So let's understand the clinical relevance
of the cerebellar hemispheres,
subcortical white matter and gray matter
by focusing on a case.
This is a 67-year-old African American woman
who presents with a two-year history of progressive gait dysfunction,
which became progressively worse after a recent hospitalization
when she was noted to have severe truncal ataxia.
The ataxia is improved at rest and worsens considerably
when she's sitting on the bed.
She's swaying from side to side.
Or when she's standing or walking, so really with any movement.
Her exam shows a severe wide base gait,
which we see with cerebellar problems,
horizontal nystagmus and saccadic overshoot,
where the eyes are not coordinated.
when you look in one direction or the other.
Finger-to-nose-to-finger test
is slightly abnormal with mild overshoot,
and again we see or seeing problems with coordination.
An MRI is performed and reveals cerebellar atrophy,
preferentially affecting the superior vermis
more than other areas of the cerebellum.
So which of the following is the most likely diagnosis?
Well, there are a number of key features of this case.
The first is the timeline of onset.
There's a progressive two-year history
of this cerebellar disorder.
That means it's chronic and onset,
and that already us thinking about some of those acquired causes
of cerebellar dysfunction.
The second is the propagating factors.
This patient's dizziness or balance problem
is provoked by moving and improved with rest.
That's very common with cerebellar pathology.
It can be seen with vertigo and vestibular pathology.
But that movement component is something that the cerebellum does.
So when we see problems that are provoked by movement,
we want to think about the cerebellum.
In addition, this patient's exam
shows problems with cerebellar dysfunction,
wide base gait, nystagmus, saccadic overshoot,
and difficulty with finger nose finger,
are all cerebellar signs.
That means this dizziness problem
is a problem with the cerebellum and disequilibrium.
Let's look more closely at this patient's MRI scan.
We see atrophy of the cerebellum,
and here we're looking at a midline cut.
This is a sagittal MRI,
looking right at the middle of the cerebellum,
right at the area of the vermis.
We see atrophy across the cerebellum,
but preferentially affecting the upper part of the cerebellum,
that superior lobe, that top lobe along the vermis.
And there are certain conditions
that will affect only the hemispheres,
only the vermis,
and one that we think about that has a predilection
for the superior cerebellar vermis.
So what's the most likely diagnosis for this patient?
Is this a post-infectious cerebellitis,
a Chiari malformation, alcohol-related cerebellar ataxia,
or a cerebellar stroke?
Well, this doesn't sound like a post-infectious cerebellitis.
Typically, we would recognize the initial infection,
which we don't see in this case.
Post-infectious cerebellitis is an inflammatory condition.
It's often subacute and onset, and this is chronic and onset.
It's been going on over multiple years,
or two years for this patient.
In addition, and most importantly,
post-infectious cerebellitis typically affects the hemispheres.
And this is a problem that is very specific
to the cerebellar vermis.
So post-infectious cerebellitis
is not the most likely diagnosis in this patient.
Cerebellar stroke is also unlikely for this patient.
Strokes present acutely.
And again, this patient's symptoms was chronic and onset
over two years.
In addition, we often see strokes
affecting the lateral circumferential vessels
that feed the cerebellar hemispheres,
and would present with prominent appendicular dysmetria and ataxia
as opposed to vermis dysfunction.
Chiari malformation often presents with headache
and really uncommonly presents with an ataxic syndrome.
A Chiari is a description of malformation
for the cerebellar tonsils
descending down below the foramen magnum.
We don't see that on imaging on that midline cut,
and it doesn't have this type of presentation.
And so this patient is suffering from
alcohol-related cerebellar ataxia.
The patient has an ataxic syndrome
with a predilection or that superior vermis,
which is something that's very typical
for alcohol-related cerebellar syndromes.
So let's talk a little bit more about
Cerebellar Vermis Atrophy in Alcoholism.
This is the clinical relevance of understanding,
how the cerebellum is organized?
In terms of definition,
this is a primary long-term effect of chronic alcoholism,
which results in degeneration or atrophy of the cerebellum.
The entire cerebellum is involved and alcohol has a predilection
for affecting the cerebellar purkinje fibers,
but the superior vermis is most specifically affected,
and often one of the earliest areas that we see.
Patients typically present with a slowly progressive gait dysfunction
and truncal ataxia.
The vermis is involved in truncal coordination.
And that's more so affected than the appendicular functions,
as in this case.
On imaging, MRI shows atrophy of the diffusely across the cerebellum,
but preferentially affecting the superior cerebellar vermis
more so than the hemispheres.
And pathologically, what we see
is loss of cerebellar and purkinje cells
primarily in the superior vermis,
as well as the vestibular nuclei.
And so we can see, eye movement dysfunction
as was present in this case,
and can be seen in up to 43% of patients.
So it's common, something we look for.