The second thing we ask when
evaluating a stroke patient is,
is this stroke, cortical,
subcortical or brainstem in localization?
When we're looking at the patient
and examining the patient,
the findings that we see help us
to localize to a certain territory
and can hone in on a blood
vessel that we're concerned about
or the likelihood of
recovery with intervention.
So let's walk through
some of those regions.
Cortical avascular territories
that supply the cortex
include the ACA, MCA, PCA,
and both of those watershed territories,
ACA-MCA (Watershed) and
Vascular territories for a subcortical
localization are basal ganglia,
and the internal capsule specifically.
And then in brainstem we think about
strokes affecting the midbrain:
pons, medalla and the
So let's walk through each of those
localizations, each of those territories
and understand better how
patients will present.
And let's start with a
What does it look like to
have a cortical stroke?
What do we see on patients
and what's going to tip us off
to those arteries ACA, MCA,
PCA and the watershed territories?
Well first, cortical strokes
imply a large territory,
both the subcortex and frequently
the cortex are involved.
And that suggests and tips
us off that we should be
initially concerned about
an embolic phenomenon.
Large territory strokes come
from a very proximal clot,
the proximal blood
vessels are large
and so we're looking
for a large clot,
typically of an embolic source,
or sometimes intracranial atherosclerosis
that's developed over
a long period of time.
These patients are at risk for
recurrence if it is embolic,
so we really want to diagnose
the embolic phenomenon
and intervene to prevent
that from worsening.
And patients with large territory
strokes affecting the cortex
are at risk for swelling,
brain swelling, mass effect,
pressure, and herniation.
The signs of a cortical
stroke are cortical signs.
Language or aphasia
is a cortical finding.
And so aphasia suggests
the MCA territory,
either the frontal lobe
for expressive aphasia,
the temporal lobe for
the arcuate fasciculus,
if repetition is involved.
Patients may have
the frontal eye fields are located
in the cortex of the frontal lobes
and problems strokes affecting
the frontal eye fields
can cause patients to prefer to
look to one side or the other.
Neglect is a parietal
and patients who present
with prominent neglect
will worry about pride or
involvement of their stroke.
Cortical sensory findings,
stereognosis or graphesthesia
are also cortical findings suggestive
of a parietal localization.
Personality changes from
cortical frontal dysfunction,
and homonymous hemianopia is
an occipital cortical function
where we would worry about
about post your circulation,
a cortical localization.
When we think about
strokes involving those signs and
suggestive of a cortical process,
we are worried about large and
medium size vessel occlusions.
And this can point
us to the etiology,
as well as have
implications for treatment.
So the three things we worry
about is causing cortical strokes
are emboli which cause proximal
large vessel occlusion or LVO,
large vessel occlusion.
large and medium size vessel occlusion
that occur in patients who
have significant risk factors
or long term develop a
development of atherosclerosis
and thromboembolic disease.
These would be areas of
clots on the carotid arteries
that embolize distally to the
large and medium sized vessels,
again causing occlusion.
So when we evaluate patients if we're
worried about an embolic phenomenon,
we want to evaluate the heart.
Cardioembolisms or embolisms
that arise from the heart,
and we look at the heart with
a transthoracic echocardiogram.
We do an EKG or telemetry to evaluate
for paroxysmal atrial fibrillation,
which could give rise
and we consider anticoagulation.
If we're worried about thrombotic
disease or also thromboembolic disease,
we need to evaluate for a source
or a site of the thromboembolism.
We look at the carotid arteries
with carotid ultrasound
or angiography of
the carotid arteries.
And we want to manage patients risk
factors with risk factor modification,
reducing high cholesterol, managing
diabetes and reducing high blood pressure.
What about subcortical
What are subcortical strokes
and what's tips us off
that we're dealing with
a subcortical phenomenon?
These strokes typically present with
hemibody motor or sensory symptoms
without cortical involvement.
So the cortical signs we just discussed,
we don't see with these strokes.
we see hemiparesis or hemiplegia,
and those would point us to
a subcortical localization.
In addition, there are some rare
syndromes that are subcortical syndromes.
That's a patient who can't
move one side of the body,
has a weak arm and leg
with superimposed ataxia,
and that implies a subcortical, typically
thalamocapsular, internal capsule,
or a thalamic and
internal capsule stroke.
We can see movement disorders from
strokes in the substantia nigra,
and sometimes globus pallidus,
and other basal ganglia structures.
Strokes in the thalamus
can cause a severe
and debilitating thalamic pain syndrome,
which is rare but very important.
And we can see thalamic aphasia is
typically aphasia is a cortical sign.
But in selective, deep thalamic strokes,
particularly left sided thalamic strokes,
we can see aphasia
from the thalamus.
