you?
And then ACTH… if that’s been lost, what
do you call that primary, secondary or tertiary
And that then brings you discussion of corticotrophin
releasing hormone stimulation test.
Are these important points that I’m making?
Absolutely because you want to know more than
one biochemical test that you’re going to
perform on your patient so that you can appropriately
confirm your diagnosis.
Isn’t that what’s most important for your
patient and for your practice and to get your
Something called pituitary apoplexy.
Do not confuse this with Sheehan.
That’s another topic, that’s pituitary
Well, pituitary apoplexy is the closest pathogenesis
that I can-I can give you with this would
be something like waterhouse friderichsen
What does that mean?
Remember waterhouse friderichsen syndrome
that you talked about in microbiology with
Neisseria species would be if there would
be sudden rush of blood and haemorrhage into
the adrenal cortex and you lose all functioning.
Well, the same kind of issue might be taking
place up in the sella.
You might have sudden haemorrhage into the
sella doing what?
Causing pituitary insufficiency.
And of all the hormones, the one that you’re
paying attention to quite importantly will
Cortisol is the most important stress hormone.
Let’s continue with aetiologies of our pituitary
insufficiency and this time we come to infarction.
So, this, of course, gives the age old presentation
that I’m sure that you’ve been exposed
to a number of times and this would be a pregnant
woman who, let’s say there is a placental
disease and maybe perhaps the placenta instead
of attaching to the decidua, attaches to the
And so, therefore, during delivery, the placenta
is now being whipped away from the lining
of the-of the uterus and in the process may
result in pretty massive haemorrhage in a
pregnant woman who is suffering from such
That massive bleeding, remember a pregnant
woman’s pituitary gland is rather enlarged,
hypertrophy, it has to be.
It’s a lot of responsibility that the pregnant
woman is taking care of.
What that hypertrophy of course means also
increased blood supply.
All of a sudden, there is massive haemorrhage
The first organ to be knocked out or to be
sacrificed unfortunately would be your pituitary
Welcome to pituitary infarction causing pituitary
Now, how would you know that the pregnant
woman is in fact suffering from Sheehan’s
Because she cannot properly breastfeed her
child all because there is no prolactin.
However, what’s the hormone that you want
to replenish to make sure the survival of
Remember, infarction, the entire pituitary
gland is probably compromised.
What else might cause pituitary insufficiency?
Maybe lymphocytic, what’s known as hypophysitis.
Usually found in postpartum women.
So, literally, there’s going to be lymphocytic
infiltration causing destruction.
Unfortunately, there is still radiation and
can’t say that it’s not without side effects
and serious issues including the fact that
radiation may cause damage to the pituitary
gland or for that matter any organ, huh?
Or you take a look at the sella and there’s
You see the house?
Well, there’s no one home.
Welcome to empty sella… pituitary insufficiency.
Or there might be infectious or granulomatous
or even cancers that may cause destruction
to the pituitary.
A list of important differentials of pituitary
Let’s walk through each one of these hormones
and what is the result of lack of that hormone
because of hypopituitarism or pituitary insufficiency?
Say that three times fast, haha!
So, say there is no growth hormone, your cartoon
here on your right is showing you a normal
male at a normal height or you find this child
who doesn’t have growth hormone resulting
IQ normal, this is not a cretin, okay?
This isn’t a patient with lead poisoning,
There’s also short stature children, but
in dwarfism, you have a dwarf... nor is your
patient here achondroplasia, right?
Achondroplasia, you look like this, short
limbs, but the head is perfectly normal, the
trunk is normal because the flat bones are
Do not get achondroplasia, which is a very
common cause of short stature and dwarfism,
and make sure you know the characteristics.
IQ here perfectly normal and it’s proportional
Next, growth hormone is a stress hormone.
So, now, let’s group together biochemically
the stress hormones that you’ve seen together.
You always put together cortisone, glucagon
that takes care of two.
You are going to put in there in the mix epinephrine
and your growth hormone.
What is the-What is this stress hormone always
going to do?
It’s always going to find a way to increase
glucose in your circulation, isn’t it?
Yes, it is.
It’s always going to promote glucose and
So, if you don’t have growth hormone, you
can expect what type of glucose levels in
Hypoglycemia in adults.
Let’s talk about gonadotropins.
If the gonadotropins have been compromised
due to hypopituitarism or pituitary insufficiency,
then there’s going to be, as we discussed,
early, delayed, retarded sexual maturation
If it’s an adult and if it’s a male, we
talked about decreased libido, impotence,
muscle loss and facial hair is not present
or is not in abundance.
If it’s a female and she doesn’t have
a gonadotropin, she doesn’t have her LH
So, therefore, she will not have an LH surge,
she will not have ovulation, she doesn’t
even have the FSH to have the proliferative
So, guaranteed your female is amenorrheic.
If there’s pituitary insufficiency and TSH
is not present, this is secondary hypothyroidism.
Your patient obviously is going to feel tired,
fatigue, slow down, a little bit of food and
increased weight and maybe constipated.
You give TRH, obviously here, you are not
going to release TSH from the anterior pituitary.
If ACTH isn’t present, this is called what?
Secondary, secondary hypocorticolism, not
If you give CRH, you are not going to find
stimulation and release of ACTH.
Here, you will obviously find decreased levels
of cortisone, but you will not find hypopigmentation
because this is not Addison’s.
Is that clear?
If you’re confused with this, it’s okay.
What this is saying here is the fact that
compared with C/W stands for compared with
Addison’s, secondary hypocorticolism will
not have hypopigmentation and that is a huge
And if you do not have cortisol, welcome to