Strokes or cerebrovascular accidents (CVAs) are defined as disorders involving sudden decrease in blood supply to the brain that causes problems in brain functions. The neurological damage resulting from stroke can lead to severe complications, including death. It is one of the more commonly seen neurovascular events in the elderly and a common cause of disability and death in seniors.
Stroke can be of following types:
- Ischemic stroke: Most common type, seen in 80% stroke patients. Results from decreased blood supply to the brain due to blockage in blood vessels.
- Hemorrhagic stroke: Seen in 20% patients. Results from rupture of a blood vessel or an abnormal blood vessel.
- Transient ischemic attack (TIA): Also called mini stroke. Symptoms last for less than an hour but there is no permanent effects.
The following symptoms may be present during or after a stroke:
- Paralysis of the arms and legs and the face
- Difficulty talking
- Disturbed vision in one or both eyes
- Dizziness or loss of coordination and balance
Decreased blood supply to the brain deprives the brain of oxygen and nutrients. This causes the brain cells to die, which results in symptoms of stroke.
Causes of different types of strokes can be grouped as:
- Ischemic stroke: Narrowing or blocking of brain arteries causes severely reduced blood flow to the brain. Ischemic strokes may be further classified as:
– Thrombotic stroke, in which a blood clot (thrombus) blocks the arteries supplying blood to the brain. Such clots may be made up of fatty deposits called plaques.
– Embolic stroke, in which a blood clot or debris (embolus) formed somewhere in the body reaches and gets lodged in the narrow brain arteries.
- Hemorrhagic stroke: Hemorrhagic stroke results from rupturing of a blood vessel in the brain. Many conditions like unregulated high blood pressure, abnormal balloon-like structures in the walls of blood vessel (aneurysms) or abnormal tangle of thin-walled blood vessels (arteriovenous malformation or AVM) can result in hemorrhagic stroke.
- Treatment aims at quickly restoring blood flow to the brain.
- Clots may be removed mechanically or are dissolved with the help of clot-busting drugs or thrombolytics (like aspirin, heparin, clopidogrel, warfarin, tissue plasminogen activator or TPA).
- In a surgical procedure called carotid endarterectomy, fatty deposits (plaques) from the carotid arteries are removed.
- In an angioplasty, a balloon is attached to a catheter and inserted into the narrowed carotid artery. Once inflated, the balloon keeps the artery open and wide.
- Treatment aims at controlling the bleeding and reducing pressure in the brain.
- Some patients might be taking warfarin or anti-platelet drugs (like clopidogrel) to prevent blood clots. In such cases, drugs or substances are given to counteract their effects.
- Drugs (like nicardipine, nimodipine) are recommended to lower pressure in the brain (intracranial pressure), to regulate blood pressure, and to prevent seizures.
- Surgery is performed in the cases of large area of bleeding. Surgery removes the blood and relieves pressure on the brain.
- Base of an aneurysm can be clamped surgically. This will stop blood flow to it and prevent aneurysm rupture.
- Smaller and easily accessible AVMs can be removed surgically.