When a stroke occurs, a blood vessel in the brain becomes blocked or bursts, sometimes causing permanent brain damage or even death. However, prompt treatment and follow-up care may protect brain cells and help patients lead healthy, productive lives.
Stroke is the third leading cause of death in North America, after cardiovascular disease and cancer, disabling more adults than any other condition.
There are two main types of strokes:
Ischemic Stroke -- This type of stroke accounts for approximately 80 to 85 percent of all strokes. With ischemic stroke, the blood supply to a part of the brain becomes blocked. This prevents oxygen and nutrients from reaching brain cells. Within a few minutes, these cells may begin to die.
The underlying cause for this type of obstruction is usually atherosclerosis, a condition in which plaque or fatty deposits within the wall of the arteries in the brain and neck can lead to obstruction or narrowing. These fatty deposits can cause cerebral thrombosis or cerebral embolism. With a cerebral thrombosis, a blood clot forms within the blood vessel. Cerebral embolisms are clots that can form at another location in the circulatory system, break loose from an artery wall or from the inside lining of the heart, travel through the brain's blood vessels and can lodge in an artery in the brain.
Hermorrhagic Stroke -- With hemorrhagic stroke a blood vessel within the brain leaks or ruptures and bleeds into the surrounding brain tissue. This is called an intracerebral hemorrhage. The blood can accumulate and exert pressure on the surrounding tissue.
High blood pressure is a common cause of intracerebral hemorrhage. In a subarachnoid hemorrhage, blood leaks under the lining of the brain. This is often caused by a small bubble on an artery known as an aneurysm.
Common symptoms of stroke include:
If you are experiencing any symptoms of stroke, you should go to a doctor or hospital right away, preferably by dialing 911.
Transient Ischemic Attack (TIA) -- Although strokes typically occur without warning, some people may feel a temporary numbness, weakness or tingling in one arm or leg, or problems with speech, vision or balance before the actual onset of the stroke. This occurs because the blood supply to the brain is temporarily reduced, called a transient ischemic attack (TIA). These episodes usually last a few minutes to hours and may not cause immediate permanent injury to the brain. However, a TIA is a sign that the risk of a permanent stroke is great. TIA is an emergency. Patients with TIAs should be seen right away, just like those with stroke symptoms that don't go away.
Risk factors for stroke that cannot be changed:
Risk factors for stroke that are modifiable:
It is critical to come to the hospital immediately if you experience a stroke because treatments might reduce or completely reverse the brain injury from stroke. These treatments must be given within the first few hours of stroke symptoms. These treatments include administration of a t-PA — a drug that opens blocked blood vessels — or devices to remove the clot from the brain using a catheter (thrombolysis).
Post-stroke prevention may involve the administration of antiplatelet drugs such as aspirin, control and reduction of hypertension, the use of statins, and in selected patients with carotid endarterectomy, the use of anticoagulants.
Treatment to recover any lost function is stroke rehabilitation, involving health professions such as speech and language therapy, physical therapy and occupational therapy.