Stroke

There are two main categories of strokes. Ischemic (top), typically caused by a blood clot in an artery (1a) resulting in brain death to the affected area (2a). Hemorrhagic (bottom), caused by blood leaking into or around the brain from a ruptured blood vessel (1b) allowing blood to pool in the affected area (2b) thus increasing the pressure on the brain.

A slice of brain from the autopsy of a person who had an acute middle cerebral artery (MCA) stroke

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Stroke deaths per million persons in 2012

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Disability-adjusted life year

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CT scan of an intraparenchymal bleed (bottom arrow) with surrounding edema (top arrow)

Illustration of an embolic stroke, showing a blockage lodged in a blood vessel.

A CT showing early signs of a middle cerebral artery stroke with loss of definition of the gyri and grey white boundary

Dens media sign in a patient with middle cerebral artery infarction shown on the left. Right image after 7 hours.

A stroke is a medical emergency characterized by the sudden disruption of blood flow to the brain, resulting in rapid cell death and potentially long-lasting neurological damage. Strokes can be classified into two main types: ischemic stroke, which occurs when a blood clot obstructs blood flow in a brain artery, and hemorrhagic stroke, which is caused by the rupture of a blood vessel in the brain. The primary symptoms of a stroke include sudden onset of weakness, numbness, difficulty speaking, loss of coordination, and vision changes. Immediate medical attention is crucial for stroke patients, as timely intervention can greatly improve outcomes and reduce the risk of permanent disability or death.

Causes

Ischemic Stroke

Ischemic strokes are the most common type of stroke, accounting for about 87% of all cases. They occur when a blood clot blocks blood flow to the brain. The two main subtypes of ischemic strokes are:

Thrombotic stroke: A clot (thrombus) forms in an artery supplying blood to the brain. This is often associated with atherosclerosis, the buildup of fatty deposits on the artery walls. Embolic stroke: A clot (embolus) forms elsewhere in the body and travels through the bloodstream, eventually lodging in a narrow brain artery. Common sources of emboli include the heart and the carotid arteries.

Hemorrhagic Stroke

Hemorrhagic strokes account for the remaining 13% of cases and occur when a blood vessel in the brain ruptures. There are two main types of hemorrhagic strokes:

Intracerebral hemorrhage: Bleeding occurs within the brain tissue itself, often due to hypertension (high blood pressure) or arteriovenous malformations (abnormal connections between arteries and veins). Subarachnoid hemorrhage: Bleeding occurs in the subarachnoid space, the area between the brain and the skull. This type of hemorrhage is usually caused by the rupture of a cerebral aneurysm (a weakened area in an artery wall).

Symptoms

The sudden onset of the following symptoms may indicate a stroke:

Weakness or numbness on one side of the body Difficulty speaking or understanding speech Loss of coordination or balance Sudden severe headache with no known cause Vision changes, such as blurring or loss of vision in one or both eyes It is crucial to recognize these symptoms and seek immediate medical attention, as the effectiveness of stroke treatments decreases with time.

Diagnosis

A stroke is typically diagnosed using a combination of a physical examination, a neurological assessment, and imaging studies. Imaging tests may include:

Computed tomography (CT) scan: This is often the first test performed, as it can quickly identify the presence of bleeding in the brain. Magnetic resonance imaging (MRI): This test provides more detailed images of the brain and can help determine the cause and extent of the stroke. CT angiography or MR angiography: These tests visualize the blood vessels in the brain and can help identify the location of a clot or aneurysm. Additional tests, such as blood tests, an electrocardiogram (ECG), or an echocardiogram, may be performed to help identify the underlying cause of the stroke and guide treatment decisions.

Treatment

The treatment for a stroke depends on its type and severity. Early intervention is crucial to minimize brain damage and potential long-term complications.

Ischemic Stroke

Thrombolytic therapy: Administering a clot-dissolving medication, such as tissue plasminogen activator (tPA), can help restore blood flow to the brain by breaking up the clot. This treatment is most effective when administered within 3 to 4.5 hours of the onset of symptoms.

Anticoagulant medications: Drugs such as heparin or warfarin may be prescribed to help prevent the formation of new clots. Antiplatelet medications: Aspirin and other antiplatelet drugs can help prevent the formation of blood clots and may be given to reduce the risk of a recurrent stroke. Endovascular procedures: In some cases, a catheter may be inserted into an artery and guided to the site of the clot to remove it or deliver clot-dissolving medication directly.

Hemorrhagic Stroke

Blood pressure management: Controlling high blood pressure is crucial to prevent further bleeding and minimize damage. Surgery: In some cases, surgical intervention may be necessary to repair a ruptured aneurysm, remove a blood clot, or relieve pressure on the brain caused by swelling. Coiling or clipping: These are minimally invasive procedures that can be used to block blood flow to an aneurysm, preventing it from rupturing or re-bleeding.

Rehabilitation

Stroke rehabilitation is an essential part of recovery and typically begins as soon as the patient is medically stable. Rehabilitation programs may include:

Physical therapy: To help restore movement, strength, and coordination Occupational therapy: To help relearn daily activities and improve independence Speech therapy: To address difficulties with speech and swallowing Cognitive therapy: To improve memory, attention, and problem-solving skills Psychological counseling: To address emotional and mental health challenges Rehabilitation is often a long-term process, with the goal of maximizing the patient's independence and quality of life.

Prevention

Preventing a stroke involves managing risk factors and adopting a healthy lifestyle. Some strategies for reducing the risk of stroke include:

• Maintaining a healthy diet: A diet rich in fruits, vegetables, whole grains, lean proteins, and low-fat dairy products can help lower the risk of stroke.
• Regular exercise: Engaging in regular physical activity can help maintain a healthy weight and reduce blood pressure.
• Quitting smoking: Smoking is a major risk factor for stroke, and quitting can significantly lower the risk.
• Managing blood pressure: High blood pressure is a leading cause of stroke, and controlling it through medication and lifestyle changes can significantly reduce the risk.
• Managing diabetes: High blood sugar levels can increase the risk of stroke, so maintaining tight control over blood sugar is essential for people with diabetes.
• Limiting alcohol consumption: Consuming alcohol in moderation can help reduce the risk of stroke. Moderate alcohol intake is generally defined as one drink per day for women and two drinks per day for men.
• By addressing these risk factors and adopting a healthier lifestyle, individuals can greatly reduce their risk of experiencing a stroke.

See also

• Cerebrovascular disease
• Dejerine–Roussy syndrome
• Functional Independence Measure
• Lipoprotein(a)
• Mechanism of anoxic depolarization in the brain
• Ultrasound-enhanced systemic thrombolysis
• Weber's syndrome

External links

• Stroke at Curlie

• DRAGON Score for Post-Thrombolysis
• THRIVE score for stroke outcome
• National Institute of Neurological Disorders and Stroke

Classification	ICD-10: I61 -I64 ner ICD-9-CM: 434.91 OMIM: 601367 MeSH: D020521 DiseasesDB: 2247
External resources	MedlinePlus: 000726 eMedicine: neuro/9 emerg/558 emerg/557 pmr/187

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