STROKE (Cerebrovascular Accident)

Stroke was defined by World Health Organisation (WHO) as a clinical syndrome consisting of rapidly evolving clinical signs of focal (at times global) disturbance of cerebral function lasting more than 24 hours or leading to death with no apparent cause other than of vascular origin. A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain either bursts, ruptures or is blocked by a clot. As a result, the brain cannot get the blood and oxygen it needs and pieces of the brain die.

CLASSIFICATION

Stroke can be classified into two major groups;

1.         Ischemic stroke

2.         Haemorrhagic stroke

Ischemic Strokes

 This type of stroke is caused by interruption of blood supply to parts of the brain, hence leading to the dysfunction of brain tissues in that area. There are four reasons leading to this type of stroke:

a.        Thrombosis – obstruction of a blood vessel by a blood clot(thrombus) forming locally

b.        Embolism – obstruction of blood vessel by a blood clot (Embolus) from elsewhere in the body

c.         Systemic hypoperfusion – general decrease in blood supply (e.g., in shock)

d.        Cerebral venous sinus thrombosis – presence of acute thrombosis in the dural venous sinuses which drain blood from the brain

Haemorrhagic Stroke

Here strokes result from rupture of blood vessels or an abnormal vascular structure. There are two main types of haemorrhagic strokes:

a.        Cerebral Haemorrhage – (aka intracerebral haemorrhage), which is basically bleeding within the brain due to either, intraparenchymal haemorrhage (bleeding within brain tissues) or intraventricular haemorrhage (bleeding within the ventricular system of the brain).

b.        Subarachnoid haemorrhage – this is basically bleeding that occurs outside of the brain tissue but still within the skull, and precisely between arachnoid mater and pia mater

Haemorrhagic stroke may occur as result of abnormal vascular structures, such as, amyloid angiopathy, cerebral arteriovenous malformation and intracranial aneurysm.

When the origin of stroke is unknown, it is referred to as cryptogenic stroke.

RISK FACTORS

 Knowing your risk factors for stroke is the first step in preventing a stroke. You can change or treat some risk factors, but others you can’t. By having regular medical check-ups and knowing your risk, you can focus on what you can change and lower your risk of stroke.

Modifiable

• High blood pressure. This is the single most important risk factor for stroke because it’s the No. 1 cause of stroke. Know your blood pressure and have it checked at least once every two weeks. Normal blood pressure is below 120/80. If it’s consistently 140/90 or above, it’s too high. Talk to your doctor about how to manage it.

• Tobacco use. Tobacco use damages blood vessels. This can lead to blockages within those blood vessels, causing a stroke. Do not smoke and avoid second-hand smoke.

• Diabetes. Having diabetes increases your risk of stroke because it can cause disease of blood vessels in the brain. Work with your doctor to manage diabetes.

• High cholesterol. High cholesterol increases the risk of blocked arteries. If an artery leading to the brain becomes blocked, a stroke can result.

• Physical inactivity and obesity. Being inactive, obese, or both, can increase your risk of cardiovascular disease.

• Carotid or other artery disease. The carotid arteries in your neck supply most of the blood to your brain. A carotid artery damaged by a fatty build-up of plaque inside the artery wall may become blocked by a blood clot. This causes a stroke.

• Transient ischemic attacks (TIAs). Recognizing and treating TIAs can reduce the risk of a major stroke. TIAs produce stroke-like symptoms but most have no lasting effects. Know the warning signs of a TIA and seek emergency medical treatment immediately. Approximately 15 percent of all strokes occur after a TIA.

• Atrial fibrillation (AFib) or other heart disease. In AFib the heart’s upper chambers quiver (like a bowl of gelatine) rather than beating in an organized, rhythmic way. This causes the blood to pool and clot, increasing the risk of stroke. AFib increases risk of stroke five times. People with other types of heart disease (eg. infective endocarditis, mitral stenosis, recent large MI, left ventricular hypertrophy) have a higher risk of stroke, too.

• Certain blood disorders. A high red blood cell count makes clots more likely, raising the risk of stroke. Sickle cell anaemia increases stroke risk because the “sickled” cells stick to blood vessel walls and may block arteries.

• Excessive alcohol intake. Drinking an average of more than one drink per day for women or more than two drinks a day for men can raise blood pressure. Binge drinking can lead to stroke.

• Illegal drug use. Intravenous drug use carries a high stroke risk. Cocaine use also has been linked to stroke. Illegal drugs commonly cause haemorrhagic strokes.

Non-Modifiable 

• Increasing age. Stroke affects people of all ages. But the older you are, the greater your stroke risk.

• Gender. In most age groups, more men than women have stroke, but more women die from stroke.

