What Are The Signs Of Stroke?

• Weakness or paralysis of one side of the body
• Slurred speech or aphasia (difficulty using or understanding language)
• Visual problems
• Perceptual challenges
• Being tired
• Depression
• Exaggerated or inappropriate emotional responses such as anger, moaning, laughing or crying
• Memory challenges
• Changes in personality

What Are The Signs Of Stroke?

• Weakness or paralysis of one side of the body
• Slurred speech or aphasia (difficulty using or understanding language)
• Visual problems
• Perceptual challenges
• Being tired
• Depression
• Exaggerated or inappropriate emotional responses such as anger, moaning, laughing or crying
• Memory challenges
• Changes in personality

Anticoagulation to prevent blood clots and strokes

AF is one of the most important causes of stroke in the U.S. Warfarin (Coumadin) is a blood thinner that prevents the formation of blood clots. Studies in patients with chronic sustained AF and sporadic (paroxysmal) AF have shown that warfarin reduces strokes.
Aspirin is an anti-platelet agent. Platelets are elements in the blood that are necessary for blood clots to form. Aspirin can be considered a milder blood thinner than warfarin, but it is not as reliable as warfarin in preventing strokes in patients with AF. Some doctors prescribe aspirin to patients when the risk of bleeding from warfarin is believed to be too high and to patients who refuse to take warfarin. Young patients with lone AF who are not at an increased risk for stroke sometimes are given aspirin rather than warfarin.
Side effects of warfarin. There are some patients who are at increased risk for side effects from warfarin. Specifically:
Patients with active stomach ulcers can develop ulcer bleeding while on warfarin.
Elderly patients can experience hemorrhage into the brain while taking warfarin. The risk of hemorrhage is higher if the patient also has high blood pressure.
Elderly patients who are unsteady and/or accident-prone are at an increased risk for trauma that can result in excessive bleeding.
Because of these serious side effects, patients using warfarin must be closely monitored with clotting tests such as the INR. The INR is a blood test that measures the degree of blood thinning. (The higher the value for the INR, the thinner the blood.) In preventing strokes in patients with AF, the dose of warfarin is adjusted to achieve a "therapeutic range" of INR. INR values higher than the therapeutic range are associated with an increased risk for bleeding, while values below the therapeutic range are associated with a diminished effectiveness in preventing stroke. Patients who are unreliable or unwilling to be monitored with regular measurements of INR may be considered for aspirin treatment rather than warfarin.
The beneficial effect of warfarin in preventing strokes needs to be balanced against the risk of excessive bleeding if the blood becomes too thin.
Candidates for warfarin. Doctors recommend warfarin to most elderly patients 65 years of age or older with paroxysmal (recurrent episodes) or chronic sustained AF. On balance, elderly patients with AF are more likely to benefit from warfarin because they are at a particularly high risk for stroke.
Patients younger than 65 with AF, especially those with prior embolic strokes, significant diseases of the heart, diabetes mellitus, high blood pressure, heart failure, coronary artery disease of the heart, or abnormally enlarged atrial chambers also are candidates for warfarin.
Patients who are not candidates for warfarin. Patients who are not candidates for warfarin include:
Patients with conditions that increase the risk of excessive bleeding, such as patients with active ulcers or other bleeding lesions in the intestines
Elderly patients who are unsteady and/or accident-prone and who are at an increased risk for trauma that can result in excessive bleeding
Patients who are unreliable or unwilling to be monitored with regular INR measurements (for whom therapy with aspirin may be better)

