Ischemic Stroke (Stroke)

What is Ischemic Stroke (Stroke)?

An acute stroke refers to the sudden start of specific neurological issues due to diseases that affect the vessels that supply blood to the brain, retina or spinal cord. Strokes are common among various patient groups and can lead to severe health problems and even death. There are two main types of strokes: ischemic and hemorrhagic. Hemorrhagic strokes can be further divided into intracerebral and subarachnoid stroke. After that, ischemic strokes fall into a few different categories based on the TOAST classification, which includes: cardioembolism, small vessel occlusion, large artery atherosclerosis, undefined cause of stroke, and other specific causes of stroke.

This classification is necessary because it enables the doctor to determine the subtype of stroke as either “probable” or “possible”. A “probable” diagnosis means that the patient’s symptoms, brain imaging results, and diagnostic tests all point to a certain subtype of stroke, and no other potential causes are found. A “possible” diagnosis is given if the symptoms and brain scans hint at a specific subtype, but more tests are needed. Given that many patients can only undergo a limited amount of tests, these “probable” and “possible” labels help physicians to make the most accurate diagnosis possible.

What Causes Ischemic Stroke (Stroke)?

Ischemic stroke is caused by a blockage or clot that disrupts the blood flow to the brain. This can occur in two main ways: a thrombotic event, where the clot forms directly in the blood vessel (often because of conditions like hardening arteries, arterial tearing, growth of muscle tissue in the artery walls, or inflammation), and an embolic event, when debris from elsewhere in the body ends up blocking the blood flow. The debris might come from an atherosclerotic plaque in the carotid artery or even the heart. Sometimes, the debris can even come from the right side of the circulatory system through a small hole in the heart, known as a patent foramen ovale.

Different types of strokes can offer clues about their causes, which in turn can impact a patient’s prognosis and treatment.

People who have had a cardioembolic stroke usually have a blockage connected to a problem in the heart. Heart problems that can cause these blockages are ranked by their potential risk, from high to medium. If at least one cardiac source of a clot is identified, a stroke might be cited as cardioembolic. If a large artery in the brain with atherosclerotic changes does not seem to be the cause, doctors might consider this a possible cardioembolic stroke.

When someone is suffering from a large artery atherosclerosis stroke, their clinical and brain scanning findings would show a significant (50% or more) narrowing or complete blocking of a major brain artery. This blockage is usually because of atherosclerosis, a condition where plaque builds up inside the arteries. Symptoms can include issues like language difficulties, ignoring one side of the world, or decreased motor functions, and even issues related to the lower part of the brain and balance control center, the cerebellum. If your brain scans show signs that match these conditions and the examining physician can rule out it being from a heart-related clot, then your stroke may be attributed to large artery atherosclerosis.

In cases of small vessel occlusion, these types of strokes are often referred to as ‘lacunar infarcts.’ Typically, patients with this type of stroke present clinical symptoms that match this pattern and do not show signs of any brain problems. Additionally, their brain scans should be normal or should show a relevant lesion smaller than 1.5 cm. People with this type of stroke often have diabetes or high blood pressure.

In some cases, determining the cause of a stroke can be challenging. Sometimes multiple potential causes make it hard to diagnose or an extensive evaluation may still lead to an unknown cause. Other times, only a basic evaluation is performed, leaving cause undetermined. A patient with a medium-risk heart-related clot source along with another potential cause, or a patient with a heart rhythm problem and a neck carotid artery blockage of 50%, might fall into this category.

Last but not least, the group that falls under strokes of other determined causes comprises patients with uncommon causes like blood vessel conditions which aren’t related to the build-up of fatty substances, having an easily clotting blood condition, or blood disorders. Regardless of the size or location of the lesion, these patients should show clinical symptoms and brain scan findings that are signs of ischemic stroke. Other tests like bloods or arteriography should reveal one of these unusual causes, and additional screenings should rule out heart-derived clots or large artery atherosclerosis.

Risk Factors and Frequency for Ischemic Stroke (Stroke)

In 2021, strokes were a major cause of death from heart disease, with a person in the US suffering a stroke every 40 seconds. This means that a death related to stroke occurred every 3 minutes and 14 seconds. Each year, over 795,000 Americans have a stroke, and for around 610,000 of them, it’s their first one. About a quarter of these strokes happen in people who have already had a stroke before. The most common type of stroke is an ischemic stroke, which happens when blood flow to the brain is blocked, making up 87% of all strokes.

The cost of stroke in the US reached nearly $56.5 billion between 2018 and 2019. This includes the cost of healthcare, medicine, and lost productivity from missing work. Stroke is a main cause of severe, long-term disability, particularly impacting the mobility of more than half of stroke survivors aged 65 and older.