• Heredity and race. People whose close blood relations have had a stroke have a higher risk of stroke. African Americans have a higher risk of death and disability from stroke than whites. This is because they have high blood pressure more often. Hispanic Americans are also at higher risk of stroke.

• Prior stroke. Someone who has had a stroke is at higher risk of having another one.

SIGNS AND SYMPTOMS

Below are the warning signs of stroke;

Face Drooping: Does one side of the face droop or is it numb? Ask the person to smile.

Arm Weakness: Is one arm weak or numb? Ask the person to raise both arms. Does one arm drift downward?

Speech Difficulty: Is speech slurred, are they unable to speak, or are they hard to understand? Ask the person to repeat a simple sentence, like "the sky is blue." Is the sentence repeated correctly?

Time to get help: If the person shows any of these symptoms, even if the symptoms go away, get to the hospital right away and get help.

Other signs and symptoms include;

•          Sudden numbness or weakness in the leg especially on one side of the body

•          Sudden confusion and difficulty in understanding speech

•          Sudden trouble walking, dizziness, loss of balance or lack of coordination

•          Sudden severe headache with no apparent cause

Modifiable

• High blood pressure. This is the single most important risk factor for stroke because it’s the No. 1 cause of stroke. Know your blood pressure and have it checked at least once every two years. Normal blood pressure is below 120/80. If it’s consistently 140/90 or above, it’s too high. Talk to your doctor about how to manage it.

• Tobacco use. Tobacco use damages blood vessels. This can lead to blockages within those blood vessels, causing a stroke. Do not smoke and avoid second-hand smoke.

• Diabetes. Having diabetes increases your risk of stroke because it can cause disease of blood vessels in the brain. Work with your doctor to manage diabetes.

• High cholesterol. High cholesterol increases the risk of blocked arteries. If an artery leading to the brain becomes blocked, a stroke can result.

• Physical inactivity and obesity. Being inactive, obese, or both, can increase your risk of cardiovascular disease.

• Carotid or other artery disease. The carotid arteries in your neck supply most of the blood to your brain. A carotid artery damaged by a fatty build-up of plaque inside the artery wall may become blocked by a blood clot. This causes a stroke.

• Transient ischemic attacks (TIAs). Recognizing and treating TIAs can reduce the risk of a major stroke. TIAs produce stroke-like symptoms but most have no lasting effects. Know the warning signs of a TIA and seek emergency medical treatment immediately. Approximately 15 percent of all strokes occur after a TIA.

• Atrial fibrillation (AFib) or other heart disease. In AFib the heart’s upper chambers quiver (like a bowl of gelatine) rather than beating in an organized, rhythmic way. This causes the blood to pool and clot, increasing the risk of stroke. AFib increases risk of stroke five times. People with other types of heart disease (eg. infective endocarditis, mitral stenosis, recent large MI, left ventricular hypertrophy) have a higher risk of stroke, too.

• Certain blood disorders. A high red blood cell count makes clots more likely, raising the risk of stroke. Sickle cell anaemia increases stroke risk because the “sickled” cells stick to blood vessel walls and may block arteries.

• Excessive alcohol intake. Drinking an average of more than one drink per day for women or more than two drinks a day for men can raise blood pressure. Binge drinking can lead to stroke.

• Illegal drug use. Intravenous drug use carries a high stroke risk. Cocaine use also has been linked to stroke. Illegal drugs commonly cause haemorrhagic strokes.

Non-Modifiable

• Increasing age. Stroke affects people of all ages. But the older you are, the greater your stroke risk.

• Gender. In most age groups, more men than women have stroke, but more women die from stroke.

• Heredity and race. People whose close blood relations have had a stroke have a higher risk of stroke. African Americans have a higher risk of death and disability from stroke than whites. This is because they have high blood pressure more often. Hispanic Americans are also at higher risk of stroke.

• Prior stroke. Someone who has had a stroke is at higher risk of having another one.

SIGNS AND SYMPTOMS

Below are the warning signs of stroke;

Face Drooping: Does one side of the face droop or is it numb? Ask the person to smile.

Arm Weakness: Is one arm weak or numb? Ask the person to raise both arms. Does one arm drift downward?

Speech Difficulty: Is speech slurred, are they unable to speak, or are they hard to understand? Ask the person to repeat a simple sentence, like "the sky is blue." Is the sentence repeated correctly?

Time to seek for treatment: If the person shows any of these symptoms, even if the symptoms go away, get to the hospital right away and get help.

Other signs and symptoms include;

•          Sudden numbness or weakness in the leg especially on one side of the body

•          Sudden confusion and difficulty in understanding speech

•          Sudden trouble walking, dizziness, loss of balance or lack of coordination

•          Sudden severe headache with no apparent cause

Author: Orji, Emmanuel
Physiologist