The most common risk factors for strokes are:
- high blood pressure
- high cholesterol
- increasing age
Other causes can be heart valve disease, patent foramen ovale and heart rhythm disturbances like atrial fibrillation. If stroke occurs in younger people, say earlier than fifty years of age then other risk factors which are not as common, are considered. These could be inherited predispositions to abnormal blood clotting, ruptured aneurysms, the use of illegal drugs such as amphetamines or cocaine.
A genetic predisposition to stroke could be a rare condition known as homocystinuria. This occurs when there is too much of a chemical called homocystine in the body. Scientists are currently researching whether a person who has a non-genetic occurrence of high levels of homocystine could be predisposed to a stroke too.
A (TIA) Transient Ischemic Attack
This is a mini-stroke, a short lived stroke that as it resolves, gets better. It is less than 24 hours and is a temporary impairment of brain function because of loss of blood supply. The portion of the brain that suffers the loss of function then causes the part of the body it is responsible for to lose control. A clot that suddenly forms within a blood vessel, known as thrombosis causes a loss of blood to the brain. A clot can form somewhere else in the body then moves and wedges itself in an emboli (artery of the brain). Sometimes a bleed or spasm can cause a mini-stroke.
TIAs can develop very quickly and others slowly. All TIAs (mini-strokes) resolve themselves within a 24 hour period. It takes a longer time to resolve a stroke and total function may never return which obviously can mean a more serious and permanent problem. With mini-strokes, they almost always last just a few minutes and they should be treated as urgently and seriously as strokes to help prevent them occurring again or future strokes. Mini-strokes can just happen once or multiple times. They can also happen before a permanent stroke so they should be treated as an emergency as full resolution and function is not guaranteed.
There is a condition known as amaurosis fugax which is temporary loss of vision caused by a TIA from a clot in a blood vessel which supplies the retina of the eye. It causes a sensation that is like having a curtain come down over one eye. If a clot develops in the largest blood vessel that supplies the brain known as the carotid artery then this can mean that movement and function down one side of the body can be impaired or permanently damaged. The side of the body that is affected is the opposite side of the brain that the TIA has occurred. Patients that have suffered a mini-stroke like this can experience double vision, dizziness, weakness or paralysis of their arm, leg or face or the one whole side of the body. Also loss of balance, an inability to speak or understand what people are saying to them can be experienced.
In the America, strokes are the 3rd largest causes of death (after heart disease and all types of cancer). They cause a huge loss to the sufferer in terms of their independence and quality of life. Often the patient’s family and friends have to take on care-giving roles.
The symptoms of strokes will be different according to the area of the brain affected and the quantity of brain tissue which has been damaged by the brain cells being deprived of oxygen. There are small strokes known as silent strokes because they do not cause any symptoms but still cause damage to the tissue of the brain.
There are five major signs of stroke according to The U.S. National Institute of Neurological Disorders and Stroke (NINDS):
- Spontaneous numbness or weakness of the patient’s face, arm or leg. This is usually just on one side of the body. Complete or partial loss of movement and/or sensation. Sometimes a tingling can be felt in the area affected.
- The patient can suddenly find it difficult or impossible to speak or understand commands. The weakness in the facial muscles can cause the patient to drool.
- Visual impairment in one or both eyes can occur.
- A very sudden head ache which is severe and without a known cause.
- Trouble walking, dizziness, loss of balance or coordination is common.
By Eirian Hallinan