Understanding Strokes In The 1970S: A Historical Perspective

In the 1970s, the World Health Organization (WHO) defined a stroke as a neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours. This definition was intended to reflect the reversibility of tissue damage and was devised to distinguish between a stroke and a transient ischemic attack (TIA), or mini-stroke.

A stroke, sometimes referred to as a cerebrovascular accident (CVA) or brain attack, occurs when there is an interruption in the blood supply to the brain, resulting in brain cell death. This can be due to a lack of blood flow, known as an ischemic stroke, or bleeding in the brain, known as a hemorrhagic stroke.

Strokes are life-threatening medical emergencies that require immediate attention to prevent permanent damage or death. The faster a person having a stroke receives medical care, the more likely it is that the effects of the stroke will be limited or reversible.

The World Health Organization's definition of 'stroke'

In the 1970s, the World Health Organization (WHO) defined "stroke" as a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours". This definition was intended to reflect the reversibility of tissue damage and was devised for this purpose, with the 24-hour time frame being chosen arbitrarily. The 24-hour limit differentiates stroke from transient ischemic attack (TIA), a related syndrome of stroke symptoms that resolve completely within 24 hours.

The WHO's definition of stroke has evolved and been refined over time as medical understanding of the condition has advanced. Today, the organization recognizes two primary types of stroke: ischemic and hemorrhagic. An ischemic stroke occurs when a blood clot blocks a blood vessel in the brain, cutting off blood flow. Hemorrhagic stroke, on the other hand, happens when a blood vessel in the brain breaks open, causing bleeding and accumulation of blood.

The WHO's definition and classification of stroke are essential for medical professionals to accurately diagnose, treat, and manage this life-threatening condition. The organization's guidelines play a crucial role in shaping global health policies and practices related to stroke prevention, treatment, and rehabilitation.

Stroke is a leading cause of death and disability worldwide. According to the WHO, about 15 million people worldwide suffered a stroke in 2023. The organization's efforts to raise awareness, promote prevention, and improve treatment have contributed to a decrease in stroke incidence in developed countries while also helping to reduce the impact of stroke on individuals and communities.

The two types of stroke: ischemic and hemorrhagic

In the 1970s, the World Health Organization defined a stroke as a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours".

Today, we know that there are two main types of stroke: ischemic and hemorrhagic.

Ischemic Stroke

Ischemic strokes are the most common type, accounting for about 80-87% of all strokes. They occur when blood flow to the brain is blocked, usually by a blood clot. This blockage causes brain cells to be deprived of oxygen, leading to cell death and brain damage. Ischemic strokes typically happen in one of the following ways:

• Formation of a clot in the brain (thrombosis)
• A fragment of a clot that formed elsewhere in the body breaks free and travels to the brain (embolism)
• Small vessel blockage (lacunar stroke) due to long-term untreated high blood pressure, high cholesterol, or high blood sugar
• Unknown reasons (cryptogenic strokes)

Hemorrhagic Stroke

Hemorrhagic strokes, on the other hand, are caused by bleeding in or around the brain. This happens when a weakened blood vessel ruptures, often due to uncontrolled high blood pressure. There are two types of hemorrhagic strokes:

• Intracerebral hemorrhage: bleeding inside the brain due to a ruptured blood vessel
• Subarachnoid hemorrhage: bleeding between the brain and its outer covering, which puts pressure on the underlying brain tissue

Both types of strokes are medical emergencies that require immediate attention. Treatment options vary depending on the type of stroke and the time since the onset of symptoms. For ischemic strokes, the priority is to restore circulation, while for hemorrhagic strokes, reducing blood pressure and stopping the bleeding are crucial.

The symptoms of a stroke

In the 1970s, the World Health Organization defined "stroke" as a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours".

A stroke is a medical emergency that occurs when there is an issue with blood flow to the brain. This can be due to blocked arteries or bleeding in the brain, resulting in brain cells dying from a lack of oxygen. It is critical to seek immediate medical attention to prevent permanent damage or death.

