Stroke

A stroke is a life-threatening medical condition that occurs when the blood supply to a part of the brain is interrupted or reduced. This disruption prevents brain tissue from receiving essential oxygen and nutrients, leading to the death of brain cells within minutes. Acute strokes are a leading cause of death and disability worldwide, yet they are often preventable with proper education, lifestyle changes, and timely medical intervention.

What is a Stroke?

Stroke, often referred to as a "brain attack," is an emergency that requires immediate medical attention. Strokes happen when blood flow to a part of the brain is interrupted by a blockage or a rupture in a blood vessel. Without the necessary blood flow, the brain is deprived of oxygen and glucose, leading to the death of brain cells and potential loss of function in the affected area.

The brain controls various bodily functions like movement, speech, memory, and sensation. When a stroke affects one area of the brain, it can result in loss of function in the corresponding body part. Depending on the severity of the stroke, the consequences can range from temporary weakness to permanent paralysis or even death.

Types of Stroke

There are three primary types of stroke:

• Ischemic Stroke
• Hemorrhagic Stroke
• Transient Ischemic Attack (TIA)

Each type has different causes but shares common risk factors and symptoms.

1. Ischemic Stroke

An ischemic stroke occurs when a blood clot blocks or narrows an artery supplying blood to the brain. This type of stroke accounts for about 85% of all strokes. Ischemic strokes are further divided into two categories:

• Thrombotic Stroke: This occurs when a blood clot (thrombus) forms in one of the arteries that supply blood to the brain. The clot typically forms in an area affected by atherosclerosis, the buildup of fatty deposits on the artery walls.
• Embolic Stroke: An embolic stroke occurs when a blood clot or other debris forms in another part of the body—usually the heart—and is swept through the bloodstream to the brain. Once it reaches the brain, the clot lodges in a narrower artery, blocking blood flow.

2. Hemorrhagic Stroke

A hemorrhagic stroke may occur when a weakened blood vessel in the brain ruptures and spills blood into or around the brain. This extra blood puts pressure on brain cells and damages them. Hemorrhagic strokes can be caused by conditions like high blood pressure, aneurysms (weakened spots in blood vessel walls), and arteriovenous malformations (AVMs), which are abnormal tangles of blood vessels.

Hemorrhagic strokes are classified into two types:

• Intracerebral Hemorrhage: This occurs when an artery in the brain bursts, flooding the surrounding tissue with blood.
• Subarachnoid Hemorrhage: This occurs when bleeding happens in the area between the brain and the thin tissues that cover it, known as the subarachnoid space. The rupture of an aneurysm often causes subarachnoid haemorrhages.

3. Transient Ischemic Attack (TIA)

A Transient Ischemic Attack (TIA), often called a "mini-stroke," occurs when blood flow to the brain is temporarily disrupted, causing stroke-like symptoms. TIAs last only a few minutes to a few hours and do not cause permanent damage. However, they are a severe warning sign of a future stroke, as 1 in 3 people who experience a TIA will have a full-blown stroke in the future.

Symptoms of Stroke

Recognising the symptoms of a stroke quickly can save lives. The acronym F.A.S.T. is a helpful way to remember the most common stroke symptoms and what to do if someone is having a stroke:

• F – Face Drooping: Does one side of the face droop, or is it numb? Ask the person to smile to see if their smile is uneven.
• A – Arm Weakness: Is one arm weak or numb? Ask the person to raise both arms. Does one arm drift downward?
• S – Speech Difficulty: Is speech slurred or hard to understand? Can the person repeat simple sentences like "The sky is blue"?
• T – Time to Call for Help: If someone shows any of these symptoms, even if the symptoms go away, call emergency services immediately. Time is crucial when dealing with a stroke.

Other signs of a stroke can include one or more of the following:

• Sudden confusion or trouble understanding speech
• Sudden numbness or weakness in the face, arm, or leg, particularly on one side of the body
• Sudden trouble seeing in one or both eyes
• Sudden difficulty walking, dizziness, loss of balance or coordination
• Sudden severe headache with no known cause

Risk Factors for Stroke

Several factors can increase your risk of stroke, some of which can be controlled or treated, while others cannot. Risk factors are generally divided into modifiable and non-modifiable categories.

Modifiable Risk Factors

• High Blood Pressure (Hypertension): High blood pressure is the leading cause of stroke. It damages blood vessels over time, making them more likely to rupture or become blocked.
• Smoking: Smoking increases the risk of stroke by damaging blood vessels, raising blood pressure, and increasing the likelihood of clot formation.
• High Cholesterol: Elevated cholesterol levels in the blood can lead to atherosclerosis, where plaques form in the arteries, increasing the risk of ischemic stroke.
• Diabetes: Diabetes increases the risk of stroke by contributing to the buildup of fatty deposits in the arteries and raising blood pressure.
• Obesity: Excess body weight contributes to other stroke risk factors, such as high blood pressure, diabetes, and high cholesterol.
• Physical Inactivity: A sedentary lifestyle is associated with higher risks of cardiovascular diseases, including stroke.
• Poor Diet: A diet high in saturated fats, trans fats, and cholesterol can increase stroke risk. Similarly, excessive salt intake contributes to high blood pressure.
• Excessive Alcohol Consumption: Drinking too much alcohol raises blood pressure and contributes to obesity, heart disease, and stroke.