Anticoagulation to prevent blood clots and strokes

AF is one of the most important causes of stroke in the U.S. Warfarin (Coumadin) is a blood thinner that prevents the formation of blood clots. Studies in patients with chronic sustained AF and sporadic (paroxysmal) AF have shown that warfarin reduces strokes.
Aspirin is an anti-platelet agent. Platelets are elements in the blood that are necessary for blood clots to form. Aspirin can be considered a milder blood thinner than warfarin, but it is not as reliable as warfarin in preventing strokes in patients with AF. Some doctors prescribe aspirin to patients when the risk of bleeding from warfarin is believed to be too high and to patients who refuse to take warfarin. Young patients with lone AF who are not at an increased risk for stroke sometimes are given aspirin rather than warfarin.
Side effects of warfarin. There are some patients who are at increased risk for side effects from warfarin. Specifically:
Patients with active stomach ulcers can develop ulcer bleeding while on warfarin.
Elderly patients can experience hemorrhage into the brain while taking warfarin. The risk of hemorrhage is higher if the patient also has high blood pressure.
Elderly patients who are unsteady and/or accident-prone are at an increased risk for trauma that can result in excessive bleeding.
Because of these serious side effects, patients using warfarin must be closely monitored with clotting tests such as the INR. The INR is a blood test that measures the degree of blood thinning. (The higher the value for the INR, the thinner the blood.) In preventing strokes in patients with AF, the dose of warfarin is adjusted to achieve a "therapeutic range" of INR. INR values higher than the therapeutic range are associated with an increased risk for bleeding, while values below the therapeutic range are associated with a diminished effectiveness in preventing stroke. Patients who are unreliable or unwilling to be monitored with regular measurements of INR may be considered for aspirin treatment rather than warfarin.
The beneficial effect of warfarin in preventing strokes needs to be balanced against the risk of excessive bleeding if the blood becomes too thin.
Candidates for warfarin. Doctors recommend warfarin to most elderly patients 65 years of age or older with paroxysmal (recurrent episodes) or chronic sustained AF. On balance, elderly patients with AF are more likely to benefit from warfarin because they are at a particularly high risk for stroke.
Patients younger than 65 with AF, especially those with prior embolic strokes, significant diseases of the heart, diabetes mellitus, high blood pressure, heart failure, coronary artery disease of the heart, or abnormally enlarged atrial chambers also are candidates for warfarin.
Patients who are not candidates for warfarin. Patients who are not candidates for warfarin include:
Patients with conditions that increase the risk of excessive bleeding, such as patients with active ulcers or other bleeding lesions in the intestines
Elderly patients who are unsteady and/or accident-prone and who are at an increased risk for trauma that can result in excessive bleeding
Patients who are unreliable or unwilling to be monitored with regular INR measurements (for whom therapy with aspirin may be better)

Anticoagulation to prevent blood clots and strokes

AF is one of the most important causes of stroke in the U.S. Warfarin (Coumadin) is a blood thinner that prevents the formation of blood clots. Studies in patients with chronic sustained AF and sporadic (paroxysmal) AF have shown that warfarin reduces strokes.
Aspirin is an anti-platelet agent. Platelets are elements in the blood that are necessary for blood clots to form. Aspirin can be considered a milder blood thinner than warfarin, but it is not as reliable as warfarin in preventing strokes in patients with AF. Some doctors prescribe aspirin to patients when the risk of bleeding from warfarin is believed to be too high and to patients who refuse to take warfarin. Young patients with lone AF who are not at an increased risk for stroke sometimes are given aspirin rather than warfarin.
Side effects of warfarin. There are some patients who are at increased risk for side effects from warfarin. Specifically:
Patients with active stomach ulcers can develop ulcer bleeding while on warfarin.
Elderly patients can experience hemorrhage into the brain while taking warfarin. The risk of hemorrhage is higher if the patient also has high blood pressure.
Elderly patients who are unsteady and/or accident-prone are at an increased risk for trauma that can result in excessive bleeding.
Because of these serious side effects, patients using warfarin must be closely monitored with clotting tests such as the INR. The INR is a blood test that measures the degree of blood thinning. (The higher the value for the INR, the thinner the blood.) In preventing strokes in patients with AF, the dose of warfarin is adjusted to achieve a "therapeutic range" of INR. INR values higher than the therapeutic range are associated with an increased risk for bleeding, while values below the therapeutic range are associated with a diminished effectiveness in preventing stroke. Patients who are unreliable or unwilling to be monitored with regular measurements of INR may be considered for aspirin treatment rather than warfarin.
The beneficial effect of warfarin in preventing strokes needs to be balanced against the risk of excessive bleeding if the blood becomes too thin.
Candidates for warfarin. Doctors recommend warfarin to most elderly patients 65 years of age or older with paroxysmal (recurrent episodes) or chronic sustained AF. On balance, elderly patients with AF are more likely to benefit from warfarin because they are at a particularly high risk for stroke.
Patients younger than 65 with AF, especially those with prior embolic strokes, significant diseases of the heart, diabetes mellitus, high blood pressure, heart failure, coronary artery disease of the heart, or abnormally enlarged atrial chambers also are candidates for warfarin.
Patients who are not candidates for warfarin. Patients who are not candidates for warfarin include:
Patients with conditions that increase the risk of excessive bleeding, such as patients with active ulcers or other bleeding lesions in the intestines
Elderly patients who are unsteady and/or accident-prone and who are at an increased risk for trauma that can result in excessive bleeding
Patients who are unreliable or unwilling to be monitored with regular INR measurements (for whom therapy with aspirin may be better)

What causes a stroke?

