Hello and welcome to
In order for us to fully
comprehend cerebral aneurysms,
it’s important that you understand the
anatomy of your circle of Willis.
And when, here, we refer to aneurysms,
we’ll be strictly looking
at the circle of Willis
and so therefore the caliber of your
blood vessels will be a little larger.
You’ll see what I’m referring to.
So here’s the circle of Willis and I'm not
going to through the details obviously.
However, a few things that I
wish to bring to your attention.
I want you to pay special attention
to anterior communicating artery
and the reason for that is
because if there are aneurysms –
What does an aneurysm
mean to you?
It’s a ballooning or expansion
of your blood vessel, correct?
And if there’s an aneurysm,
at any point in time,
you’re always worried about
an increase in tension and pressure,
resulting in a possible tear.
And that’s where we’re headed
eventually, aren’t we?
The reason that I bring anterior communicating
artery to your attention is because,
let’s say, 40 to 60% of your
aneurysms will be taking place
in the anterior portion
of the circle of Willis.
And you should very well know that.
Apart from that, we have the
large middle cerebral artery.
We have spent time with that earlier
when we talked about strokes.
And then I want you to focus
upon the basilar artery.
And from the basilar
artery down below,
we have the posterior
inferior cerebellar artery.
All of these of course incredibly important
when we’re dealing with strokes.
Each one of these will give you
different symptoms in your patient.
With the berry aneurysm
is what we look at here.
It’s also called a
And by saccular, we mean that the entire
wall, meaning to say the caliber,
the circular nature
of the blood vessel,
every part of it has undergone weakening
and so therefore, there’s a saccular
aneurysm, a.k.a. berry aneurysm.
Rupture is the most
And so imagine anything that’s causing
increased tension or pressure
of your blood vessel or perhaps even
weakening of the wall of the blood vessel
such as Marfan or Ehlers-Danlos,
could result in berry aneurysm and
then eventually could rupture.
And when it does, of
course, it is then
causing hemorrhage into
the subarachnoid space.
On a scale of one to ten, with ten
being the worse possible pain
that the patient experienced,
the patient is definitely going
to scale it as being ten.
We’ll talk about this as a
separate topic in a little bit.
Whenever there’s hemorrhage
that’s taking place, keep in mind
of its proximity to the
parenchyma of the brain,
so therefore it could result in
also intraparenchymal bleeding.
And that of course makes perfect
anatomical sequential sense.
And as far as the rupture is
concerned, most commonly,
it would be found in the fifth decade
You have probably already
looked at and memorized
polycystic kidney disease
with that increase in hypertension,
and eventually resulting in
berry aneurysm and rupture.
But apart from that, please make
sure that you know anything
that’s causing increase
pressure even hypertension
over a long period of time or weakening of
the integrity of the blood vessel wall,
will result in such an aneurysm and
rupture as being a complication.
Larger aneurysms can
present as mass lesion.
And symptoms will then result in
compression type of
neurologic structure issues.
It may result is such compression and
therefore affecting the third cranial nerve
and this of course referring
to your oculomotor.
And when we say involving the pupil,
please don’t forget from neuroanatomy,
that when you’re dealing with cranial
nerves, that you should also know
as a mixed function,
that there could be autonomic
nervous system, specifically,
nervous system, correct?
With the oculomotor.
And the if oculomotor has been lost,
you have now also lost the
ability to properly constrict.
And so therefore, you
could have a blown pupil.
In other words, a mydriatic type of pupil.
If the pupil is spared, then like
infarction of the nerve, seen in diabetes.
And that’s important,
If the pupil has been spared,
then likely infarction of the
nerve secondary to diabetes.
Are we clear about this?
A very important clinical point.
If the pupillary constriction
has been lost centrally,
then maybe there is a
compression type of issue.
In this case, the large berry
aneurysm is the cause.
But if the pupillary
constriction is intact,
that means that it’s more
of a peripheral issue.
Infarction should come to mind.
For example, the infarction,
therefore resulting in
compromise of nerve activity,
as in diabetes.
If you’re not familiar
with that in neuroanatomy,
please make sure that you’re
very keen upon that point
so that you can understand
your clinical presentation.
It is a big deal.
Continuing our discussion
of berry aneurysm.
The natural history of it.
If it was to rupture, it may result in
SAH, stands for subarachnoid hemorrhage.
Now, once subarachnoid hemorrhage
does occur, 2% of population
maybe seen as being
Now, one thing that you’re
definitely worried about
is that this bleeding
Unfortunately, there could
be a recurrent hemorrhage
and remains a serious consequence and
to a point where the case fatality rate
is now nearing 70% for
persons who are rebleeding.
That is a big deal.
Make sure that you digest that
particular point, please.
Our topic, an aneurysm that has ruptured
resulting in subarachnoid hemorrhage.
Now, in the prospective
Cooperative Aneurysm Study, CAS,
rebleeding was maximum,
4% on the first day after SAH
and then constant at a rate of 1 to 2%
per day over the subsequent 1 month.
And what does that
rebleed mean to you?
It increased the rate
of mortality up to 70%.
You understand the significance?
Long-term risk, 3% per
year after three months.
So the risk does decrease if you’re
able to properly manage them.
Please make sure that
you’re quite aggressive
in terms of how quickly this occurs or
when you can expect the rebleeding,
which is usually
about first day,
and then constant over the
next following four weeks.