Stroke is a general term used to describe the death of part of the brain. There are two major types of stroke: ischemic and hemorrhagic. Ischemic means lack of blood flow and hemorrhagic refers to bleeding, usually uncontrolled. Each of these two categories of stroke is then further divided into two subcategories (see next paragraph). The brain is organized by function, meaning that each part of the brain that you can see visually is responsible for a certain function in the body. This means that damaging a certain section of the brain will cause predictable symptoms. A stroke on the left outer side of the brain, for example, may cause right arm weakness. If you change that location by just a little bit, a person may experience right leg weakness. In addition, damage to that same place on the right side of the brain would cause left arm and leg weakness. This is why, when you see a victim of a stroke, they usually have one-sided symptoms. In terms of seeing someone have a stroke in front of you, there is one very important thing to remember. A stroke is treatable in the emergency department, but only within the first three hours after the stroke occurs. Because of this, it is extremely important that if you see someone with stroke symptoms, you should bring them to the hospital as soon as possible.
Stroke is a broad term describing damage to the brain’s cells (neurons). There are two categories of stroke, each of which is then divided into two more subcategories. The type of stroke you have can make a large difference in how you are treated in the hospital as well as what symptoms may result.
An ischemic stroke can be caused by a loose blood clot floating in the bloodstream until it lodges in a smaller blood vessel in the brain. This kind of stroke is called an embolic stroke because an embolus is the name for a loose object floating through the bloodstream. Ischemic strokes can also be caused by a buildup of plaque in a brain blood vessel that then has a blood clot attach to it, thereby blocking blood flow. This type of stroke is called a thrombotic stroke since the word thrombus refers to a stationary blood clot on the wall of a blood vessel.
Hemorrhagic strokes can also be divided into two subcategories. Unlike ischemic strokes, which are caused by blood flow being blocked to the brain, hemorrhagic strokes are caused by bleeding. The two types of hemorrhagic strokes are intracerebral hemorrhage and subarachnoid hemorrhage. Intracerebral hemorrhages are caused by bleeding inside the brain itself. This bleeding kills blood cells and thus causes a stroke. A subarachnoid hemorrhage, on the other hand, is caused by bleeding near the surface of the brain, which causes a pocket of bleeding that puts pressure on the brain, thus causing brain cells to die. Intracerebral hemorrhages are usually caused by high blood pressure which breaks through the walls of small blood vessels in the brain. It is from these vessels that the bleeding occurs. Subarachnoid hemorrhages can be caused by many things, but in the case of a spontaneous stroke, they are usually caused by aneurysms, which are tiny bubbles on the blood vessel that are present from birth. These small imperfections in the blood vessel have weakened walls and thus can rupture at any time, causing a hemorrhagic stroke.
The symptoms of a stroke depend on the location of brain damage. The brain is organized by function and the outside of the brain (the wrinkly part) is a virtual map of the body. An example of this is that if you damage a certain small part of the brain, your upper face might be affected, whereas if you damage a section just a little bit away, you might experience weakness to the lower part of your face. Deeper damage to the brain causes predictable symptoms as well, but they are not laid out as obviously as the “body map” on the outside of the brain.
The most common symptoms of a stroke:
If you or someone near you has any of these symptoms, you are probably having a stroke, and you should seek emergency medical care immediately. Stroke is treatable, but only within a small timeframe (3 hours from the time the symptoms started).
Women will usually experience the same symptoms as men when they experience a stroke, but they also may have some symptoms unique to their gender. In addition to having a sudden severe haedache and some or one of the sudden changes listed above, woman may also have the following:
Women have a higher overall risk of stroke than men, yet they are usually less aware of the symptoms of stroke to watch for. For example, most women know that mammograms and self-breast exams are important in the detection of breast cancer. Yet stroke kills twice as many women each year than breast cancer and most women cannot list the symptoms of stroke to watch for.
Diagnosis of a stroke begins at home. If you are alone, you may need to recognize stroke symptoms in yourself. Similarly, if someone is with you, they will likely be the one to recognize stroke symptoms. If you even suspect a stroke, you should head straight to the emergency department. The emergency room physician will begin with a series of questions regarding your medical history. Through doing this, he or she will learn about your specific risk factors for stroke.
There are many conditions that can cause an increased risk of stroke, but the most important by far is high blood pressure, or hypertension. When blood pressure is high, it exerts a strong force against the delicate walls of brain blood vessels, which can cause them to burst open, giving way to a hemorrhagic stroke. Hypertension also causes small injuries to blood vessels throughout the body, which the bloodstream responds to in a normal way: by clotting. Although it is normal for the blood to clot in response to injury, in a blood vessel this clotting can cause both stationary clots as well as embolic (or floating) clots.
After taking a brief medical history that focuses on the previous risk factors, your doctor will examine you. He or she will be looking for a certain set of symptoms which signal a strong possibility of stroke. To see these symptoms, go back to the SYMPTOMS page for the list. Your doctor may seem to be moving your exam very quickly, despite the possibility of a condition as severe as a stroke. This is because your treatment depends on how soon after you began experiencing symptoms you arrived at the hospital. This is also why the initial phase of stroke diagnosis includes only a history and physical and not any lab tests or brain scans.
After the doctor has decided whether it is likely or not that you have a stroke, he or she may give you a certain medicine called tPA. tPA is a strong clot-buster that is only given in cases of ischemic stroke and only within a window of 3 hours after stroke onset. After 3 hours, the risk of the drug outweighs the benefit and it can no longer be given safely.
The second phase of diagnosis in stroke is more absolute than the first phase. The second phase involves lab tests as well as an MRI. Lab tests done for stroke include cardiac labs, including those testing for heart attack, electrolytes (which look at sodium and potassium in your blood, among other body chemicals), kidney function tests, how “thin” the blood is (how many clotting factors are present), and cholesterol. Tests done usually include an electrocardiogram (ECG), blood pressure, and possibly tests to measure nerve function in the limbs. The patient will usually then have an MRI so that the doctor can see a detailed picture of the brain. Sometimes an arteriogram will be done to map out the blood vessels and see where an injury might have occurred.
The most important piece of information your doctor needs to know is at what time your symptoms began. There is a 3 hour window that begins with the onset of stroke-like symptoms during which it is safe and potentially life-saving to administer a certain emergency drug. This drug is for ischemic stroke, the most common type. Ischemic strokes are due to a cut-off of blood flow to the brain due to a clot. The drug a physician can administer is called tPA. It is very powerful at breaking up blood clots, which can be good if a clot is blocking blood supply to the brain; however, it is also potentially disastrous if given to a patient having a hemorrhagic stroke. Since a hemorrhagic stroke is caused by bleeding, a clot-buster drug will only prolong and potentially increase the bleeding, thus causing the stroke to worsen. This is why it is important for your treating physician to obtain an accurate medical history for you. The doctor will use this history to assess your risk factors for stroke, and use those to make a decision regarding treatment.
If you or your loved one has a stroke that is not treatable with tPA, treatment will largely be supportive. This means physical therapy, speech therapy, and occupational therapy, depending on the area of the body affected by the stroke. If the patient is more severely affected, he or she will be hospitalized, likely in the ICU. In this part of the hospital, the patient can be closely managed so that the brain has the greatest chance of recovery.