Stroke is a disease that affects the blood vessels that supply blood to the brain.
A stroke occurs when a blood vessel that brings oxygen and nutrients to the brain either bursts (hemorrhagic stroke) or is clogged by a blood clot or some other mass (ischemic stroke). When a rupture or blockage occurs, parts of the brain don't get the blood and oxygen they need. Without oxygen, nerve cells in the affected area of the brain can't work properly, and die within minutes. And when nerve cells can't work, the part of the body they control can't work either. The devastating effects of a severe stroke are often permanent because dead brain cells aren't replaced.
There are two main types of stroke. One (ischemic stroke) is caused by blockage of a blood vessel; the other (hemorrhagic stroke) is caused by bleeding. Bleeding strokes have a much higher death rate than strokes caused by clots.
What is ischemic stroke?
Ischemic stroke is the most common type. It accounts for about 87 percent of all strokes. It occurs when a blood clot (thrombus) forms and blocks blood flow in an artery bringing blood to part of the brain. Blood clots usually form in arteries damaged by fatty buildups, called atherosclerosis.
When the blood clot forms within an artery of the brain, it's called a thrombotic stroke. These often occur at night or first thing in the morning. Another distinguishing feature is that very often they're preceded by a transient ischemic attack. This is also called a TIA or "warning stroke." TIAs have the same symptoms of stroke but only last a few minutes; stroke symptoms last much longer. If someones experiences a TIA, they should urgent medical care immediately.
What is a cerebral embolism?
A wandering clot (an embolus) or some other particle that forms away from the brain, usually in the heart, may also cause an ischemic stroke. This is called cerebral embolism. The clot is carried by the bloodstream until it lodges in an artery leading to or in the brain, blocking the flow of blood.
The most common cause of these emboli is blood clots that form during atrial fibrillation (AF). AF is a disorder found in about 2.2 million Americans. It's responsible for 15–20 percent of all strokes. In AF, the heart's two small upper chambers (the atria) quiver like a bowl of jello instead of beating strongly and effectively. Some blood isn't pumped completely out of them when the heart beats, so it pools and clots can form. When a blood clot enters the circulation and lodges in a narrowed artery of the brain, a stroke occurs. This is called a cardioembolic stroke, or a stroke that occurs because of a heart problem.
What is hemorrhagic stroke?
A subarachnoid hemorrhage occurs when a blood vessel on the brain's surface ruptures and bleeds into the space between the brain and the skull (but not into the brain itself).
A cerebral hemorrhage occurs when a defective artery in the brain bursts, flooding the surrounding tissue with blood.
Hemorrhage (or bleeding) from an artery in the brain can be caused by a head injury or a burst aneurysm. Aneurysms are blood-filled pouches that balloon out from weak spots in the artery wall. They're often caused or made worse by high blood pressure. Aneurysms aren't always dangerous, but if one bursts in the brain, they cause a hemorrhagic stroke.
When a cerebral or subarachnoid hemorrhage occurs, the loss of a constant blood supply means some brain cells no longer can work. Accumulated blood from the burst artery also may put pressure on surrounding brain tissue and interfere with how the brain works. Severe or mild symptoms can result, depending on the amount of pressure.
The amount of bleeding determines the severity of cerebral hemorrhages. In many cases, people with cerebral hemorrhages die of increased pressure on their brains. But those who live tend to recover much more than people who've had strokes caused by a clot. That's because when a blood vessel is blocked, part of the brain dies — and the brain doesn't regenerate itself; in other words, brain cells can't be replaced. But when a blood vessel in the brain bursts, pressure from the blood compresses part of the brain. If the person survives, gradually the pressure goes away. Then the brain may regain some of its former function.

What causes a stroke?

