What about a non-communicating hydrocephalus?
This can behave like a mass effect.
Mass such as a tumor
or an extrinsic obstruction of
the normal CSF drainage pathway.
Recall a few slides back,
the choroid plexus,
all the way to the subarachnoid space,
is a defined pathway.
Any obstruction along that pathway
can cause a non-communicating hydrocephalus.
Remember, the brain has had
less time to compensate
and more likely to develop intracranial hypertension.
Besides our physical and history,
imaging diagnosis can be helpful.
Generally speaking, we get a CAT scan.
The arrow is pointing to you
a very decreased amount
of lateral ventricle space.
In this MRI image,
you notice quite dilated ventricles.
This probably represents a CSF accumulation
due to the lack of absorption
rather than an obstruction.
Now, you’ve diagnosed hydrocephalus.
When do we need to treat it?
Well, indications for treatment,
which includes a ventricular peritoneal shunt,
is when the patient becomes symptomatic.
In this shunt procedure,
a catheter is placed between the ventricles,
tunneled under the skin
and introduced into the abdomen.
Although a fairly routine procedure,
it does contain some complications.
Mostly, as you can imagine,
if the catheter is in the abdomen,
intestines can loop around it.
This catheter can be clogged
and becomes dysfunctional.
It may need to be replaced.
Additionally, also remember,
sometimes the ventricular peritoneal
shunt is actually a ventricular plural shunt.
That's when the ventricular drainage
catheter is placed into thoracic –
into the thoracic space
as opposed into the abdomen.
Some reasons that neurosurgeons may
choose to place it into the thoracic space
as opposed to the abdominal space is
because of prior surgeries in the abdomen.
As we previously described,
this catheter sits in the ventricle,
is tunneled, as you can see in this schematic,
either into the thoracic space
or into the abdomen.
Now, it’s time to remind you of
some clinical pearls and high-yield
information on hydrocephalus.
Remember the classic findings of
normal pressure hydrocephalus?
Although rare, it's a popular test question.
It requires a high index of suspicion,
so you as a clinician should think
about normal pressure hydrocephalus.
If the clinical scenario
presents with classic findings,
you have your answer.
And remember, Arnold-Chiari syndrome.
This syndrome is a skull malformation
that can cause cerebellar
tonsils to displace inferiorly.
This actually causes an obstruction.
So, this would not be an example
of normal pressure hydrocephalus.
This is so-called non-communicating hydrocephalus.
This is high-yield information.
I’d encourage you to commit it to memory.
Thank you very much for joining me
on this discussion of hydrocephalus.