00:01
Let's take a look at increased
intracranial pressure.
00:04
There are many ways in which
intracranial pressure could be increased
and we've discussed this a few times.
00:11
For example, if there's
any type of hydrocephalus
that could be an increase
in intracranial pressure.
00:16
There are a few other important topics
that we have to have to take
a look at, including herniation,
resulting in once again increase
in intracranial pressure.
00:24
So there's a long list of
differentials, but here,
let's organize our thoughts and
take a look at what happens.
00:32
We have something called a Monroe
doctrine, a "brain in a box".
00:37
So in other words, let's
say that you have the box,
which is then increasing the pressure
due to what ever reason in the brain,
increasing its pressure.
00:48
The skull of course contains the
brain, the CSF and the blood.
00:51
And so therefore, any one of those,
in which it's undergoing, let's say,
encephalitis and brain-type
of space-occupying lesion.
00:59
We talked about hydrocephalus or perhaps
even subarachnoid hemorrhage with blood.
01:04
All of this could result in
increase in intracranial pressure.
01:17
Then increase in pressure then
displaces something, doesn't it?
And that something that it
displaces is going to result in
whatever symptoms that your
patient is going to experience.
01:28
And here, let's say that our patient,
Remember we talked about
subarachnoid hemorrhage
and we talked about hydrocephalus.
01:38
And with hydrocephalus, at some point
in time, if it's left untreated,
don't you think it's once again
going to displace something?
And that something that it displaces
may then result in a herniation.
01:52
And that herniation is of different types.
01:57
And all of this, of course,
is going to contribute to
that already existing increased
intracranial pressure.
02:04
In terms of increased intracranial
pressure, think of this as being
kind of like a topic like headache,
where there's a list of differentials.
02:14
The same thing can be
applied here as well.
02:16
Now, herniation occurs when
focal or global pressure forces
portions of the brain
into the wrong spot.
02:23
So what are these different
types of herniations
that you want to be
extremely familiar with?
You want to know about
subfalcine herniation.
02:33
Don't memorize this.
02:34
What does sub- mean?
Underneath.
02:36
What is falcine referring to?
The falx cerebri.
02:41
And for whatever reason,
at some point in time, we'll talk
about hematomas as well, right?
When we talk about hematomas,
epidural or you had your subdural,
so you can have those
types of hematomas.
02:53
So remember please that you could
have a trauma resulting in hematoma
and also at the same time,
there could be displacement of the
brain parenchyma in the wrong spot.
03:06
So imagine now, you're at your
medial hemisphere of the brain
and you just got
hit by a baseball.
03:12
Boom!
And now, you resulted in, let's
say, an epidural hematoma.
03:18
In addition,
let's say that the medial
hemisphere of the brain
is now moving underneath
the falx, subfalcine,
to the wrong spot,
to the other side.
03:30
Guess what's going to happen?
Continue with your story.
03:33
What story?
What's the name of a blood vessel that is
supplying the medial hemisphere of the brain?
Aha!
Anterior cerebral artery, right?
Anterior cerebral artery.
03:45
And the medial hemisphere of the brain
is supplying what part of the body?
Is it my face or is it
the lower extremity?
Lower extremity.
03:58
So with the subfalcine herniation, it could
result in lower extremity issues.
04:04
Clear?
It's all a story.
04:06
All that you're doing from
neuroanatomy is memorizing the facts
so that you can apply the proper pathology
and the disease so that you'd tell a story.
04:15
Otherwise, you're
wasting your time.
04:18
What about uncal herniation?
What does uncal refer to?
The uncus.
04:23
Where is that?
Oh yes, anatomy.
04:26
Temporal, good.
04:27
So another name for your uncal herniation
is known as transtentorial herniation.
04:32
What is that going to do?
It's going to press
upon the brain stem.
04:36
Third cranial nerve, oculomotor.
04:39
What happens?
You lose your parasympathetic,
you have uninhibited sympathetic
activity, blown pupil.
04:45
Uncal herniation also compresses the 6th cranial nerve,
so the patient cannot move the eye outward.
04:51
Or you can have tonsillar.
04:52
What does that mean to you?
What tonsils am I referring to?
Cerebellar tonsils.
04:58
And these may
herniate into where?
The foramen magnum.
05:04
Topic: Increased intracranial pressure.
05:06
But at the same time, remember,
there are many pathologies that
could occur at the same time,
giving you different, different,
different presentations.
05:13
You just have to be very careful as to
what exactly is the clinical picture.
05:19
So then you can choose the
appropriate step of management.