Stroke is a disease that affects the blood vessels that supply blood to the brain.
A stroke occurs when a blood vessel that brings oxygen and nutrients to the brain either bursts (hemorrhagic stroke) or is clogged by a blood clot or some other mass (ischemic stroke). When a rupture or blockage occurs, parts of the brain don't get the blood and oxygen they need. Without oxygen, nerve cells in the affected area of the brain can't work properly, and die within minutes. And when nerve cells can't work, the part of the body they control can't work either. The devastating effects of a severe stroke are often permanent because dead brain cells aren't replaced.
There are two main types of stroke. One (ischemic stroke) is caused by blockage of a blood vessel; the other (hemorrhagic stroke) is caused by bleeding. Bleeding strokes have a much higher death rate than strokes caused by clots.
What is ischemic stroke?
Ischemic stroke is the most common type. It accounts for about 87 percent of all strokes. It occurs when a blood clot (thrombus) forms and blocks blood flow in an artery bringing blood to part of the brain. Blood clots usually form in arteries damaged by fatty buildups, called atherosclerosis.
When the blood clot forms within an artery of the brain, it's called a thrombotic stroke. These often occur at night or first thing in the morning. Another distinguishing feature is that very often they're preceded by a transient ischemic attack. This is also called a TIA or "warning stroke." TIAs have the same symptoms of stroke but only last a few minutes; stroke symptoms last much longer. If someones experiences a TIA, they should urgent medical care immediately.
What is a cerebral embolism?
A wandering clot (an embolus) or some other particle that forms away from the brain, usually in the heart, may also cause an ischemic stroke. This is called cerebral embolism. The clot is carried by the bloodstream until it lodges in an artery leading to or in the brain, blocking the flow of blood.
The most common cause of these emboli is blood clots that form during atrial fibrillation (AF). AF is a disorder found in about 2.2 million Americans. It's responsible for 15–20 percent of all strokes. In AF, the heart's two small upper chambers (the atria) quiver like a bowl of jello instead of beating strongly and effectively. Some blood isn't pumped completely out of them when the heart beats, so it pools and clots can form. When a blood clot enters the circulation and lodges in a narrowed artery of the brain, a stroke occurs. This is called a cardioembolic stroke, or a stroke that occurs because of a heart problem.
What is hemorrhagic stroke?
A subarachnoid hemorrhage occurs when a blood vessel on the brain's surface ruptures and bleeds into the space between the brain and the skull (but not into the brain itself).
A cerebral hemorrhage occurs when a defective artery in the brain bursts, flooding the surrounding tissue with blood.
Hemorrhage (or bleeding) from an artery in the brain can be caused by a head injury or a burst aneurysm. Aneurysms are blood-filled pouches that balloon out from weak spots in the artery wall. They're often caused or made worse by high blood pressure. Aneurysms aren't always dangerous, but if one bursts in the brain, they cause a hemorrhagic stroke.
When a cerebral or subarachnoid hemorrhage occurs, the loss of a constant blood supply means some brain cells no longer can work. Accumulated blood from the burst artery also may put pressure on surrounding brain tissue and interfere with how the brain works. Severe or mild symptoms can result, depending on the amount of pressure.
The amount of bleeding determines the severity of cerebral hemorrhages. In many cases, people with cerebral hemorrhages die of increased pressure on their brains. But those who live tend to recover much more than people who've had strokes caused by a clot. That's because when a blood vessel is blocked, part of the brain dies — and the brain doesn't regenerate itself; in other words, brain cells can't be replaced. But when a blood vessel in the brain bursts, pressure from the blood compresses part of the brain. If the person survives, gradually the pressure goes away. Then the brain may regain some of its former function.

What causes a stroke?

