When a patient presents to the Emergency Department (ED) for stroke symptoms, the evaluation occurs quickly because the potential treatment is time-sensitive.
We do our best as ED clinicians to keep patients and their families informed at every stage of the diagnostic and treatment process. Given this often progresses rapidly so as not to delay care, we want to take the time now to explain the thought and care that goes into these critical decisions.
The most common type of stroke and the one we are discussing in this article is referred to as an ischemic stroke.
This is when there is an occlusion or obstruction in a blood vessel in the brain (most often from a blood clot), depriving a portion of the brain of the blood and oxygen it needs to function properly.
What are the symptoms of a stroke, and how is a stroke diagnosed?
The symptoms of a stroke vary from patient to patient depending on the area of the brain that is affected by the blockage. Some of the most common signs include an asymmetry of the face (or ‘facial droop’), difficulty speaking (which can be either slurred speech, inability to get words out, or speech that sounds like a garbled combination of words), or loss of strength on one side of the body. Less common and more subtle signs of stroke can range from a sudden loss of vision, loss of sensation in the face, arms, or legs, an abrupt onset vertigo (room-spinning) sensation, or even confusion and disorientation.
The diagnosis of a stroke starts with a simple physical exam, and an ED physician or neurologist will evaluate the patient shortly after they come through the door.
The next step is a CT scan of the brain; however, this is often normal in the setting of an acute stroke. It is obtained to rule out other causes of the patient’s symptoms, such as bleeding or a mass in the brain. The decision to treat the patient for a stroke, therefore, is often made based on the physical exam after other causes are excluded. The most sensitive test to ultimately determine if a patient has a stroke is an MRI, an alternate imaging study that can provide a much closer look at the brain. Although more sensitive, an MRI takes significantly longer to perform than a CT scan. Moreover, this is not often part of the emergent evaluation and treatment algorithm.
Why is the treatment for stroke so time sensitive?
When a patient’s physical exam is consistent with a possible stroke, the most important initial question we need to answer is ‘When did the symptoms start?’ This is because the treatment for stroke, called thrombolytics (or tPA, for short), must be administered within a specific time frame after the onset of symptoms. This medication is injected into an IV line and works by breaking up formed clots in the bloodstream. The quicker we can administer this medication, the higher the likelihood it will treat the culprit blood clot in the brain, and prevent any long-term brain damage. The longer a portion of the brain is deprived of blood flow, the more likely the brain will suffer permanent damage and disability. This prolonged period of deprived blood flow, unfortunately, also increases the risk that a patient will develop bleeding in the brain if given thrombolytics (the most feared complication of the treatment). There has been extensive research done on this topic, which has shown that if we treat a patient within 4.5 hours of symptoms onset, they have the best chance for recovery and minimized risk for any unwanted bleeding.
So how do you decide who gets this treatment?
To be considered for thrombolytic treatment, a patient must first fulfill two important criteria: 1. their symptoms must be significant enough to warrant a potentially high-risk intervention, and 2. present within 4.5 hours of symptom onset. Given the treatment comes with a high risk of bleeding (not just in the brain, it can also result in other forms of life-threatening bleeding, such as gastrointestinal bleeding), the treatment is often not given when the symptoms are minor. It is also not safe to give to patients who, for example, are already on blood thinning medications, or have recently had any significant bleeding or head trauma. When making this decision, we go through a particular checklist that takes into account both symptom severity and exclusion criteria to determine if a patient is eligible.
What if a patient comes after the 4.5-hour window?
If a patient presents to the ED outside the thrombolytic treatment window, or if their symptoms are not significant enough to warrant the systemic treatment discussed above, there are still potential therapeutic options. After the initial CT, we sometimes obtain an additional CT scan specifically of the blood vessels in the head (called a CT-angiogram). If the blood clot causing the stroke is detected on this scan, specialized neurologists can sometimes perform a minimally invasive procedure to either remove the blood clot or use a catheter to inject the thrombolytic medication onto the clot directly. Given this does not carry the same risk of bleeding complication, it can be performed up to 24 hours after onset of symptoms.
If you or a loved one presents to a Novant hospital with stroke symptoms, as dedicated stroke centers, our ED clinicians work in close consultation with neurologists to administer the best and safest treatment in the quickest way possible. We hope patients understand the time-sensitive nature of this diagnosis and should call 911 immediately for any concerning symptoms.