Non-Modifiable Risk Factors

• Age: The risk of stroke increases as you get older. After age 55, your stroke risk doubles every decade.
• Family History: If a close relative has had a stroke, you may be at increased risk due to shared genetic factors and lifestyle patterns.
• Gender: While both men and women can have strokes, women are more likely to die from them. Women also have unique risk factors, such as pregnancy and hormone replacement therapy.
• Previous Stroke or TIA: If you've had a stroke or TIA in the past, you're at higher risk of having another.

Diagnosis of Stroke

If a stroke is suspected, getting to the hospital immediately is essential. Doctors will perform various tests to diagnose the stroke, determine its type, and assess the extent of brain damage. Common diagnostic tools include:

• Physical Examination: A thorough neurological exam will assess motor function, coordination, speech, and cognitive abilities.
• Imaging Tests:
  • CT Scan: A computed tomography (CT) scan of the brain is often the first test performed. It helps doctors identify if the stroke is ischemic or hemorrhagic.
  • MRI Scan: Magnetic resonance imaging (MRI) provides detailed brain images and can detect more minor strokes that might not appear on a CT scan.
• Blood Tests: Blood tests can provide information about blood clotting, glucose levels, and infection, which are essential factors in stroke diagnosis.
• Carotid Ultrasound: This test uses sound waves to produce images of the carotid arteries in the neck. It helps detect plaque buildup or narrowing of these arteries, which supply blood to the brain.
• Cerebral Angiogram: A dye is injected into blood vessels to visualise them on X-rays. This test helps detect blood vessel abnormalities, such as aneurysms or arteriovenous malformations.
• Echocardiogram: This test uses sound waves to create images of the heart and can help detect sources of blood clots that may have travelled to the brain.

Treatment of Stroke

Immediate stroke treatment depends on the type of stroke—ischemic or hemorrhagic—and aims to restore blood flow to the brain or control the bleeding.

1. Treatment for Ischemic Stroke

Since blocked arteries cause ischemic strokes, treatment focuses on restoring blood flow as quickly as possible.

• Clot-Busting Medications: Tissue plasminogen activator (tPA) is a clot-busting drug that dissolves clots and restores blood flow. It must be administered within a few hours of symptom onset to be effective.
• Endovascular Procedures: In some cases, doctors may perform a thrombectomy, a minimally invasive procedure that involves using a catheter to remove the clot from the blocked artery.
• Aspirin: If a patient arrives at the hospital within 48 hours of an ischemic stroke, aspirin may be given to reduce the risk of further clot formation.

2. Treatment for Hemorrhagic Stroke

For hemorrhagic strokes, treatment focuses on controlling bleeding and reducing pressure on the brain.

• Surgical Procedures: If a large haemorrhage is present, surgery may be needed to remove the blood and relieve pressure on the brain.
• Aneurysm Repair: If an aneurysm causes a stroke, doctors may perform clipping or coil embolization to prevent further bleeding.
• Blood Pressure Management: Medications may be given to lower blood pressure and prevent further bleeding.

Stroke Rehabilitation and Recovery

Stroke rehabilitation is a crucial part of recovery, as it helps stroke patients regain function and independence. Stroke rehabilitation also prevents another stroke from occurring. Rehabilitation programs are tailored to each patient’s specific needs and may include:

• Physical Therapy: Helps improve motor skills, strength, and coordination.
• Occupational Therapy: Focuses on improving daily living activities, such as dressing, eating, and bathing.
• Speech Therapy: Addresses communication difficulties and helps patients regain language skills.
• Psychological Support: Depression and anxiety are common after a stroke. Mental health support and counselling are essential for emotional well-being.
• Lifestyle Modifications: Adopting healthier habits, such as exercising regularly, eating a balanced diet, and quitting smoking, can prevent future strokes.

Preventing Stroke

While some risk factors for stroke, such as age and genetics, cannot be changed, many strokes can be prevented by adopting a healthier lifestyle. Here are some stroke prevention strategies:

• Control Blood Pressure: High blood pressure is the leading cause of stroke. Managing it through medications and lifestyle changes significantly reduces your risk.
• Quit Smoking: Smoking increases your risk of stroke. Quitting smoking can improve your overall health and reduce the likelihood of stroke.
• Maintain a Healthy Weight: Being overweight increases your risk of stroke. Regular exercise and a balanced diet can help you lose weight and maintain a healthy body.
• Manage Cholesterol: High cholesterol contributes to plaque development in the arteries. Eating a heart-healthy diet and taking cholesterol-lowering medications, if necessary, can reduce your stroke risk.
• Control Diabetes: If you have diabetes, controlling your blood sugar is essential to prevent stroke.
• Limit Alcohol Consumption: Excessive alcohol consumption can increase blood pressure and contribute to obesity. Limiting alcohol intake can reduce stroke risk.

Conclusion

A stroke is a life-threatening medical emergency that can have devastating consequences. However, many strokes are preventable through healthy lifestyle choices and proper management of risk factors. Early recognition of symptoms and prompt medical treatment can save lives and reduce the risk of long-term disability. If you or a loved one experiences stroke symptoms, act quickly and seek medical help immediately.