A stroke, sometimes referred to as a cerebral attack, is a sudden neurological deficit of vascular origin (where the blood supply to part of the brain is interrupted).
The term ‘accident’ is used to emphasise the sudden, even abrupt, onset of symptoms or signs, although in fact it is actually an illness with internal causes.
Causes
A stroke can be caused by:
- a blockage of a cerebral artery (cerebral infarction) caused by an arterial spasm, an atherosclerotic plaque (cerebral thrombosis) or a blood clot that has blocked the artery (cerebral embolism). This is the most common cause (85 per cent) and can be treated with new, highly effective treatments if administered early (within 2 to 3 hours of the onset of symptoms);
- A cerebral haemorrhage, most commonly caused by the rupture of a blood vessel (in patients with high blood pressure) or a vascular malformation (such as an aneurysm). Tumours and various clotting disorders can also lead to a cerebral haemorrhage.
A transient ischaemic attack (TIA) is defined as a condition in which the blockage in a cerebral artery resolves spontaneously, with the symptoms disappearing more or less quickly depending on the duration of the blockage.
The symptoms are the same as those of a stroke, but they last from a few seconds to a few minutes – never more than an hour – before things return to normal.
A TIA can go unnoticed and be mistaken for a simple bout of feeling unwell. A TIA is a warning sign; it may foreshadow a full-blown stroke and carries the same risks.
Risks & Consequences
A stroke causes a reduction in, or even a sudden cessation of, blood flow to part of the brain. The neurological impairment caused by a stroke depends on the size and location of the affected blood vessel.
The interruption of blood flow leads to ischaemia in the nerve cells, suddenly depriving them of oxygen and glucose, which causes them to deteriorate and then die within a few minutes.
In the event of a haemorrhage, in addition to vascular damage, the accumulation of blood (haematoma) in the space between and around the meninges and the brain compresses the nerve cells and causes neurological symptoms of varying severity, depending on the extent of the haemorrhage.
A stroke is a serious condition, with consistently severe consequences, carrying a risk of death or serious long-term effects. Stroke is the leading cause of disability in adults and the third leading cause of death.
Signs
A stroke may be suspected during a life-threatening emergency assessment, as it usually occurs suddenly:
- loss of consciousness or impaired consciousness;
- motor impairment affecting one entire side of the body (right or left).
During the follow-up assessment, a conscious victim may display one or more of the following specific signs:
- a distortion of the mouth: the victim shows facial asymmetry, which is even more evident when asked to pull a face;
- weakness or numbness on one or both sides of the body: when the victim is asked to raise and extend both arms and hands in front of them, one arm and/or hand (or both) cannot be raised or cannot be held in that position and falls back more or less quickly;
- a difficulty with language or comprehension: when the victim is asked to repeat a sentence, they have difficulty speaking or understanding.
These three signs must always be checked for. They are commonly known as FAST, or the ‘Face, Arm and Speech test’.
They may also be accompanied by:
- a reduction in or loss of vision in one or both eyes;
- a severe, sudden and unusual headache with no apparent cause;
- a loss of balance, unsteadiness when walking, or unexplained falls.
Although all these signs are transient and self-limiting, they must be thoroughly investigated, as the severity of the condition and the course of action to be taken remain the same.
In the event of these signs, the first-aider should find out, or ask the victim or their family to clarify, the following:
- the time when the marks appeared and the time when the victim was last seen without the marks;
- the presence of identical neurological symptoms within the previous 24 hours;
- a history of seizures;
- the presence of a fever;
- the victim’s level of mobility: is the victim normally independent or confined to a wheelchair or bed;
- the presence of risk factors:
- high blood pressure and cardiovascular disease;
- diabetes or high cholesterol;
- obesity, smoking;
- anticoagulant treatment.
- specific medical history which must be known in order to provide care for the victim in a specialist setting:
- a recent operation,
- if the patient has a pacemaker or has a contraindication to undergoing an MRI scan.
During the follow-up assessment, it is essential to measure capillary blood glucose levels. This is because hypoglycaemia can mimic a stroke and cause one or more of the symptoms listed above. It is therefore essential to check for and correct hypoglycaemia before concluding that the signs indicate a stroke.
Principle of emergency response
- Seek immediate medical advice and follow the instructions given.
- Place the victim in the recovery position.
- monitor the victim and carry out the necessary first aid.