Different Types of Strokes
Published: 23 June 2020
Published: 23 June 2020
You might automatically envision mobility difficulties and hemiplegia, or perhaps swallowing problems, or maybe even being unable to speak and communicate.
In reality, there are different types of strokes and therefore, different resulting symptoms. It is important to know exactly what type of stroke your patient has experienced in order to predict some of these symptoms.
A stroke, also known as a cerebrovascular accident, is the interruption of blood supply to part of the brain, resulting in acquired (non-traumatic) brain injury (Mayo Clinic 2020; Brain Injury Association of America 2018).
The disruption of blood flow deprives the affected area of the brain from the nutrients and oxygen it needs to survive, resulting in cell death (Mayo Clinic 2020).
There are two main types of stroke: ischaemic and haemorrhagic.
An ischaemic stroke occurs when a thrombus or embolus impairs cerebral blood flow. It is the most common type of stroke, accounting for about 87% of cases (ASA 2019).
A thrombotic stroke is caused by a build-up of fatty deposits in the arteries, narrowing the lumen and causing a thrombus to form. This thrombus may then occlude the artery (The Internet Stroke Center n.d.a).
An embolic stroke occurs when an embolus forms in the circulatory system (usually in the heart or large arteries of the upper chest and neck), dislodges and is carried to the brain, where it occludes a cerebral blood vessel (ASA 2019).
A haemorrhagic stroke occurs when there is a rupture in a cerebral blood vessel that causes bleeding in the brain (ASA 2018a).
The main cause of haemorrhagic strokes is hypertension, but they can also be brought on by anatomical defects such as aneurysms, arteriovenous malformations (AVMs) or degenerative changes occurring in arterial walls (Harvard Medical School 2019).
An aneurysm occurs when a weakened area of a blood vessel enlarges and ‘balloons’ out. This section of the blood vessel may continue to weaken until it eventually ruptures and bleeds into the brain (ASA 2018b).
It is estimated that about five per cent of Australians have an aneurysm, but many will not rupture (myDR 2019).
Arteriovenous malformations (AVMs) occur when there is a cluster or tangle of abnormally formed blood vessels. These blood vessels bypass normal brain tissue and divert the blood from the arteries to the veins. If these AVMs rupture they then cause bleeding (Mayo Clinic 2019).
Symptoms of an AVM will vary depending on its location (Mayo Clinic 2019).
The manifestation of a stroke will depend on many factors. When a stroke occurs, areas of the brain are deprived of their oxygen supply, causing necrosis of cerebral tissue and resulting in neurological deficits.
The deficits that may present will depend on the area of the brain involved (Mayo Clinic 2020).
When a stroke occurs, it is important to take note of which brain hemisphere it has occurred in, as this will suggest the neurological deficits that have potentially occurred.
Generally, the patient will experience hemiplegia on the opposite side of the area of stroke. For example, if they had a stroke in the left hemisphere of their brain, they will experience right-sided weakness or hemiplegia (Eyvazzadeh 2020).
There are other potential effects that depend on which hemisphere the stroke occurred in:
(Allina Health 2018)
(Allina Health 2018)
A middle cerebral artery (MCA) stroke occurs when the middle cerebral artery, which supplies the frontal lobe and lateral surface of the temporal and parietal lobes with blood, becomes blocked (Nogles & Galuska 2020).
It is important to note that individuals who have experienced the same type of stroke will often display different symptoms depending on precisely where and how much of the brain was deprived of oxygen and where cerebral tissue necrosis has occurred.
This is especially important to remember for those who have had an MCA stroke, as the middle cerebral artery supplies such a vast area of the brain that the deficits are dependent on the areas most damaged.
A MCA stroke can have many implications for the individual. These include:
(Nogles & Galuska 2020; The Internet Stroke Center n.d.b)
The anterior cerebral artery supplies blood to most of the anterior section of the interhemispheric cortical surface of the frontal and parietal lobes (Physiopedia 2016).
The deficits left following this type of stroke may include:
(Jauch 2020; Das & Saadabadi 2020)
Strokes in the posterior cerebral artery will affect the temporal and occipital lobes, impacting the sight of the individual (Kyubu, Tadi & Dossani 2020).
Individuals who have experienced this type of stoke will potentially experience blindness in half their vision field (hemianopia) or the inability to perceive colours (Kyubu, Tadi & Dossani 2020).
They may also experience dyslexia, memory deficits, aphasia or pupillary dysfunction (Kyubu, Tadi & Dossani 2020).
About one in four stroke survivors will experience another one (ASA 2019).
This is quite significant considering that a second stroke is often more severe than the first (Singapore National Stroke Association 2016).
Therefore, implementing stroke prevention strategies, providing education and decreasing known risk factors for the individual are essential in the treatment following a stroke.
Question 1 of 3
Which is the most common type of stroke?
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