• Strokes resulted in 1 in 6 cardiovascular deaths in 2021, with a person experiencing a stroke every 40 seconds.
• More than 795,000 Americans have a stroke annually – of these 610,000 are first occurrences.
• About 185,000 strokes occur in those who have previously had a stroke.
• Ischemic strokes, which block blood flow to the brain, make up 87% of all strokes.
• The financial burden of strokes in the US between 2018 and 2019 was nearly $56.5 billion, including healthcare expenses, medication, and work absenteeism.
• Strokes significantly contribute to severe long-term disabilities, particularly affecting mobility in over half of stroke survivors aged 65 and up.

There are significant differences in stroke rates and outcomes among different racial and ethnic groups. Non-Hispanic Black adults are almost twice as likely to have a first stroke compared to White adults. Both non-Hispanic Black and Pacific Islander adults have the highest rates of death from stroke. The stroke-related death rate increased from 38.8 per 100,000 in 2020 to 41.1 per 100,000 in 2021.

Signs and Symptoms of Ischemic Stroke (Stroke)

Ischemic strokes happen suddenly. It’s very important to figure out when the symptoms first started. If we’re not sure when the symptoms began, the last time the patient felt normal and didn’t have any new neurological symptoms is used as a reference point. This helps doctors decide whether it’s appropriate to use intravenous (IV) thrombolytics – a type of medication. Identifying any possible underlying causes is also essential. These can include things like high blood pressure, a history of stroke or TIAs, smoking, diabetes, cardiac diseases, neck injuries, recent chiropractic manipulations, and signs of blood clotting.

Patients suspected of having a stroke should always have a neurological examination. This includes checking their vital signs and heart rhythms, and listening for any unusual sounds in the neck that could indicate problems with blood flow. A standard tool called the National Institutes of Health Stroke Scale (NIHSS) is often used to assess how severe a stroke is. This tool tests 11 different aspects of neurological function, and each is given a score from 0 to 42.

Testing for Ischemic Stroke (Stroke)

For treating a sudden stroke, a clear, quick plan is crucial. It’s advised that stroke treatment should start within 60 minutes of arriving at the hospital. This early start is critical for patients suffering from a stroke caused by a blood clot, who may benefit from medication or procedures that break up the clot.

Immediate goals of stroke treatment should focus on:

• Maintaining overall health, especially focusing on airways, breathing, and blood circulation.
• Rapidly fixing any conditions that could be worsening the patient’s stroke symptoms.
• Evaluating if the patient could benefit from clot-busting medicine or a procedure to remove the clot.
• Trying to understand the root cause of the patient’s stroke symptoms.

Initial assessments should cover airway, breathing, circulation, and vital signs, as some patients may have trouble breathing due to high pressure within the brain, and might be at risk of choking. They might need a tube placed down their throat to help them breathe.

A quick fingertip glucose check should be done because low blood sugar can sometimes cause symptoms that mimic a stroke.

A CT scan of the head should be done within 20 minutes of arrival to the hospital to check for bleeding within the brain. Advanced imaging might be considered if the hospital has the capacity to offer emergency treatments like removing clots from blood vessels in the brain. Nonetheless, these treatments shouldn’t delay the administration of clot-busting drugs.

One specific type of MRI, known as diffusion-weighted imaging (DWI), can detect a stroke caused by a clot in a short time because it can identify changes in the brain tissue due to the blockage. It provides results much more quickly than other MRI types, like FLAIR, and can help doctors decide whether clot-busting therapy can still be used.

Other important tests include an ECG to monitor the heart’s health, measures of a heart muscle protein called troponin, a complete blood count, electrolytes, kidney function tests, and clotting factors. These tests can provide more information about possible risk factors and complications related to the stroke.

If the hospital doesn’t have a radiology expert to check the imaging studies promptly, a system to allow remote viewing and interpretation of these studies is strongly recommended. This can help make decisions about using clot-dissolving drugs. Similarly, consulting with stroke and radiology experts remotely may be useful in places without a stroke team or a coordinated stroke treatment process. However, the evidence to support these recommendations is limited.

Treatment Options for Ischemic Stroke (Stroke)

The aim of treating an acute ischemic stroke is to preserve the parts of the brain where blood flow is reduced but hasn’t entirely stopped, preventing them from dying. We achieve this by restoring the blood flow, and using methods such as IV (intravenous) recombinant tissue-type plasminogen activator or mechanical thrombectomy. Restoring blood flow must be done quickly to minimize the impact of reduced blood flow (ischemia). Some doctors use endovascular techniques to treat acute ischemic strokes. There are also neuroprotective medications, but none have proven to improve the outcome.

