context: A stroke happens when the flow of blood to part of your brain gets cut off. This means your brain can't get oxygen, and without that, brain cells can be damaged in minutes. That's why it's important to get to the emergency room right away if you think you're having a stroke. You'll probably need a clot-busting drug within the first 3 hours. Signs of a stroke can be different for different people. The F- A- S- T test is an easy way to remember them: Face: Smile. Does one side of your face sag? Arms: Raise both and see if one droops. Speech: Say a common phrase: Does it sound strange or slurred? Time: Call 9-1-1 right away if you notice any of these symptoms. Note what time they started. At the hospital, your doctor will want to rule out other conditions that might cause your symptoms. These could include seizure, migraine, low blood sugar, or a heart problem. Your doctor may: Ask when your symptoms started and get information about your medical history Check how alert you are, and see if you can't move one side of the face or you have trouble with coordination and balance Check if you feel numb or weak in any part of your body See if you have trouble with your vision or speech Do a physical exam, take your blood pressure, and listen to your heart Your doctor then will need to do blood tests and imaging tests to figure out which type of stroke you might have had. The most common kind is called ischemic stroke. Almost 90% of people who have a stroke have this, and it happens when a clot blocks blood flow. A hemorrhagic stroke is when you have bleeding in your brain. Complete blood count. This includes a check for your level of platelets, which are cells that help clot blood. A lab will also measure electrolyte levels in your blood to see how well your kidneys are working. Clotting time. A pair of tests called PT (prothrombin time) and PTT (partial thromboplastin time) can check how quickly your blood clots. If it takes too long, it could be a sign of bleeding problems. Computerized tomography ( CT). Your doctor takes several X-rays from different angles and puts them together to show if there's any bleeding in your brain or damage to brain cells. They may put dye in your vein first to look for an aneurysm, a thin or weak spot on an artery. Magnetic resonance imaging ( MRI). This uses powerful magnets and radio waves to make a detailed picture of your brain. It's sharper than a CT scan and can show injuries earlier than a traditional CT. Carotid ultrasound. This uses sound waves to find fatty deposits that may have narrowed or blocked the arteries that carry blood to your brain. Echocardiogram. Sometimes a clot forms in another part of the body (often the heart) and travels to the brain. This imaging test of the heart can look for clots in the heart or enlarged parts of the heart. Angiograms of your head and neck. Your doctor will put dye in your blood so they can see your blood vessels with X-rays. This can help find a blockage or aneurysm. Your doctor may put a clot-busting drug called t PA in your arm. You should get it within 3 hours of the stroke. In some situations, you can get it 4.5 hours later. You'll probably have it while you're still in the ER. If you can't have t PA, which is a powerful drug and can cause bleeding, you might take aspirin or another medicine to thin your blood or keep clots from getting bigger. Another option is to remove the clot after you arrive at the hospital. Your doctor will thread a device called a stent up the artery to grab the clot, or take it out with a suction tube. They also can use a tiny, flexible tube called a catheter to send drugs up to your brain and directly to the clot. The first goal is to find and control the bleeding. If you take blood thinners, the doctor will take you off them. The next step depends on what caused your stroke. The No. 1 reason for a hemorrhagic stroke is uncontrolled high blood pressure. If this led to yours, you'll probably need to take medicine to lower it. If an aneurysm caused your stroke, your doctor may clamp the broken vessel closed or thread a tiny coil through it that helps to keep the blood vessel from bursting again. You'll take medication to sleep through either procedure, and you'll recover in the hospital. Tangled blood vessels also can cause a stroke. ( Some people are born with these.) In that case, your doctor might take them out with surgery, use radiation to shrink them, or use a special substance to block the flow of blood to them. Once they treat the cause of your stroke, your doctor will work with you to lower your chances of another one. For example, they may help you keep your blood pressure in a healthy range.