There are a range of different illnesses and injuries that can specifically affect a person’s conscious state, causing either sudden or progressive loss of consciousness. The stroke is habitually a chronic cardiovascular disease, lasts over a prolonged period of time and sometimes causes a long-term change in the body. It is the third- major cause of death in Australia after heart disease and cancer and the risk of developing it is higher in those who smoke, have high blood pressure, high cholesterol levels, are diabetic and drink excessive amounts of alcohol.

A stroke is said to occur when the arterial blood flow leading the blood supply to a certain part of the brain is suddenly disrupted and becomes either blocked or ruptures. The brain cells affected may be deprived of sufficient oxygen to function properly as blood carries oxygen and nutrients to the neurons (nerve cells) in the brain, so when the blood flow stops, the cells begin to die. As a result, the functions of the body controlled by the nerve cells may lose their ability to function and receive transmitted messages.

Brain cells usually die within an hour of the onset of a stoke but may survive for several hours, especially when the blood supply to the brain has not been stopped completely. Sometimes the interruption resolves itself quickly and, if this occurs within about an hour, it is known as a mini- stroke or a transient ischaemic attack (TIA). A mini stroke is an early warning sign of a more serious stroke where 30% of stroke patients will have a small warning episode of a TIA and sufferers will experience similar symptoms to a normal stroke such as the sudden loss of function of a particular part of the body.

The difference between a TIA and a stroke is that in a TIA the symptoms disappear completely within 24 hours. In 75% of cases the symptoms clear within one hour, often within only a few minutes, because the blockage in the artery clears itself very quickly before the affected brain tissue has died.  30% of people have damage evident on sensitive brain imaging techniques such as MRI after the mini- stroke.

The most common cause of a stroke is where the artery becomes blocked, usually by a blood clot or plaque. This generally tends to occur in older aged people and the risk is increased by factors such as high blood pressure, smoking and poor diet. The other main cause of stroke occurs when a blood vessel tears and bleeds. This may occur as a result of injury or a weakness in the wall of the blood vessel and high blood pressure.

Though each stroke is different depending on the casualty. The symptoms and effects vary according to the type of stroke (ischaemic or haemorrhagic), the part of the brain affected and the size of the damaged area.

An Ischaemic Stroke occurs when an artery carrying blood to part of the brain is blocked. The brain needs the constant supply of oxygen and glucose that the blood brings. If this blood supply is blocked for more than a few minutes then that part of the brain stops working properly and brain tissue at the centre of the area affected begins to die. If the blockage is not cleared within a few hours then that all the part of the brain supplied by the blocked vessel may die; that is, it permanently ceases to work properly. This is called brain infarction. Ischaemic strokes are the most common type of stroke, occurring more than five times as often as haemorrhagic strokes.

A Haemorrhagic Stroke occurs when a blood vessel ruptures within the brain or into the space surrounding the brain. Blood in the artery is under pressure and so, as it spurts out, it tears some of the soft brain tissue and forms a large clot (or haematoma) that squashes the surrounding brain. Brain tissue on the rim of thein and around the clot may therefore die.

Conclusively the nature of the stroke and the specific abilities that are lost or affected by the stroke depend on the extent of the cell death and where in the 4 main parts of the brain the stroke happened.

The right hemisphere controls: -left side of the body

-analytical and perceptual tasks such as judging distance, size, speed, position -short-term memory

The left hemisphere controls: -right side of the body

-speech and language -memory

The cerebellum controls: -balance and coordination

The brain stem controls: -life-support functions such as breathing, blood pressure and heartbeat

-eye movements -hearing -speech

-swallowing

Depending on the severity of the stroke, victims may or may not experience any or all losses of the above functions.

There are sometimes quite specific warning signs of an impending stroke. By recognising the warning signs and taking action, you may be able to prevent a stroke or reduce its severity. It is important to be able to recognise the warning signs in order to get medical help as quickly as possible.

The first signs that someone has had a stroke are very sudden. Symptoms include:•numbness, weakness or paralysis on one side of the body (signs of this may be a drooping arm, leg or lower eyelid, or a dribbling mouth) •slurred speech or difficulty finding words or understanding speech •sudden blurred vision or loss of sight •confusion or unsteadiness •a headache, usually severe and with fast onset•reduced level of consciousness or unconsciousness•unequal pupil.

Use the Face-Arm-Speech Test (FAST)Three simple checks can help you recognise whether someone has had a stroke or mini-stroke (transient ischaemic attack - TIA).

F. Facial weakness: Can the person smile? Has their mouth or an eye drooped?A. Arm weakness: Can the person raise both arms?S. Speech problems: Can the person speak clearly and understand what you say?T. Test these symptoms.

First aid for a victim suffering from a stroke is limited to supportive care until medical assistance arrives. Caring for the victim with a calming presence and collecting important medical data to pass onto emergency medical personnel is very important. When it comes to treatment, the wait- and- watch attitude is best appropriate.

Primary management techniques to help preserve the life of the casualty when experiencing a stroke includes:

If responsive:• Call an ambulance• Reassure the victim as well as encourage them not to move and stay with them until the ambulance arrives• Help the victim into a position of comfort and lay the victim down with their head and shoulders slightly elevated. This will reduce blood pressure on the brain. • Provide supplemental oxygen if able• Never give a suspected stroke victim anything to eat or drink. Their throat may be paralyzed restricting them from the ability to swallow.

If unresponsive:

•Call the ambulance.•Conduct a primary survey – DRABCD.Danger- check for danger to self, bystanders and casualty. Response- Use the ‘COWS’ method (Can you hear me? Open your eyes. What’s your name? Squeeze my hand.)Airway- Check for signs of life and clear mouth of foreign objectsBreathing- give 2 rescue breathsCompression- 30 compressions at a rate of 100 per minute followed by 2 rescue breaths. Defibrillation- if one is available attach as soon as possible and follow the prompts. •Recovery position.

Lippmann, J. and Natoli, D. (2006) First Aid. Royal Life Saving- Australia

Health Encyclopedia (2008) Stroke- symptoms, treatment and prevention

http://www.healthscout.com/ency/68/136/main.html American Stroke Association (2008) What is a

stroke?http://www.healthscout.com/ency/68/136/main.html The stroke association (2008) What is a stroke?http://www.stroke.org.uk/information/what_is_a_stroke/index.html

Brain foundation Australia (2008) The Strokehttp://www.brainaustralia.org.au/stroke/what_is_a_stroke_