Stroke

Ischemic stroke

An ischemic stroke occurs when the brain’s blood vessels become narrowed or blocked, severely reducing the blood flow. Blocked or narrowed blood vessels are caused by fatty deposits that build up in blood vessels (also known as thrombosis), or by blood clots or other debris that travel through the bloodstream and lodge in the blood vessels in your brain (also known as an embolism).

Haemorrhagic stroke

Haemorrhagic stroke occurs when a blood vessel in or on the surface of the brain leaks or ruptures. When it happens in the brain it is referred to as an intracranial haemorrhage. When it happens on the surface of the brain it is referred to as a subarachnoid haemorrhage. Brain haemorrhages can result from many conditions that affect the blood vessels, including:

• Uncontrolled high blood pressure
• Overtreatment with blood thinners (anticoagulants)
• Bulges at weak spots in your blood vessel walls (aneurysms)
• Protein deposits in blood vessel walls that lead to weakness in the vessel wall (cerebral amyloid angiopathy)
• The rupture of an abnormal tangle of thin-walled blood vessels (arteriovenous malformation).

A stroke is not necessarily a major event, and may not always be recognisable as a stroke. It may present as someone stumbling or having a moment of blankness. It is vital to treat a stroke immediately and call an ambulance.

The FAST test is an easy way to recognise and remember the signs of stroke. Using the FAST test involves asking three 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 

Time is critical. If you see any of these signs call an ambulance straight away.

The effects of a stroke vary widely for each stroke patient depending on which part of the brain is affected. Different parts of the brain are responsible for thought processes, comprehension, movement and our senses. The extent of blood shortage also determines the effect of the stroke.

A stroke may generally result in:

• paralysis
• loss of feeling
• communication difficulties
• visual problems

and many other issues depending on which part of the brain is affected:

Left hemisphere effects

A stroke in the left hemisphere of the brain may result in:

• some degree of paralysis on the body’s right side
• lost or disturbed (hot or cold, acute or diminished pain) feeling on body’s right side
• right field of vision deterioration
• loss of speech or comprehension (Aphasia), and other speech problems including Echolalia (exact repetition of a word or sentence just spoken by another person), perseveration (continual repetition of a word or phrase), inappropriate use of “yes and “no” and inability to discriminate between left and right
• inability to name objects that can be recognised and used

Right hemisphere effects

A stroke in the right hemisphere of the brain may result in:

• Some paralysis on the body’s left side
• lost or disturbed (hot or cold, acute or diminished pain) feeling on body’s left side
• left field of vision deterioration
• difficulty expressing emotions
• inability to read facial expressions or voice tone in other people
• difficulty speaking, slurred speech or incessant and repetitive talking
• spatiotemporal difficulty with a tendency to get lost if left alone

Although the left and right hemispheres of the brain are usually affected, damage in the lower levels of the brain can also occur. The brain stem and cerebellum are involved in maintaining vital body systems, reflexes and balance.

A stroke in the brain stem can cause:

• unconsciousness
• inability to speak
• paralysis
• unstable pulse
• blood pressure fluctuations
• difficulty swallowing or breathing
• difficulty with eyeball movement.

A stroke in the cerebellum can cause:

• double vision
• dizziness and loss of balance
• lack of coordination in the hands
• slurred speech.

Emergency treatment for stroke depends on whether it is an ischemic or haemorrhagic stroke.

Ischemic stroke

To treat an ischemic stroke, blood flow must be quickly restored. This can be done with:

Medication. An injection of a drug called alteplase, or Activase Therapy, has to be given within hours of when symptoms first started. This drug restores blood flow by dissolving the blood clot causing the stroke. Quick treatment not only improves the chances of survival, it may also reduce complications.

Endovascular procedures. Ischemic stroke can be treated by delivering medications directly into the blocked blood vessel, or by removing the clot with a stent retriever.

Hemorrhagic stroke

Emergency treatment of hemorrhagic stroke focuses on controlling the bleeding and reducing pressure in the brain caused by the excess fluid.

Treatment options include:

Medication. Drugs that counteract any anticoagulants or blood thinners that have been taken can be used. There are also drugs available to lower the pressure in the brain, lower the blood pressure, prevent spasms of the blood vessels, and prevent seizures.

Surgery. If the area of bleeding is large, surgery to remove the blood and relieve pressure on your brain may be required. Surgery may also be used to repair blood vessel problems associated with.

Although the brain does not regenerate brain tissue that dies after an embolism or thrombosis, it will repair damaged tissue, and it will find ways to make new connections to replace those that have been lost. After a haemorrhage the brain may also regain some function after the pressure caused by bleeding has decreased.

Recovery after a stroke depends on many factors, including:

• type and severity of the stroke
• parts of the brain involved
• extent and nature of the damage
• existing medical problems
• type and timing of treatment and rehabilitation.

Recovery usually involves a lot of relearning of activities such as walking and talking. Relearning can be complicated as many people have trouble concentrating after a stroke. Attention can be affected markedly by a stroke in the front right side of the brain and can lead to slower rehabilitation as learning may be impaired.

Rehabilitation aims to:

• help you understand and adapt to your difficulties
• regain skills
• prevent secondary complications
• help you and your family to come to terms with the stroke.

Knowledge of rehabilitation following a stroke is growing steadily, as neurologists and neuropsychologists experiment with using mirrors or offset treadmills to retrain muscle groups and nerve pathways. As with any other form of brain injury, the key is understanding, persistence and a close relationship with the medical team.