The thalamus is the relay
center to all areas of cortex
and that start to contribute
to the reason for aphasia
and a thalamic pathology
and specifically in stroke.
The subcortical strokes importantly
are called lacunar syndromes.
And that's because these
strokes typically develop
from a lacunar process,
a small blood vessel,
a small vascular blood
vessel that develops clots,
and typically we think
about this in patients
who have long
So when we're evaluating
the subcortical strokes,
we think about small
The most common cause of a small
vessel stroke is a lacunar stroke.
And we also think about thrombotic
disease or atherosclerotic disease.
Lacunar strokes are heavily linked
to long standing hypertension,
that long history of high blood pressure
results in thickening of the tunica media
reduction in the lumen size
within those small vessels.
And eventually, we can see closure
and blockage of the small vessels.
Management of hypertension is
critical in lacunar strokes.
For thrombotic strokes or
we think about managing
stroke risk factors.
So again, the localization of the
stroke can drive us to the etiology,
tell us what the favorite etiology is
and help us with managing the patient.
What about the brainstem?
The brainstem is a
really large place,
there's a lot going on
with a lot of function.
How do we localize a
stroke to the brainstem
and then use that to
evaluate the patient?
Well, there are a few
hallmarks of brainstem strokes
and you can see those here.
One is crossed findings.
And that's one symptom or
sign on one side of the body.
And that same symptom or sign or
sometimes a different symptom or sign
on the other side of the face.
So weakness on one
side of the face
and weakness on the
opposite side of the body.
Sensory loss on one
side of the face
and sensory loss on the
opposite side of the body.
Those crossed findings point
squarely to a brainstem stroke.
Patients may also present
with impaired consciousness,
this is one of the only times that
stroke will cause impaired consciousness.
That's because what allows
us to be consciousness.
Conscious is two things.
The reticular activating system
which needs to work in the brainstem
and needs to light up the
Strokes are frequently not big
enough in the bilateral hemispheres
are usually don't affect
the bilateral hemispheres
to cause launches loss of consciousness
from a hemispheric stroke.
But the reticular activating system
is a small area in the brainstem.
And deep central pontine
can affect the reticular
and present with
And in addition,
we can think about brainstem strokes
and cross sectionally.
we can divide them into strokes
that affect the midbrain,
pons and medalla.
And knowing both the cranial
nerves and the white matter tracks
that course through there
can help us to localize.
we can divide brainstem strokes
into ventral findings
and dorsal findings.
And using that combination,
we can localize precisely
to where the patient's
stroke is originating from.
So let's look at that a
little bit more in depth.
First of all, brainstem strokes are
posterior circulation in etiology,
so we want to interrogate
the posterior circulation.
Vessel imaging is critical.
And typically we don't
stop at ultrasonography
but extend into CT
angiography or MR angiography
to definitively assess
the vertebral arteries
and the basal or artery and
all of its blood supply.
We need to evaluate patients for any
potential basal or artery thrombosis.
Thrombosis in the basilar artery
is a medical emergency and must
be evaluated and managed acutely.
Let's look at some of the
brainstem presentations and signs.
Quadriparesis or motor
loss in all four limbs.
If it includes the face,
implies a vascular territory
that is above the pons and involves
the pons or above the facial fibers,
the motor function of the
face comes out in the pons
or exits the brainstem
and the pons.
And so if the face is involved,
we worry about pons or above.
If there's quadriparesis weakness
in all four limbs or quadriplegia,
inability to move all four limbs
that doesn't involve the face.
We think about below the pons, the medulla
or the upper part of the cervical cord.
We can also see hemiparesis
or hemibody symptoms.
Hemibody symptoms imply loss on one
side of the nervous system or the other.
If the symptoms in the face are the
same side as the symptoms in the body,
again, we think about that
problem, that pathology,
that stroke involving either
the pons or above the pons.
If there are crossed findings,
findings on one side of the face
and the opposite side of the body
that would be a lesion
at the level of the pons.
And if the face is spared, we worry
about lesions that are below the pons.
So the involvement of the face is
critical for localizing that stroke
to above at or below the pons.
And here you can see an example
of those crossed findings.
Here we see symptoms on the left side of
the face and the right side of the body,
which implies stroke or pathology
at the level of the pons
or in somewhere
in the brainstem.
Other brainstem findings
that we can see.
Again, decreased level of consciousness
sometimes nausea and vomiting
with specific posterior
circulation or medullary pathology
hiccups, abnormal respirations.
Oropharyngeal weakness from
lower cranial nerve dysfunction.
Vertigo and tinnitus, eye movement
abnormalities either diplopia,
gaze deviation or frank gaze palsy,
the inability to move the eyes
in one direction or the other.
The brainstem controls
all the cranial nerves
and so we can see cranial