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Acute treatment of stroke with medications
- [Voiceover] After you start to recognize that someone might be having a stroke, right, maybe they have some of the symptoms we know to be common stroke symptoms, like maybe one side of their face starts to droop. Or maybe all of a sudden they have some vision loss or some numbness or weakness on one side of their body. Then you want to make sure that this person gets to the hospital as quickly as possible because remember more than any organ in the body, our brains love oxygen. Brain tissue cannot live without it even for a few minutes, so in a stroke when blood stops flowing to a part of the brain and thus deprives the brain of the oxygen it carries, the brain tissue that's missing out on oxygen starts to die off. So super important that whoever you're suspecting of having a stroke is taken to the hospital as quick as possible to save as much brain as possible. So now that we're at the hospital, what goes on there, what's gonna happen? A few things are gonna happen. I mean the plan is to diagnose the stroke, right, with some tests and some imaging, and then to treat the stroke with some medications. So let's take a look. We know that part of diagnosis includes a physical exam to look for any physical signs that the person has had a stroke. Really importantly, it also includes imaging like CT and MRI scans. It includes lab tests, blood work to look for an underlying cause of the stroke or to rule out other diagnoses like hypoglycemia, which can look like a stroke. The kind of treatment that the person gets really depends on the type of stroke that they had. Let me show you what I mean here. You could've had an ischemic stroke, for example, where a clot blocks off a bit of blood vessel in the brain and causes a stroke that way. Or you could've had a hemorrhagic stroke, for example, where a weakened blood vessel in the brain starts to leak, maybe because of a ruptured aneurysm or some trauma to the head, like from a fall or something unpleasant like that. But how does the type of stroke you have influence treatment? Because for ischemic strokes, which you can usually identify on imaging, actually let me clarify that. You won't be able to see any brain changes on CT scan right after a patient's had an ischemic stroke. That's why this CT up here looks pretty normal. But the key is that it doesn't look like a hemorrhagic stroke CT scan, which I'll show you in a few minutes. So the patient in whom you're suspecting an ischemic stroke gets certain medications that you definitely do not get in hemorrhagic stroke. Let me show you what I mean here. Let me bring up a blood vessel here to just show you how these medications work. If the patient had an ischemic stroke and came to the hospital quickly enough, they'd often be given two types of medication. One is aspirin, and aspirin doesn't actually do anything about the existing clot. It can't break it up or anything like that, but what it can do, what it can do is prevent new clots from forming. So it stops platelets in your blood from working properly because platelets in your blood are responsible for forming the initial component of a blood clot. It stops those from forming. Really importantly, you might be given a type of medication called a thrombolytic. This thrombolytic is the one that can potentially break up that clot that's causing the stroke, right? You might have heard of clot-busting medication and this would be type of that. Thrombo means clot and lytic means to break something up. This one in particular is called tissue plasiminogen activator or TPA. That sounds like a pretty confusing name but it's called tissue plasminogen activator because of what it does. It activates a compound called plasminogen that's already naturally found floating around in your blood as part of the body's natural mechanism to break up any clots that shouldn't be hanging around. So TPA sort of kick starts this natural system already in your bloodstream to try to bust up the clot that causes the stroke, right? Actually when plasminogen gets activated by TPA, it turns into this compound called plasmin and that's what's actually doing the busting up, the clot busting, that's why I wrote plasmin here. Really importantly about this drug, the benefit of TPA is the highest right after the stroke has occurred, and then it just kinda gets less and less effective from there. Again, I'm just trying to highlight the fact that the earlier the patient gets to the hospital, the better the outcome, the better the TPA will work. That's ischemic strokes. That's acute management of an ischemic stroke. With hemorrhagic strokes though it's a different story because when you have vessels that are bleeding out, the first thing you want is for it to clot off and stop bleeding, and therefore the last thing you want is to activate your plasminogen clot-busting system. You won't be given TPA because if you are given TPA, then your blood will be far less likely to clot, right, as we saw earlier. Blood will just continue to pour out of this deficiency in the blood vessel here, see? Actually let me bring up a CT scan of a hemorrhagic stroke. You remember I said I was gonna bring one up. You can see all of this blood here. This bright spot is a big collection of blood that's been sort of leaking out of blood vessels in the brain that have ruptured. You can see that this looks really different from the CT scan over here on the left of an ischemic stroke. This is why brain scanning is super important when you're diagnosing a stroke 'cause it really has big implications on how you treat the stroke afterward. For hemorrhagic strokes the focus of initial treatment has to be a little different than with ischemic strokes. For example, with hemorrhagic strokes it's really important to find out which blood vessel's bleeding, so where exactly in the brain the bleed is. That can be done by the imaging tests like CT or MRI or angiography that we talked about. Because the goal is to stop the bleed, it's important to first know where it is. Another thing, anytime you're bleeding from a vessel, right, losing blood, your heart starts to get a little worried, right? Good ol' heart always looking out for you. It starts to pump blood out a little harder and it's thinking that that's what it'll take to get blood going everywhere again. Now your blood pressure's gone up. But there's two main drawbacks to that. One is that if a little clot has started to form, right, to seal up the initial tear in the blood vessel, is that new maybe not so stable clot gets hit with blood racing along at high pressure, it might get dislodged and rebleeding might happen. The second drawback to blood pressure that gets too high is, let's say that a clot hasn't formed and it's still bleeding, it's still active. Then now blood'll just start coming out of the vessel even faster, right, and that's probably the last thing that we want. The patient might be given antihypertensives or blood pressure lowering drugs to try to keep the blood pressure from getting too high. It's also really important with hemorrhagic strokes that the healthcare team stops or reverses the effects of any medication that the patient's regularly taking that might increase bleeding, such as warfarin or the aspirin that we mentioned earlier. Also really important is that pressure building up in the brain and the skull from all this blood is controlled. For starters one simple way to do that is to just make sure that the head of the patient's bed is elevated. This works just because of good ol' gravity. When the patient's head is elevated, then more blood will flow out of the head in the jugular veins, right? That's one way of lowering pressure in the head a bit. One reason why keeping pressure in the head at a normal-ish level is really important is that when your brain starts to get pushed on or compressed, it kinda disrupts the normal electrical activity in the brain and you could end up having a seizure. So the doctors might consider giving an anticonvulsant, which is a medication to prevent seizures from happening. Another reason is just because some pretty vital areas in your brain, particularly your brain stem, they might get compressed with all of this pressure building up and that's pretty quickly fatal so we don't want that. There are some other surgical ways to keep pressure under control but we won't focus on that right now. But you can definitely start to see that management of hemorrhagic stroke is really about managing the patient until interventions like surgery can happen. Whereas with ischemic strokes, while you might still need more invasive treatment down the line, at least you can give TPA initially to try to get things resolved beforehand, try to bust up that clot before you need more invasive treatment. So that's a quick look at some of the immediate management of ischemic and hemorrhagic strokes.