context: It might start with the odd symptom. Maybe the side of your face goes numb. Or you can't lift your arm because it feels like lead. If you're having a stroke, what happens next -- and how fast -- makes all the difference in how you'll recover. That's why it helps to know how a stroke unfolds. You'll be better prepared to take the right steps for yourself or someone close to you. A stroke comes on when your brain doesn't get the blood and oxygen it needs. That could be due to a clot, known as an ischemic stroke. Or it can happen with a burst blood vessel, as with a hemorrhagic stroke. No matter which one it is, it's not long before brain cells start to die. Once a stroke begins, you lose almost 2 million brain cells every minute. That's what leads to the first symptoms you have, which can seem like some part of your brain quickly went offline. You might be grabbing milk from the fridge and suddenly your face feels funny. Or sitting at your desk and realize you can't budge your arm to answer the phone. Or you're in the middle of a sentence when you start slurring your words. In seconds, you go from totally fine to totally not. Any one of those three signs -- face drooping, arm weakness, and trouble talking -- means someone needs to call 911. Don't wait. And don't call your doctor or family members first. When you make the call, say, " I think it's a stroke." That lets the 911 dispatcher know to act quickly and get an ambulance to you right away. While you wait, don't be tempted to drive yourself or someone having a stroke to the emergency room. It might seem like forever, but the best thing you can do is sit tight. As the minutes tick by, new symptoms may set in. Still, you're much more likely to get the care you need if you wait for the ambulance. What you can do is make sure the front door is unlocked for medical workers and loosen any clothes around your neck or chest so you can breathe easily. When the ambulance shows up, they're going to act fast. They start by making sure you're breathing and you have a pulse. If not, you'll get CPR. In some cases, they'll give you oxygen. Then, they'll do a quick check to look for signs of stroke. There are different ways to do this. Often, first responders use the Cincinnati Prehospital Stroke Scale ( CPSS), where they ask you to: Smile so they can see if your face looks crooked or droops on one side Hold both arms out straight for 10 seconds to see if one arm drifts downward or doesn't move at all Say a simple phrase, like " The sky is blue," to check if you slur your words or have trouble understanding what they're saying They'll also want to know exactly what time your symptoms started. And they might check your blood sugar level. If everything points to a stroke, they send what's called a CODE STROKE to the hospital. All of this happens within minutes. Then you're speeding off in the ambulance. If there's a stroke center in your area, they'll take you there, even if it's a little farther. If not, you'll go to the nearest hospital. While you're on the way, the emergency room gets things lined up. Everyone, from lab techs to doctors who specialize in strokes, gets ready to hit the ground running. Once you're through the emergency room doors, the stroke team jumps into action. Within 10 minutes. A doctor starts a physical exam and asks you or a loved one about your symptoms and health history. Within 15 minutes. You get tests to see if you're having a stroke and how severe it might be. Your doctor checks how aware you are of what's happening and how well you see, speak, and move. You might also get some blood tests. Within 25 minutes. You get a CT scan to make an image of your brain so doctors can tell what kind of stroke you're having. Within 45 minutes. The doctor reviews the CT results. From there, it's time for treatment. For an ischemic stroke, that usually means you get a clot-busting drug. It works fast to get blood flowing back to your brain. Ideally, you get it within 60 minutes after you get to the hospital. For hemorrhagic stroke, you'll likely head to surgery to repair a broken blood vessel.