A stroke could be called a brain attack, as it causes damage to the brain. There are some types of stroke: ischemic, hemorrhagic, and transient ischemic attack. Understanding how strokes occur, and knowing the symptoms, is key to survival and recovery.
What is an ischemic stroke?
The most common type of stroke, an ischemic stroke occurs when a blockage prevents the flow of blood to the brain. This is similar to what happens in a heart attack and accounts for 87 percent of all strokes. The blockage is caused by a blood clot which can be formed in one of three ways.
Firstly, fatty build up in an artery in the brain catches sticky blood platelets as the flow by, creating a clot. This clot can build up enough to block blood flow, or break off and travel until it becomes lodged in the narrowing artery.
Secondly, the fatty build up from an artery in another part of the body breaks off, forms a clot, and travels to the brain where it becomes lodged in a narrowing artery.
Finally, a clot can be formed in the heart when an abnormal heart rhythm, called Atrial Fibrillation, causes the blood to pool and clot. This clot can then travel from the heart to the brain. The only way to treat an Ischemic stroke is to remove or dissolve the clot. Tissue plasminogen activator (tPA) is known as a “clot-buster” and if given within 3 hours of the onset of stroke symptoms can greatly improve the chances of recovery. In some patients, tPA can be administered up to 4.5 hours after a stroke begins. Acting quickly when a stroke occurs is essential. If tPA is not an option, a specially trained surgeon can attempt to remove the clot or dissolve it directly by sending a catheter through the artery.
What is a Hemorrhagic stroke?
Hemorrhagic strokes are less common, accounting for only 13 percent of all strokes. This type of stroke, also known as a brain bleed, is caused when a weakened blood vessel in the brain breaks and bleeds. The blood collects and puts pressure on the surrounding brain tissue, causing damage. Weakened blood vessels in the brain are caused by either an aneurysm or an arteriovenous malformation (AVM). An aneurysm looks like a balloon on the side of a blood vessel and is the result of a weakened area of the vessel. Left untreated, the aneurysm can be stretched until it breaks, causing bleeding in the brain and a stroke. An AVM is a group of abnormally formed blood vessels in the brain. These abnormal vessels are weak and can rupture, causing bleeding and a stroke. Regardless of the cause, bleeding in the brain must be stopped surgically to prevent further brain damage. Some bleeds can be stopped with an endovascular procedure, using a catheter through the artery. Others require brain surgery.
What is a transient ischemic attack?
Often called a “mini-stroke” a transient ischemic attack (TIA) should not be taken lightly. A TIA may look and act exactly like an ischemic stroke. It is caused by a clot, blood flow is blocked, and stroke symptoms occur. However, a TIA is temporary, usually less than five minutes. At the end of the attack, there is no permanent damage to the brain. The clot dissolves on its own. There is no way to predict if a clot will dissolve or not and the longer it is in place, the more damage can occur. A TIA is a medical emergency and should be evaluated and treated even if the symptoms disappear. Having a TIA increases the risk of ischemic stroke. About one-third of those who have a TIA will have a permanent stroke within a year.
What are the symptoms of stroke?
In all three types of stroke, the symptoms are the same:
- Sudden severe headache.
- Sudden drooping, numbness or weakness on one side of body, face, arm or leg.
- Sudden trouble speaking.
- Sudden confusion.
- Sudden difficulty seeing out of one eye, or both eyes.
- Sudden trouble walking, loss of balance or coordination.
- Sudden dizziness. Experiencing any one of these symptoms is cause to call 911. Act quickly and take note of the time symptoms began.
Understanding stroke and the symptoms of stroke can make the difference between survival and recovery and death or permanent disability.