What Is An Ischaemic Stroke

A stroke is a debilitating and life-threatening medical emergency that happens due to a compromised blood supply to the brain, resulting in damage to brain cells. It can have a significant impact on one’s life and family as well as on the community. That is why it is very important to recognise possible signs and symptoms and call for professional help without any delay.

The impact of a stroke on individuals depends on the type. There are 2 main causes of stroke: haemorrhagic and ischaemic. Blood supply is interrupted due to bleeding from a brain vessel in a haemorrhagic stroke, whereas it is affected due to a blockage in an ischaemic stroke.

An ischaemic stroke is the most common type of stroke, accounting for 85% of all cases and will be the focus of this article.

Given the fact that an ischaemic stroke has a substantial amount of impact on public health, we aim to shed light on this important topic to increase the knowledge and awareness of the public.  

Overview

A stroke or, in medical terms, cerebrovascular accident might result in death or compromise the quality of life, leaving individuals deprived of abilities to cope with activities of everyday life. 

The long-term outcome following a stroke depends on the type and severity. A transient ischaemic attack (TIA), also known as a mini-stroke, is characterised by stroke symptoms that resolve in less than 24 hours. Generally, this type has the best long-term outcomes.

According to WHO, 15 million people worldwide suffer a stroke every year. Around 5 million of these lose their lives, and another 5 million suffer from permanent disabilities as a result of stroke. Although stroke affects the elderly more, it can also occur in young adults and even in children with certain underlying conditions.

Causes of an ischaemic stroke

Ischaemia is a disruption in blood flow sufficient enough to compromise the normal function of brain cells. Due to the high sensitivity of brain tissue to ischaemia, even brief reductions in blood flow might trigger a complex sequence of events that ultimately end up in the death of the affected cells. 

Vulnerability to ischaemia varies between different regions of the brain. The grey matter of the brain has a lower threshold for ischaemic cell damage compared with white matter.¹

Compromised blood supply in ischaemic stroke might be due to a blood clot, a blocked artery, and decreased blood supply all over the body. Atherosclerotic changes, inflammatory mechanisms and gene disorders may play a role in the development of stroke.²

An ischaemic stroke has a complex way of showing itself and consists of several processes, some of which include cellular imbalances and toxicity. These events happen in relation to each other and subsequently cause cell death.

Signs and symptoms of an ischaemic stroke

An ischaemic stroke might present with a variety of symptoms. Most commonly, patients can wake up with symptoms or have a sudden onset of symptoms. The most common physical findings are weakness on one side of the body and difficulty speaking.² 

The most common signs and symptoms of an ischaemic stroke are:²

• Arm weakness
• Leg weakness
• Speech disturbance
• Facial weakness
• Pins and needles in an arm
• Pins and needles in a leg
• Headache
• Dizziness  
• Difficulty swallowing, speaking or walking

Strokes affecting the regions behind the head, also known as posterior circulation stroke, mostly present with dizziness and, therefore, are hard to tell apart from other possible diagnoses due to dizziness being an uncommon symptom of a stroke.¹⁰ Other possible symptoms that posterior circulation stroke might present include balance problems, slurred speech, nausea and vomiting, and nystagmus (repetitive and involuntary movement of the eyes).^2,10

The main symptoms of a stroke can be memorised with a mnemonic called FAST: 

• Facial weakness - mouth or eye may droop, and smile may be affected
• Arm weakness and numbness - unable to move or lift the arms
• Speech disturbance - slurred speech or inability to talk
• Time - Whenever you or anyone around you experience any of the possible symptoms or signs of stroke, it is time to call 999 without losing time

Diagnosis

Telling a TIA and a stroke apart is impossible without further investigation. For this reason, a rapid assessment of all patients is necessary.

Taking a history of the presenting symptoms is an essential step for diagnosis. In case the patient is unable to give a reliable history due to the condition, history can be taken from witnesses or family members. Understanding the onset of the symptom allows one to decide on the management steps. The pace at which the symptoms develop is another important part of the history taking as the gradual presentation of symptoms might be an indication of alternative diagnoses. Furthermore, the background of the patient needs to be assessed to identify risk factors that might lead to stroke.

Conducting a vital signs check, and a physical examination with a focus on neurological examination is required to be done at every suspected stroke case. Almost 80% of patients with an acute ischaemic stroke present with high blood pressure (≥140 mmHg systolic). This sudden elevation improves over the following week, and the cause of it is as yet unknown.³

Rapid assessment of the brain using imaging techniques is a crucial step in stroke diagnosis. Brain scans help to determine the cause (ischaemic or haemorrhagic), the location, and the severity of a stroke. CT and MRI scans are the main imaging techniques for the diagnosis of stroke. 

