You might be missing up to 20% of strokes. This week we discuss EMS stroke assessment tips that will up your stroke recognition game with an emphasis on posterior circulation events.OneKit First Aid Kits
What if I told you that you might be missing 20% of strokes in the field? Would you believe me?
You’re listening to 911cast, the no-nonsense EMS podcast. I’m Scott Topiol, and this week it’s all about stroke.
Stroke is a time-sensitive emergency. During an acute stroke about 2 million neurons die each minute, that’s 120 million dead brain cells in just one hour, the equivalent of 3 ½ years of accelerated brain aging.
There are two basic types of stroke: hemorrhagic and ischemic. Hemorrhagic strokes occur when a blood vessel ruptures and bleeds into the brain. These are the ‘wet’ strokes.. An ischemic stroke occurs when a clot forms in one of the brain’s blood vessels, blocking blood flow. These are the “dry” strokes since the clot stops blood from flowing, leaving the pipeline beyond it dry.
Ischemic strokes are the most common, making up almost 90% of cases. Hemorrhagic strokes, although less frequent, are more deadly, killing about half of their victims compared to around 25% for ischemic strokes. Both types of stroke can result in permanent, life-altering disability. Oh, and if you think you can tell the difference between an ischemic stroke and a hemorrhagic stroke just by the symptoms, think again. I’ve seen plenty of neurologists guess wrong; the only way to know the difference is with a CAT scan.
Stroke symptoms occur suddenly and typically include things like unilateral or one-sided facial paralysis or droop, arm weakness or drift, or abnormal speech such as slurring or difficulty getting the right words out.
You’re probably very familiar with these symptoms as they’re been drilled into most of us during EMT or Paramedic school. To help you identify stroke, your system probably has you use an assessment tool like the Cincinnati Stroke Scale or the Los Angeles Motor Scale. For many of us that’s our entire stroke assessment.
Now consider this. You’re called to the home of a 68-year-old woman. She tells you that she started feeling dizzy while eating lunch about half an hour before you arrived. Her face is symmetrical, her grips are strong and equal, and her speech is clear. Her vital signs are as follows: Blood Pressure: 182/96, Heart Rate: 66, Respirations: 14, O2 saturation 98% on room air, blood sugar: 102. Her 12-lead EKG reveals normal sinus rhythm without ectopy. She tells you that she probably hasn’t been drinking enough water and that she’s planning attending her granddaughter’s wedding tomorrow and doesn’t want to go to the hospital unless it’s really necessary. What do you say to her?
The problem with relying solely on screening tools or the presence of classic symptoms is that by doing so you end up missing lots of strokes. By some accounts as much as 20%. A stroke can be caused by a problem in any blood vessel within the brain. Yet these classic symptoms and screening tools only help you identify so-called anterior circulation strokes. When a stroke affects other parts of the brain the symptoms can be very different, and your usual assessment might lead you astray.
Posterior circulation strokes account for roughly 20% of ischemic strokes. This is a pretty sizeable percentage, yet there isn’t a reliable screening tool that you can use in the field to detect them. Common symptoms of this type of stroke include vertigo, slowed or slurred speech, balance or coordination problems, nystagmus—those strange, rhythmic eye movements, or visual changes like blurred, double, or loss of vision.
Let’s talk about vertigo for a minute. Vertigo refers to the sensation of movement despite a person being still. This is different from dizziness which doesn’t involve a feeling of motion but rather lightheadedness or feeling like the bottom’s about to drop out. The reason I bring this up is because distinguishing vertigo from plain old dizziness is an incredibly important but often overlooked part of stroke assessment. Vertigo is a common finding in patients experiencing posterior stroke. In fact, vertigo might be the only symptom present.
While I generally don’t like to give absolutes when it comes to assessment, this is an exception so here it goes: ANY time a patient tells you that they’re feeling dizzy, ask them point-blank: “Does it feel like you’re lightheaded or does it feel like the room is spinning or that you’re moving?” Be sure to include the term “room spinning” because patients commonly describe that exact sensation when experiencing vertigo. If they report sudden vertigo, you’re dealing with a stroke until proven otherwise. Of course, some patients have a history of vertigo that has nothing to do with stroke. In those cases, consider the possibility of stroke if they tell you that their current vertigo feels different than what’s normal for them.
Other subtle or atypical stroke symptoms to be on the lookout for include things like balance problems, unexplained sensations of burning or freezing to part of the body, difficulty swallowing, loss of the ability to sense temperature on one side of the body, ringing in the ear, or a sudden severe headache with no known cause.
In general, think stroke whenever a patient or family member reports a sudden neurological symptom—even if it’s resolved by the time you get there. A transient ischemic attack or TIA that involves stroke-like symptoms that got better on their own should still be treated like a stroke from an EMS perspective.
After identifying a stroke, the most important thing you can do is establish a precise last known well time. This is the time when the patient was last known to be without any stroke symptoms. It’s this time that the hospital will use to decide what treatment—if any—the patient will receive. We already know that time is brain—remember, every minute that treatment is delayed means another 2 million dead brain cells. Stroke treatments are very time sensitive and in many cases there’s virtually nothing that can be done for the patient once they exceed 4 ½ hours with symptoms.
So, before you leave the scene make sure you’ve questioned everyone to get this time right. If a patient tells you that they went to bed at 10 pm feeling perfectly normal and woke up at 6 am with arm weakness then 10 pm is their last known well time. But what if you ask their spouse if they remember if the patient got up on in the middle of the night to go to the bathroom? What if they tell you that they saw the patient—without any symptoms—get up at 4 in the morning and then go back to bed. Now we’ve gone from 8 hours since the last known well to 2 hours. In other words, the patient may now be eligible for treatment whereas they wouldn’t have been before.
Notice that I used exact clock times to describe the last known well. Never document or report relative times. If a family member tells you that the patient’s symptoms started “30 minutes ago” verify what actual time that was such as 1:15 PM and from that point forward always use the exact time. You’d be surprised how many times “30 minutes ago” gets repeated after you leave the hospital and—before you know it—nobody knows when the stroke actually started. Also, if you can bring a witness with you to the hospital that’ll help the neuro team decide on treatment. If a witness can’t come, get a good telephone number for that person to be reached and let the know to answer the phone even if they don’t recognize the number. The information they provide to the doctors in the hospital is often used to decide how to treat the patient.
Let’s go back to our case of the 68-year-old woman complaining of dizziness while eating lunch. You question her more about her dizziness and she tells you that it came on suddenly and it feels as if the room is spinning. Despite not having any other obvious neurological deficits you tell her that the sensation she’s feeling could be caused by a type of stroke, note her last known well time, and convince her to go to the hospital where she’s found to be experiencing a posterior circulation stroke that’s successfully treated with the clot-busting medication, tPA.
EMS providers are taught to recognize common symptoms associated with anterior circulation strokes, but many strokes affect other parts of the brain and can present with subtle or abnormal symptoms that are easily missed. These strokes are just as important as ones that cause facial droop, extremity weakness, or slurred speech. By rapidly identifying stroke symptoms, establishing a precise last-known well time, and ensuring transport to an appropriate stroke center, you increase the likelihood that the patient can receive treatment—potentially sparing them from lifelong disability or even death.
That’s it for this week’s episode of 911cast. Please subscribe and consider reviewing us on iTunes.
I’d like to thank OneKit for sponsoring this week’s episode. Check out their professional grade first aid kits and complete first responder kits at buyonekit.com. That’s B-U-Y-O-N-E-kit.com.
Until next week, thanks for listening.