Here are some treatments proven to be effective:

1. Acute Reperfusion Therapy: This approach restores blood flow and incorporates medicines such as IV alteplase and IV tenecteplase, given within 4.5 hours of a stroke starting. These are recommended by groups like the American Heart Association (AHA) for patients fitting certain criteria.

2. Mechanical thrombectomy: This is a procedure that removes the blood clot causing the stroke. It can be used within 6 hours of the stroke beginning. You can even use it in combination with other treatments such as perfusion studies, extending the time frame up to 24 hours for selected patients.

3. Managing blood pressure: It’s crucial to keep your blood pressure under control. Guidelines recommend a target of less than 180/105 mm Hg for the first 24 hours after taking IV alteplase.

4. Nutrition and DVT prophylaxis: Early feeding via tubes may reduce the risk of death. Using compression to prevent blood clots in the legs is also a standard preventive treatment for immobile patients.

5. Seizures: Not all patients will experience seizures after a stroke. If they do, the best course of action is usually short-term antiepileptic drug treatment.

6. Cardiovascular assessment: Once in hospital, patients will be monitored for heart issues for the first 24 hours.

7. Other treatments: These include aspirin, which is recommended within 24 to 48 hours of symptom onset to prevent recurrent stroke, while full-dose anticoagulation is generally not recommended in the acute phase. Blood thinners for those with atrial fibrillation might usually be started 7-14 days after stroke symptoms appear.

In all cases, early recognition, appropriate intervention, and ongoing management are vital to minimize the impact of the stroke and improve long-term recovery.

What else can Ischemic Stroke (Stroke) be?

When a doctor is trying to determine if a patient has had an ischemic stroke, they have to consider several other conditions that can cause similar symptoms. These conditions include:

• Complex migraines
• Side effects from certain drugs
• Brain abscesses
• Bleeding within the brain
• Brain tumors
• High blood sugar (hyperglycemia)
• Low blood sugar (hypoglycemia)
• Brain damage from high blood pressure
• Abnormalities in the body’s metabolism
• Movement disorders
• Multiple sclerosis
• Seizures
• Blood poisoning or sepsis
• Fainting (syncope)
• Wernicke’s encephalopathy, a serious brain disorder due to thiamine deficiency

The doctor has to consider all of these conditions and rule them out based on the results of various tests to confirm a diagnosis of ischemic stroke.

What to expect with Ischemic Stroke (Stroke)

The prognosis, or expected outcome, for stroke patients is crucial for determining treatments and informing patients and their caregivers about what to expect. This includes looking at various factors such as the type and severity of the stroke, any existing neurological problems, other health conditions, and how well the person responds to treatment.

Doctors use different tools, like clinical scales and imaging methods, to help predict things like how well the person may be able to function, the chance of death, and the risk of having another stroke. Early treatment and rehabilitation can greatly improve the prognosis, which shows how important it is to get medical help quickly and have care tailored to the individual’s needs.

While some individuals may fully recover from a stroke, others might have long-term disabilities or complications. Therefore, the management of stroke patients often requires a team of healthcare professionals, continuous monitoring, and support. This approach aims to ensure the best possible results and improve the quality of life for those affected and their families.

Possible Complications When Diagnosed with Ischemic Stroke (Stroke)

An acute ischemic stroke can lead to several complications. These problems can vary, but often include:

• Deep vein thrombosis (DVT) and pulmonary embolism: a form of clot prevention is necessary.
• Aspiration and pneumonia: it’s always important to assess a person’s ability to swallow before feeding, which is a standard procedure in stroke centers.
• Seizures
• Depression
• Cerebral edema (swelling in the brain) and increased pressure inside the skull

Recovery from Ischemic Stroke (Stroke)

Starting rehabilitation soon after a stroke can be helpful for patients. However, it’s not recommended to begin rehabilitation within the first 24 hours. In the AVERT trial, patients were randomly assigned to start very early rehabilitation – within 24 hours of having a stroke – or to receive the usual care given in a stroke unit. The results showed that patients who were mobilized early didn’t do as well on a performance assessment known as the modified Rankin score.

Preventing Ischemic Stroke (Stroke)

Ways to prevent strokes, particularly ischemic strokes, have a huge role in lowering the amount of strokes that occur and lessening their impact. This can be done by managing changeable risk factors such as high blood pressure, diabetes, high cholesterol levels, and smoking. This can be achieved by changing your lifestyle and taking specific medications. By doing this, you can greatly lower your chances of having a stroke.

It’s also crucial to know the early signs of a stroke and get medical help as soon as possible if you have signs like sudden weakness, being numb, or having trouble speaking. Quick treatment can help to lessen the damage. Teaching communities about living healthier, like regular exercise and a healthy diet, also adds to efforts to prevent strokes.

Put simply, by focusing on both individual habits and wider societal elements, we can lessen the impact of strokes and improve public health overall.