Although CT scans are quick and effective in terms of determining the cause along with deciding on the treatment, it is not as effective as MRI scans for ischaemia, especially for a minor stroke.³ A special dye called contrast might be used during a CT scan as well as an MRI scan.

Management and treatment for an ischaemic stroke

An ischaemic stroke is a medical emergency that needs to be recognised without delay. Early recognition and appropriate treatment enable a reduction of death and long-term disabilities. The phrase “time is brain” is used to emphasise the importance of early delivery of treatment. A multidisciplinary team of healthcare professionals is involved in the management of ischaemic stroke.⁴

Ischaemic stroke management aims to save viable brain tissue by regaining blood flow to the area. This type of treatment is called reperfusion therapy. Intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT) are two reperfusion options available. 

Intravenous thrombolysis is a type of treatment in which a medicine called alteplase is injected into the body to dissolve the blood clot. It is proven to be effective when administered up to 4.5 hours from the onset of symptoms. Patients presenting at 4.5-6 hours of symptom onset might also benefit from IVT and should be considered on an individual basis. As with any other treatment, IVT has side effects, bleeding being the most feared. Therefore, there is currently little evidence to support its use in patients with non-disabling ischaemic stroke.³

Endovascular thrombectomy is used for strokes affecting large vessels and is a type of procedure which involves the removal of the blood clot by inserting a catheter into the body through a vessel. The effectiveness of EVT is dependent on time from the symptom onset, as with IVT. However, there is evidence showing its benefit beyond 6 hours.³

Acute stroke units provide multidisciplinary care and function to monitor stroke patients to prevent any short-term problems by providing supportive treatments. Therefore, it is recommended that all ischaemic stroke patients should be admitted to an acute stroke unit.³

Certain medications to prevent future clots or reduce other risk factors contributing to clot formation may also be offered for stroke patients. These include aspirin, antiplatelets, anticoagulants, blood pressure-lowering medicines, and lipid-lowering medicines called statins.

Risk factors

There are many risk factors for suffering from a stroke. Risk factors for ischaemic stroke include:⁵

• High blood pressure
• Diabetes
• Heart and blood vessel diseases
• High cholesterol levels (LDL)
• Smoking
• Viral infections or conditions that cause inflammation
• Age
• Sex
• Race
• Family and genetic history
• High stress levels, anxiety, depression
• Living or working in areas with air pollution
• Unhealthy lifestyle habits, including unhealthy diet, sedentary lifestyle, drinking alcohol, getting more than 9 hours of sleep
• Certain medications
• Using illegal drugs such as cocaine
• Being overweight or obese

Due to having a longer life expectancy, the lifetime risk of having a stroke is higher in people assigned female at birth (AFAB). Certain risk factors increasing stroke risk in people with AFAB are birth control pills, hormone replacement therapy, and pregnancy. 

Risk factors for younger adults are more diverse and include less common risk factors such as inflammatory or familial conditions, genetic factors, defects present from birth, migraine with aura, and malignancies.⁵ However, according to recent studies, an unignorable increase in the stroke rate in younger adults (under 50 years old) has been linked to an increased prevalence of traditional risk factors such as high cholesterol levels, high blood pressure, and diabetes.⁶ 

The SARS-CoV2 virus, the cause of the Covid-19 pandemic, is another risk factor for ischaemic stroke. The mechanism of ischaemia is related to immune mechanisms and increased clot formation.⁷

Complications

The damage to the brain caused by a stroke may result in temporary or permanent problems depending on the severity and location of the injury. Some of the complications of stroke include:

• Psychological problems such as depression and anxiety
• Problems in cognition, such as communication, memory, concentration, and ability to perform skilled physical activities
• Movement problems such as weakness, paralysis or balance problems
• Fatigue 
• Problems with communication, such as speaking, understanding, reading, and writing
• Problems with swallowing known as dysphagia
• Problems with vision
• Problems with controlling bladder or bowel
• Problems with erection

There are also some short-term complications of a stroke, including infections, constipation, clot formation in the legs or the lungs, and falls.

Complications following a stroke can be short-term for some people. However, some may experience problems for a longer time and need support. Stroke rehabilitation programmes help improve the ability to cope with activities of everyday life; building lost skills and independence after a stroke. Stroke rehabilitation programmes are designed on an individual basis consisting of different therapies. 

FAQs

How can I prevent an ischaemic stroke?

A stroke, along with its complications, is one of the most common causes of disability and death worldwide. Therefore, identifying and addressing the stroke risk factors and the underlying cause is crucial for the prevention of ischaemic stroke.⁸ 

Having a stroke or TIA increases the risk of having another stroke. Therefore, long-term treatment with certain medications can be necessary to prevent future strokes. These may include medications for high blood pressure, medications to prevent clot formation called anticoagulants or antiplatelets, and medications to decrease high cholesterol levels called statins.

