Here, we’ll take a look at hydrocephalus.
What can you expect?
Increased intracranial pressure.
What are the different ways in which
we can develop hydrocephalus?
Well, interesting enough,
be careful with this one.
Each one of these bullet points
that I’m going to give you here
So what does hydrocephalus
mean to you?
It means that within the,
let’s say, subarachnoid space
or so it appears that the subarachnoid
space is accumulating fluid.
Hydro-, hydro-, hydro-.
But what if you’re not?
What do you mean?
Well, what if the ventricles
look like they’re dilated?
I want you to focus on
the lateral ventricles.
Are you there?
I want you to go ahead and
think about transverse section
of your lateral ventricles and looks
as though that it’s enlarged.
So maybe it’s fluid
accumulating in there,
resulting in hydrocephalus.
But, there’s absolutely no indication
of increased intracranial pressure.
Hydrocephalus ex-vacuo is seen in asymptomatic elderly people or patients with Alzheimer's disease and associated brain atrophy.
It has compensatory enlargement of the CSF spaces witch is a term used to describe the increase in the volume of CSF characterized on imaging.
This is due the enlargement of cerebral ventricles.
For this reason, some patients with normal pressure hydrocephalus are misdiagnosed with Alzheimer's disease.
But your patient is 70 years of
age, forgets everyone’s name.
Even walks out the door
naked and never comes back.
Obviously referring to
And what do you know about Alzheimer’s
and the size of the brain?
So now, the cerebral
cortex is undergoing
atrophy, atrophy, atrophy,
The more that the brain parenchyma –
Are you picturing
this for me, please?
Close your eyes and picture this.
As the brain and its
parenchyma’s undergoing atrophy,
let it be Alzheimer’s or maybe
there is frontotemporal dementia
formally known as Pick's disease,
then, the ventricles look as
though that they’re enlarged.
It looks as though that there is
going to be cerebrospinal fluid.
So just keep that in mind
as being an important
differential in dealing
and that is specifically called
ex-vacuo that I’m referring to.
But in general, when you’re
dealing with hydrocephalus,
dilation of the ventricles perhaps
due to cerebrospinal fluid.
But then, the next question is –
How did cerebrospinal fluid accumulate
within the ventricles is your question.
Because this will then give
you the clinical description
of what type of hydrocephalus.
Is it communicating?
Is it noncommunicating?
If you’re being
confused with that,
trust me, by the time we’re done
with this section right here,
you’ll be golden.
First, let’s begin with
So what does communicating
mean to you?
I want you to picture for me
once again, transverse section,
or maybe sagittal section, in which
you’re noticing the lateral ventricles.
You’re moving into the third
and then fourth ventricle,
and then what do
you come out of?
Who comes out of?
The cerebrospinal fluid.
It comes out of the Luschka and it
comes out of the Magendie, don’t they?
And as long as that is open between the
lateral third and fourth ventricles,
out through the apertures,
bathing the spinal cord,
then it’s all communicating.
Now, how in the world can you have an
increase in intracranial pressure?
“How can you accumulate
if there’s perfect communication
with the ventricles, Dr. Raj?”
where does your cerebrospinal
fluid get drained?
Where does it get drained?
Good. Arachnoid villi.
The arachnoid granulation.
So after you bathe your spinal cord,
you make your way up into the sinuses.
And then you’re going to drain
into the arachnoid granulation.
So what if there is meningitis
and post meningitis?
Or for whatever reason, let’s
say, there was fibrosis
and there’s scarring taking place over
the arachnoid villi and granulation.
If that occurs, you
can no longer drain.
What are you going to result in?
Increased cerebrospinal fluid
in the subarachnoid space.
But the communication
existed, didn’t it?
My problem was up in the
So you call this a communicating
type of hydrocephalus.
Hydrocephalus is a common complication of TB meningitis.
The most common type of hydrocephalus in that scenario
would be communicating hydrocephalus due to extensive
scarring of the arachnoid granulation.
Rarely, an obstructive form of hydrocephalus is seen in TB meningitis
due to the obstruction of the foramena of magendie and Luschka.
And if that’s the case, may
result in hydrocephalus,
most likely the
what may happen here?
A noncommunicating has a
list of differentials.
Lists of differentials that are long.
what’s the most common
brain tumor in a child?
Medullablastoma may be
affecting your cerebellum,
And therefore, compressing
upon the fourth ventricle.
What’s the most common type
of astrocytoma in a child?
What if you find a cystic type
of image on the cerebellum?
The most common type of astrocytoma
in a child will be pilocytic.
This may then cause compression upon
the fourth ventricle, are you with me?
What’s the name of the condition
in which your posterior fossa
might become too small?
Think about the posterior fossa.
What if it’s too small,
what’s it going to do?
I’m pushing my occiput
forward, forward, forward.
What am I going to do?
I’m going to then compress
my fourth ventricle.
This is called Arnold-Chiari.
You see as to how the list is a little bit
longer here with noncommunicating, right?
Or for that matter, any
that is then causing blockage
of cerebrospinal fluid
from passing through your lateral
third or fourth ventricle
is called noncommunicating
obstructive type of hydrocephalus.
Compression of third or lateral ventricles
by mass or mass effect from edema.
Any type of mass, which is then causing
lack of communication is obstructive.
Now, obviously, here, if you don’t
treat this, at some point in time,
we will discuss our different
types of herniations.
Maybe it’s subfalcine.
Maybe it’s your transtentorial,
But obviously, the brain parenchyma
is then going to herniate
in whatever region
if left untreated.