03 Nov Stroke Fact Sheet
A stroke happens when blood cannot supply oxygen and important nutrients to your brain cells. There are two main types of stroke:
- Ischemic, caused by the blockage of an artery by a blood clot or cholesterol plaque; and
- Hemorrhagic, caused by bleeding within the brain or the delicate area within the skull that surrounds it.
Both types cause cell death, resulting in parts of the brain not functioning properly.
Signs and symptoms often appear soon after a stroke has occurred. If they last less than two hours, the blockage has been temporary and the condition is known as a transient ischemic attack (TIA) or mini-stroke. However, the symptoms of a stroke can be serious and permanent, and patients suffering from stroke or a TIA often require emergency care.
Symptoms may include:
- an inability to move or feel on one side of the body;
- problems understanding or speaking;
- loss of vision to one side; and
- in some cases of hemorrhagic stroke, severe headache.
How do you know if someone is having a stroke? The Stroke Foundation recommends the F.A.S.T. test as an easy way to remember the most common signs of stroke.
Using the F.A.S.T. test involves asking these simple questions:
- Face Check their face. Has their mouth drooped?
- Arms Can they lift both arms?
- Speech Is their speech slurred? Do they understand you?
- Time Is critical. If you see any of these signs call 000 straight away.
Ischemic strokes are caused by decreased blood supply to part of the brain due to:
- a blood clot forming locally and obstructing a blood vessel;
- obstruction caused by a blood clot or cholesterol plaque that has travelled from another part of the body;
- a general decrease in blood supply, sometimes associated with shock; or
- a blood clot in the dural venous sinuses which drain blood from the brain.
Hemorrhagic strokes are caused by:
- bleeding within the brain itself, caused by an artery bursting and flooding surrounding tissue with blood; or
- bleeding outside the brain tissue but still within the skull.
Risks and complications
The main risk factor for stroke is high blood pressure. Other risk factors include tobacco smoking, obesity, high blood cholesterol, diabetes mellitus, a record of a previous TIA, and atrial fibrillation. Users of stimulants such as cocaine and methamphetamine are at a high risk of ischemic strokes. Age is also a factor, with two thirds of strokes occurring in people over 65.
Long-term complications associated with stroke may include pneumonia or loss of bladder control. For patients with severe brain damage, complications may include persistent vegetative state (PVS), leaving them in a state of partial arousal rather than true awareness.
Diagnosis is usually based on a physical examination, supported by medical imaging such as a CT scan or MRI scan. A CT scan can rule out bleeding, but may not rule out the blockage of an artery which typically fails to show on a CT scan early on. Other tests such as an electrocardiogram and blood tests are used to determine risk factors and rule out other possible causes. However, there is not yet a commonly used blood test for stroke diagnosis itself.
Surgery may be the best option, and a patient’s suitability for surgery will be based on their age, gender, and the degree of stenosis (the narrowing or blockage of the arteries). Surgery is most efficient when not delayed too long.
Treatment to recover lost function is another part of the picture. Known as stroke rehabilitation, this ideally takes place in a stroke unit when such a facility is available.
Stroke prevention includes decreasing risk factors which may involve making lifestyle adjustments including diet and exercise, and avoiding the use of stimulants.
Other preventative measures may include the use of aspirin and statins. Surgery to open up the narrowed arteries to the brain is an option for some patients, while warfarin is often prescribed for those with atrial fibrillation.