Atrial fibrillation (AF) is a condition of the heart characterised by an irregular heartbeat and is a well-established risk factor for ischaemic stroke. AF causes a tendency for clot formation, which can then detach a piece of clot called emboli that travels to the brain, causing a blockage and, thus, stroke. Anticoagulants are used to prevent ischaemic stroke caused by AF.⁸ 

The best way to prevent future strokes is to adopt a healthy lifestyle by eating healthily, exercising regularly, reducing alcohol consumption, and not smoking.

How common is an ischaemic stroke?

According to the World Stroke Organisation’s Global Stroke Fact Sheet, strokes are the second-leading cause of death and the third-leading cause of death and disability combined. 

Statistics show that there are over 12.2 million new stroke cases per year worldwide, and 101 million people are living with long-term effects of a stroke. In addition, one in four people over the age of 25 are expected to have a stroke in their lifetime. This number has increased by 50% over the last 17 years. The number of people living with stroke aftermath, on the other hand, has almost doubled over the last 30 years. 

Ischaemic stroke is the most common cause of stroke, with over 7.6 million new cases happening each year. That is over 62% of all stroke cases worldwide. Out of 101 million people living with stroke aftermath, 77 million are due to ischaemic stroke. Finally, around 3.3 million people lost their lives as a result of ischaemic stroke.⁹ 

Who is at risk of an ischaemic stroke?

A stroke may occur at any age. Babies under the age of 1 and older adults are at higher risk.⁵ However, the 2019 Global Burden of Disease showed that 63% of all stroke cases and 58% of all ischaemic stroke cases occur in people under age 70. These statistics are an indication of the fact that strokes are no longer considered a disease of the elderly.

Among all ischaemic stroke cases, 45% occurred in people assigned male at birth (AMAB); whereas 55% occurred in people assigned female at birth (AFAB).⁹ Nevertheless, people with AMAB have a higher risk of getting a stroke at younger ages compared with people with AFAB.⁵ 

People with high blood pressure are significantly at risk of having a stroke due to high systolic blood pressure being a leading risk factor. Other risk factors that put you at risk of having a stroke include poor diet, high body mass index, high fasting blood sugar, exposure to air pollution, smoking, high cholesterol, kidney disease, drinking alcohol, and low physical activity.⁹ 

What can I expect if I have an ischaemic stroke?

Ischaemic stroke symptoms and severity differ from person to person depending on the location and extent of the brain damage. You might experience acute onset of symptoms that may disappear within 24 hours in the case of a transient ischaemic attack. 

At the hospital, you will undergo a full assessment, including a neurological examination and might need a scan for diagnosis. Stroke treatment depends on the stroke type, location, and the underlying cause and clinical presentation, as well as the duration since the start of the symptoms. You might be given medicine to dissolve blood clots or need a procedure to recanalise the blocked vessel. If you are medically unstable, you might also be given appropriate treatment to stabilise the vital signs. 

The aftermath of ischaemic stroke also varies between individuals depending on the severity of the brain damage. Some people may experience mild symptoms and recover completely; however, others may face more significant challenges and require long-term rehabilitation.

When should I see a doctor?

If you or someone else around you has signs or symptoms of stroke, it is time to call 999 immediately. Even if the symptoms disappear before the help arrives, it is still essential to get an immediate assessment at the hospital. Therefore, it is very important to be able to recognise the possible signs and symptoms of stroke, which can be remembered with the mnemonic FAST. 

It is also very important to manage any risk factors and conditions effectively to prevent future strokes. You can get an effective management plan by seeing a doctor. Attending regular follow-ups, complying with prescribed medications, and following lifestyle advice can significantly reduce your stroke risk.

Summary

An ischaemic stroke is an emergency condition caused by a disrupted blood flow to brain tissue. Depending on the extent of the brain damage, a stroke may result in death or long-term disabilities. The main symptoms of ischaemic stroke involve weakness and numbness of the face or the limbs, along with slurred speech. It is crucial to recognise the possible stroke signs and symptoms and seek immediate help from a healthcare provider without any delay.

Neurological examination and brain scans help in the diagnosis of ischaemic stroke. Treatment aims to maintain the blood flow by recanalisation with medication to dissolve clots or a procedure to remove clots. Long-term problems caused by ischaemic stroke can be managed with a stroke rehabilitation programme.

The most important risk factors for ischaemic stroke include high blood pressure, high cholesterol levels, high body mass index, high blood sugar, poor diet, low physical activity, smoking, and drinking alcohol. It is very important to manage risk factors to decrease future stroke risk by attending regular follow-ups, taking your medications as prescribed, and adopting a healthy lifestyle.