Types of Stroke

Stroke can be broadly classified into two major categories: hemorrhagic stroke and ischemic stroke.

Hemorrhagic stroke accounts for approximately one-quarter of all strokes and is most commonly caused by hypertension or structural abnormalities of intracranial blood vessels, such as cerebral aneurysms.

Ischemic stroke accounts for approximately three-quarters of all cases and results from obstruction of cerebral blood flow. Common causes include large artery stenosis (such as carotid artery or intracranial artery disease), small vessel occlusion, and embolic events caused by atrial fibrillation, cancer, or coagulation abnormalities associated with severe infection.

Regardless of the underlying mechanism, interruption of blood supply or bleeding into the brain leads to neuronal injury and may result in permanent neurological deficits and disability.

Risk Factors

Stroke rarely occurs without warning. Instead, it is usually the consequence of years of accumulated vascular risk factors.

1. Hypertension, Diabetes Mellitus, and Hyperlipidemia

Long-standing hypertension accelerates arterial stiffening and narrowing while also increasing the risk of intracerebral hemorrhage. Elevated blood glucose and high levels of low-density lipoprotein (LDL) cholesterol promote vascular inflammation and endothelial injury, eventually leading to atherosclerosis.
2. Metabolic Syndrome and Physical Inactivity

Metabolic syndrome is diagnosed when three or more of the following five criteria are present:

Abdominal obesity
Elevated blood pressure
Fasting plasma glucose >100 mg/dL
Fasting triglycerides >150 mg/dL
Reduced high-density lipoprotein (HDL) cholesterol
Compared with the general population, individuals with metabolic syndrome have approximately a six-fold higher risk of developing diabetes mellitus, a four-fold higher risk of hypertension, a three-fold higher risk of hyperlipidemia, and nearly double the risk of stroke. Regular exercise combined with a healthy diet is among the most effective ways to prevent metabolic syndrome.
3. Smoking

Nicotine increases blood pressure and accelerates atherosclerosis, thereby increasing the risk of stroke.

4. Alcohol Consumption

Excessive alcohol intake may elevate blood pressure and cause dehydration. Many Asians also have reduced alcohol tolerance due to slower acetaldehyde metabolism, allowing acetaldehyde to accumulate in the body. This may damage both blood vessels and the nervous system.

5. Atrial Fibrillation

Atrial fibrillation causes blood flow stasis and turbulence within the atria, promoting thrombus formation that may subsequently embolize to the brain.

6. Obstructive Sleep Apnea

Many people are unaware that poor sleep quality and habitual snoring are associated with stroke. Studies have shown that obstructive sleep apnea causes intermittent nocturnal hypoxia, which damages the cardiovascular system and increases stroke risk by approximately two- to three-fold.

Stroke Prevention

Once the risk factors are understood, effective prevention becomes possible.

1. Exercise Regularly

Exercise is one of the best "medicines" for preventing stroke. Taiwan's Health Promotion Administration recommends at least 30 minutes of physical activity every day. The total exercise time may be accumulated in multiple sessions, provided that each session lasts at least 10 minutes. For example, 30 minutes of daily exercise may be divided into two 15-minute sessions or three 10-minute sessions. Moderate-intensity exercise, during which you can still carry on a conversation while breathing slightly harder than usual, is recommended. Consistency is the key to protecting cardiovascular and cerebrovascular health.

2. Control Blood Pressure, Blood Sugar, and Blood Lipids

Regularly monitor your blood pressure and maintain a healthy diet that is low in salt and unhealthy fats while rich in fruits and vegetables. Limit sugary beverages, such as bubble tea with full sugar, and avoid deep-fried foods. Periodic screening of fasting blood glucose, glycated hemoglobin (HbA1c), and blood lipid levels helps detect metabolic abnormalities early. If hypertension, diabetes, or hyperlipidemia has already been diagnosed, adherence to your physician's recommendations and prescribed medications can effectively reduce stroke risk.

3. Quit Smoking and Limit Alcohol Consumption

Quitting smoking and reducing alcohol intake can be challenging. If needed, seek assistance from smoking cessation or alcohol cessation clinics.

4. Detect and Treat Atrial Fibrillation and Obstructive Sleep Apnea

These conditions are often overlooked but can be detected through routine health examinations, such as electrocardiography, or by symptoms such as habitual snoring. Consultation with a cardiologist or a pulmonologist can facilitate appropriate diagnosis and treatment.

How to Recognize a Stroke

Remember Taiwan's public stroke awareness slogan:

"Smile, Raise Both Arms, and Say Hello."

If you notice facial asymmetry while smiling, weakness or drift of one arm when both arms are raised, or slurred or abnormal speech, seek emergency medical attention immediately.

Stroke Treatment

Significant advances have been made in the acute treatment of ischemic stroke.

1. Intravenous Thrombolysis

Eligible patients who present within 4.5 hours of symptom onset may receive intravenous thrombolytic therapy to dissolve the clot and restore blood flow.

2. Mechanical Thrombectomy

Patients with acute large vessel occlusion may be eligible for endovascular mechanical thrombectomy within 24 hours of symptom onset, depending on imaging findings.

Secondary Prevention

Preventing recurrent stroke is the most important goal after an initial stroke. Long-term management includes strict control of vascular risk factors and adherence to prescribed medications, including antiplatelet agents or anticoagulants, antihypertensive drugs, glucose-lowering medications, and lipid-lowering therapy. Remember that these medications are prescribed to prevent another stroke. Even if symptoms have completely resolved, medications should never be discontinued without consulting your physician.

Conclusion

Although stroke is a potentially devastating disease, it is far from inevitable. Remember the stroke warning signs—"Smile, Raise Both Arms, and Say Hello." If any abnormality is observed, call emergency medical services immediately and seek prompt treatment to maximize the chance of recovery and minimize long-term disability. Regular exercise, control of blood pressure, blood glucose, and cholesterol, routine health examinations, smoking cessation, and moderation of alcohol consumption can all substantially reduce the risk of stroke and help protect lifelong brain health.