Stroke is a disease that affects the blood vessels that supply blood to the brain.
A stroke occurs when a blood vessel that brings oxygen and nutrients to the brain either bursts (hemorrhagic stroke) or is clogged by a blood clot or some other mass (ischemic stroke). When a rupture or blockage occurs, parts of the brain don't get the blood and oxygen they need. Without oxygen, nerve cells in the affected area of the brain can't work properly, and die within minutes. And when nerve cells can't work, the part of the body they control can't work either. The devastating effects of a severe stroke are often permanent because dead brain cells aren't replaced.
There are two main types of stroke. One (ischemic stroke) is caused by blockage of a blood vessel; the other (hemorrhagic stroke) is caused by bleeding. Bleeding strokes have a much higher death rate than strokes caused by clots.
What is ischemic stroke?
Ischemic stroke is the most common type. It accounts for about 87 percent of all strokes. It occurs when a blood clot (thrombus) forms and blocks blood flow in an artery bringing blood to part of the brain. Blood clots usually form in arteries damaged by fatty buildups, called atherosclerosis.
When the blood clot forms within an artery of the brain, it's called a thrombotic stroke. These often occur at night or first thing in the morning. Another distinguishing feature is that very often they're preceded by a transient ischemic attack. This is also called a TIA or "warning stroke." TIAs have the same symptoms of stroke but only last a few minutes; stroke symptoms last much longer. If someones experiences a TIA, they should urgent medical care immediately.
What is a cerebral embolism?
A wandering clot (an embolus) or some other particle that forms away from the brain, usually in the heart, may also cause an ischemic stroke. This is called cerebral embolism. The clot is carried by the bloodstream until it lodges in an artery leading to or in the brain, blocking the flow of blood.
The most common cause of these emboli is blood clots that form during atrial fibrillation (AF). AF is a disorder found in about 2.2 million Americans. It's responsible for 15–20 percent of all strokes. In AF, the heart's two small upper chambers (the atria) quiver like a bowl of jello instead of beating strongly and effectively. Some blood isn't pumped completely out of them when the heart beats, so it pools and clots can form. When a blood clot enters the circulation and lodges in a narrowed artery of the brain, a stroke occurs. This is called a cardioembolic stroke, or a stroke that occurs because of a heart problem.
What is hemorrhagic stroke?
A subarachnoid hemorrhage occurs when a blood vessel on the brain's surface ruptures and bleeds into the space between the brain and the skull (but not into the brain itself).
A cerebral hemorrhage occurs when a defective artery in the brain bursts, flooding the surrounding tissue with blood.
Hemorrhage (or bleeding) from an artery in the brain can be caused by a head injury or a burst aneurysm. Aneurysms are blood-filled pouches that balloon out from weak spots in the artery wall. They're often caused or made worse by high blood pressure. Aneurysms aren't always dangerous, but if one bursts in the brain, they cause a hemorrhagic stroke.
When a cerebral or subarachnoid hemorrhage occurs, the loss of a constant blood supply means some brain cells no longer can work. Accumulated blood from the burst artery also may put pressure on surrounding brain tissue and interfere with how the brain works. Severe or mild symptoms can result, depending on the amount of pressure.
The amount of bleeding determines the severity of cerebral hemorrhages. In many cases, people with cerebral hemorrhages die of increased pressure on their brains. But those who live tend to recover much more than people who've had strokes caused by a clot. That's because when a blood vessel is blocked, part of the brain dies — and the brain doesn't regenerate itself; in other words, brain cells can't be replaced. But when a blood vessel in the brain bursts, pressure from the blood compresses part of the brain. If the person survives, gradually the pressure goes away. Then the brain may regain some of its former function.

Stroke - signs and symptoms

What is a stroke?
A stroke is when an area of the brain is deprived of its blood supply - usually because of a blockage or burst blood vessel - for long enough to cause vital brain tissue to die. It's essentially the same as what happens in the arteries leading to the heart when someone has a heart attack, which is why a stroke is now often described as a 'brain attack'.
If brain cells lose their supply of oxygen from the blood, they may be damaged or die. When this happens, it's so sudden there's little medical science can do to prevent it.
Dead brain cells can't start working again. However, surrounding these dead cells is an area of tissue where blood supply is poor but not lost completely, so the nerve cells are receiving barely enough oxygen to stay alive.
One of the main aims of treating a stroke is to act fast enough to save this threatened brain tissue by restoring blood flow to the area and minimising the damage. As the inflammation and swelling caused by the stroke subside, brain cells near the dead cells may recover and begin working again.
There are two main types of stroke:
Ischaemic stroke
In this, the most common type of stroke, the artery is blocked by a blood clot, which interrupts the brain's blood supply.
This may be due to a cerebral thrombosis (sometimes called a thrombotic stroke), where a blood clot forms in one of the main arteries leading to the brain, or to a cerebral embolism (sometimes called an embolic stroke), in which a blood clot forms elsewhere in the body and is swept into the arteries serving the brain.
Fatty tissue or air bubbles may also form emboli which cause stroke, especially after major trauma.
Another type of thrombotic ischaemic stroke is called a lacunar stroke. In this form, one of the tiny blood vessels deep inside the brain tissue becomes blocked, leading to the death of the small area of tissue that it supplies. Lacunar strokes are usually less severe.
Haemorrhagic stroke
In this type of stroke, a blood vessel in or around the brain ruptures causing bleeding, or a haemorrhage. The build-up of blood presses on the brain, damaging its delicate tissue. Meanwhile, other brain cells in the area are starved of blood and damaged.
In an intracerebral haemorrhage, the bleeding occurs inside the brain itself. In a subarachnoid haemorrage, the burst blood vessel bleeds into the subarachnoid space surrounding the brain.
Transient ischaemic attack (TIA)
A transient ischaemic attack, often known as a mini-stroke, is a brief episode where some brain function is temporarily lost because of a short-lived disruption of the blood supply.
Symptoms, such as weakness of a limb, last for just minutes (typically two to 15 minutes) before the blood supply returns and everything returns to normal, because the brain cells haven't suffered permanent damage.
Traditionally it has been said that if symptoms last less than 24 hours it's a TIA, but when symptoms persist for more than 24 hours then a stroke has occurred. But with more powerful and sophisticated brain-scanning techniques, it has become possible to show that permanent damage (the real hallmark of a stroke) can usually be detected when symptoms last more than an hour or so.
TIAs are an important warning sign that all is not well with the blood supply to the brain. The risk of suffering a complete stroke within the first month after a TIA may be as high as 20 per cent, with the risk being even greater in the first few days following a TIA.
Why the brain needs a constant blood supply
The brain is the most complex organ in the body. It regulates absolutely everything your body does - breathing, moving, sweating, sleeping, waking, feeling, your moods, thoughts and speech.
To perform all these functions, the brain must have a constant supply of blood to deliver oxygen and nutrients to the brain cells. If the blood supply fails, as in a stroke, the brain cells become damaged or die within a very short space of time. Unlike other cells in the body, once they've died brain cells can't regrow.
What are the causes?
Each type of stroke has different causes. They include:
Diseased arteries - blockage of the arteries is usually the result of athersclerosis, furring and narrowing of the artery walls with a mixture of cholesterol and other debris.
Aneurysm - a weakened spot on an artery wall causes it to stretch. The vessel wall may become so thin it bursts, causing bleeding into the brain (haemmorhagic stroke).
Atrial fibrillation - this kind of irregular heartbeat (arrhythmia) can cause a blood clot to form in the heart, which then travels to the brain.

