In this lecture, we're going to talk about the approach to ischemic stroke.
We'll evaluate a patient case and understand how we diagnose ischemic strokes.
Let's start with the case.
This is a 45-year-old man with a history of hypertension, hyperlipidemia, and diabetes,
three of the most common stroke risk factors.
He presents with a right-sided weakness and speech dysfunction.
The patient went to bed last night in his normal state of health.
When the patient awoke this morning his wife says that he did not have symptoms
and was able to speak normally at that time.
Around 10:30 a.m., he went into the shed to work in his shop.
And then at around 11:30 a.m., she found him in the shed,
on the ground without the ability to move his right side and mumbling.
EMS was called and he was brought to the Emergency Department
where he remains weak and mumbling.
On exam, he has right hemiplegia, so he can't move his right side.
This is involving the arm, the leg and the face with facial droop.
He is unable to speak. He mumbles incoherently.
He's able to follow a few simple commands, to open and close eyes,
but not other complex commands. So what's the diagnosis?
Well, when I look at this case, the first thing that I think about is the symptom onset.
And when we talk about stroke, we don't ask when did the stroke start.
Our critical question is, when was the time the patient was last normal?
For this patient, one may think that the stroke started at around 11:30 a.m.,
but the last known normal time was 10:30
and we really don't know what happened between 10:30 and 11:30 a.m.
When we're evaluating patients for acute intervention,
the ability to intervene acutely is dependent upon the time in which the patient presents.
We only have a few hours, three to four and a half hours, to intervene acutely,
so that last known normal time is critical
and for this patient we have a last known normal of 10:30 a.m.
The second thing we look at is the evolution of the symptoms over time.
Strokes cause an acute fixed deficit.
It comes on suddenly and then it stays the same.
Stroke symptoms don't evolve, they don't change over time during that acute presentation.
If we see that evolution or progression of symptoms,
we think about other things like seizure or migraine
or other potential causes of an acute onset of a neurologic deficit.
This patient presents with acute onset of a fixed hemiplegia and aphasia
and that is consistent with a stroke pathology.
The last thing we look at is signs and symptoms
that help us to localize, where is the process coming from?
We know that right hemiplegia comes from a problem in the left-side of the brain.
We also know that upwards of 90-95% of people
will have language function come from the left-side of the brain.
This patient has right hemiplegia involving the face, arm, and leg and aphasia
and both of those localized to a large territory in the left hemisphere
and specifically in terms of vascular territory,
in the left middle cerebral artery or MCA territory.
That information is going to be critical as we looked to evaluate imaging
and understand where we want to intervene for this patient
if he's presenting with an cute stroke.
And then the last important point which is a wildcard point, is the last known normal time.
And that's important for a symptom onset, it's also the important wildcard.
This is one of the most important clinical features when we're evaluating this patients.
Last known normal must be known
and that's our job as clinicians to figure this out.
So what is the diagnosis?
Is this an ischemic stroke, a TIA or transient ischemic attack,
a focal onset seizure, or a migraine?
Well, TIA is something that we would consider in patients
who are at risk for stroke and this patient has stroke risk factors,
hypertension, hyperlipidemia, and diabetes.
But a transient ischemic attack is transient,
by definition the symptoms should resolve within 24-hours,
but operationally and clinically,
we typically see symptoms resolve within several minutes, 30 minutes to an hour.
This patient has had fixed symptoms since the timeline of onset
and at this point we would be concerned for a fixed etiology I supposed to a transient event.
We said migraines can mimic a stroke particularly acephalgic migraines
that involved neurologic symptoms can present without headache
and with neurologic deficits that is rare
and often migraines, as they develop evolve over time.
They're not that acute fixed deficit but an evolving or progressive deficit
that we can see in patients who have a complicated migraine
or neurologic symptoms with their migraine.
This patient has no history of headache, no aura,
and no other history suggests a migraine phenomenon
and this would not be our initial favored diagnosis.
Importantly, migraine causing neurologic symptoms is a diagnosis of exclusion.
Focal onset seizures can cause a Todd's paralysis.
Todd's paralysis is weakness on one side of the body
or the other as a result of a seizure that started in one area of the brain.
A focal onset seizure in the post-ictal phase can cause focal weakness or Todd's paralysis.
In this case, though there we're no clinical signs to suggest seizure activity,
if we see a Todd's paralysis, we like to see evidence of focal motor activity during the seizure
and the clinical presentation doesn't support this diagnosis.
So this is a great example of a patient presenting with an acute ischemic stroke.
The symptoms favor a left middle cerebral artery territory stroke,
and he's last known normal sounds like within one hour of presentation.
This is someone we're going to want to fast track to an early intervention.