About Stroke

What is stroke?

Stroke is the sudden onset of neurological symptoms which last longer than 24 hours and are due to either blockage of a brain, artery or bleeding, in or around the brain. Severe stroke may lead to paralysis or loss of consciousness.

Other terms that have been used to mean 'stroke' include, apoplexy and cerebrovascular accident (CVA). However, stroke or 'brain attack' are now the preferred descriptive labels.

The most characteristic feature of stroke is the onset. Symptoms and signs often have an abrupt onset, evolving within a matter of seconds or minutes although may evolve over hours. In general, improvement occurs gradually over weeks to months although dramatic improvements can be seen within a few days.

The nature and severity of the resultant neurological problems vary according to the location and size of the stroke. Hemiplegia (weakness affecting one side of the body) is probably the most well recognised sign of stroke but there are many other manifestations including speech disturbance, visual loss, double vision, memory loss, tingling and numbness, difficulty swallowing and dizziness.

What is a TIA?

Transient Ischaemic Attacks (TIAs) are transient episodes of neurological disturbance due to a vascular cause which resolve most commonly within a few minutes although completely within 24 hours. Transient ischaemic attacks must be treated as an emergency. TIAs often warn of an impending stroke and provide the opportunity for effective stroke preventing treatment to be commenced so that stroke does not occur.

Ischaemic

IIschaemic, refers to what has caused the symptoms you have. An ischaemic brain attack (stroke or TIA) happens when a blood vessel becomes narrowed or clogged, preventing blood getting through to a section of the brain. The area of brain tissue that is missing its supply of blood is called an infarction. So an ischaemic brain attack happens when not enough, or no blood flow gets through to brain tissue. This is the most common cause of brain attack.

Haemorrhage

Haemorrhage refers to the cause of the brain attack symptoms you have. A haemorrhage stroke happens when a blood vessel bursts spilling blood out into the surrounding tissue. If this happens inside the brain it is called an inter cerebral haemorrhage. If this happens on the surface of the brain it is called a subarachnoid haemorrhage.

Symptoms

Aphasis is slurred speech. This occurs when your brain attack affects the part of the brain that deals with communication. The main areas of problems my be trouble speaking, trouble understanding what others say, trouble finding words or problems with reading writing or mathematics.

Hemiplegia is the inability to move part of your body. This may occur if your brain attack has affected the area of your brain that deals with movement.

Ataxia is the inability to coordinate your movements. Ataxia can occur if your brain attack has affected the area of your brain that deals with coordination.

Paraesthesia is any change in sensation such as 'pins and needles' or numbness. This may occur if your brain attack has affected the area of your brain that deals with sensation.

Epidemiology of stroke

Stroke is a very common disease and is the third leading cause of death in Australia. Incidence exponentially increases with age so that stroke's effects are largely recognised among the elderly. About a one forth of stroke sufferers die in the acute period after stroke and about one thrird are left disabled after stroke. Cerebral infarction (stroke due to artery blockage) is much more common than haemorrhage (bleeding into the brain) and carries a better prognosis overall.

Risk factors for stroke

Important risk factors for stroke include:

• advanced age
• hypertension (high blood pressure) - risk increases with level of blood pressure
• smoking - risk increases with dose
• diabetes - level of blood glucose control is thought to be important
• atrial fibrillation (irregular heart beat)
• hypercholesterolaemia (high cholesterol level).

National Stroke Foundation for further information