To recognize the warning signs of a stroke, the American Stroke Association recommends using the acronym F.A.S.T:

• F: Face Drooping – Does one side of the face droop or is it numb? Ask the person to smile and check if their smile is uneven.
• A: Arm Weakness – Is one arm weak or numb? Ask the person to raise both arms and observe if one arm drifts downward.
• S: Speech Difficulty – Is the person's speech slurred or strange? Are they having trouble choosing the right words?
• T: Time to call 911 – Every minute counts in a stroke. Call emergency services immediately and note the time when the symptoms first appeared.

In addition to F.A.S.T, there are other symptoms that may indicate a stroke:

• Sudden numbness or weakness in the face, arm, or leg, especially on one side of the body.
• Sudden confusion, trouble speaking, or difficulty understanding speech.
• Sudden loss of vision in one or both eyes, or double vision.
• Sudden dizziness, loss of balance, or lack of coordination.
• Sudden severe headache with no known cause.
• Nausea and vomiting.
• Emotional instability and personality changes.
• Memory loss.
• Passing out or fainting.

It is important to note that a transient ischemic attack (TIA) or "mini-stroke" can also occur, with similar symptoms that last only a few minutes to 24 hours. A TIA is a warning sign of a potential stroke in the future, and it is crucial to seek medical attention even if the symptoms go away.

The causes of a stroke

In the 1970s, the World Health Organization defined a stroke as a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours".

Today, a stroke is defined as a medical emergency that occurs when there is an issue with blood flow to the brain. This can be due to blocked blood vessels or bleeding in the brain. There are two main types of stroke: ischemic and hemorrhagic.

Ischemic strokes are the most common, accounting for about 80% of all strokes. They occur when blood vessels in the brain are blocked, usually by a blood clot, cutting off blood flow. Ischemic strokes usually happen in the following ways:

• Formation of a clot in the brain (thrombosis)
• A fragment of a clot that formed elsewhere in the body breaks free and travels through the blood vessels until it gets stuck in the brain (embolism)
• Small vessel blockage (lacunar stroke), which can be caused by long-term untreated high blood pressure, high cholesterol, or high blood sugar
• Unknown reasons (cryptogenic strokes)

Hemorrhagic strokes cause bleeding in or around the brain and happen in two ways:

• Bleeding inside the brain (intracerebral), which occurs when a blood vessel tears or breaks open
• Bleeding into the subarachnoid space, which is the area between the brain and its outer covering

Several factors can increase the risk of stroke, including high blood pressure, high cholesterol, Type 2 diabetes, atrial fibrillation, alcohol use disorder, migraine headaches, smoking, and drug misuse. Stroke is a leading cause of death and disability worldwide.

The treatment of a stroke

For ischemic strokes, caused by a blockage in an artery supplying blood to the brain, the primary treatment option is thrombolysis, or clot-busting therapy. This involves administering a medication called a tissue plasminogen activator (tPA) to dissolve the clot and restore blood flow to the affected area of the brain. This treatment is most effective when given within 4.5 hours of stroke symptoms appearing, and patients may receive it either in a hospital or via a mobile stroke unit, which can provide treatment en route to the hospital.

Mechanical thrombectomy is another treatment option for ischemic strokes, particularly for large clots or those that cannot be treated with tPA alone. This procedure involves inserting a small catheter into an artery in the groin and guiding it through the blood vessels to the site of the blockage in the brain. A device is then used to grab and remove the clot, restoring blood flow. This treatment can be effective up to 24 hours after stroke symptoms begin, but like thrombolysis, it is most beneficial when performed as soon as possible.

For hemorrhagic strokes, caused by a burst blood vessel in the brain, the treatment approach is different. The primary goal is to stop the bleeding and reduce pressure on the brain. Surgery may be required to repair the damaged blood vessel and remove any blood clots that have formed. Patients may also be given medications to lower their blood pressure and prevent further bleeding. In some cases, doctors may also recommend endovascular coiling, a procedure where a small coil is inserted into the affected blood vessel to block it off and prevent further bleeding.

Following the initial treatment for a stroke, patients often require rehabilitation to help them recover and adapt to any lasting effects of the stroke. This may include physical therapy to improve movement and strength, speech therapy to address any language or communication issues, and occupational therapy to help the person regain independence in daily tasks. Rehabilitation can often be a long-term process, and ongoing support is crucial to help individuals regain their quality of life.

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