Stroke - signs and symptoms

What is a stroke?
A stroke is when an area of the brain is deprived of its blood supply - usually because of a blockage or burst blood vessel - for long enough to cause vital brain tissue to die. It's essentially the same as what happens in the arteries leading to the heart when someone has a heart attack, which is why a stroke is now often described as a 'brain attack'.
If brain cells lose their supply of oxygen from the blood, they may be damaged or die. When this happens, it's so sudden there's little medical science can do to prevent it.
Dead brain cells can't start working again. However, surrounding these dead cells is an area of tissue where blood supply is poor but not lost completely, so the nerve cells are receiving barely enough oxygen to stay alive.
One of the main aims of treating a stroke is to act fast enough to save this threatened brain tissue by restoring blood flow to the area and minimising the damage. As the inflammation and swelling caused by the stroke subside, brain cells near the dead cells may recover and begin working again.
There are two main types of stroke:
Ischaemic stroke
In this, the most common type of stroke, the artery is blocked by a blood clot, which interrupts the brain's blood supply.
This may be due to a cerebral thrombosis (sometimes called a thrombotic stroke), where a blood clot forms in one of the main arteries leading to the brain, or to a cerebral embolism (sometimes called an embolic stroke), in which a blood clot forms elsewhere in the body and is swept into the arteries serving the brain.
Fatty tissue or air bubbles may also form emboli which cause stroke, especially after major trauma.
Another type of thrombotic ischaemic stroke is called a lacunar stroke. In this form, one of the tiny blood vessels deep inside the brain tissue becomes blocked, leading to the death of the small area of tissue that it supplies. Lacunar strokes are usually less severe.
Haemorrhagic stroke
In this type of stroke, a blood vessel in or around the brain ruptures causing bleeding, or a haemorrhage. The build-up of blood presses on the brain, damaging its delicate tissue. Meanwhile, other brain cells in the area are starved of blood and damaged.
In an intracerebral haemorrhage, the bleeding occurs inside the brain itself. In a subarachnoid haemorrage, the burst blood vessel bleeds into the subarachnoid space surrounding the brain.
Transient ischaemic attack (TIA)
A transient ischaemic attack, often known as a mini-stroke, is a brief episode where some brain function is temporarily lost because of a short-lived disruption of the blood supply.
Symptoms, such as weakness of a limb, last for just minutes (typically two to 15 minutes) before the blood supply returns and everything returns to normal, because the brain cells haven't suffered permanent damage.
Traditionally it has been said that if symptoms last less than 24 hours it's a TIA, but when symptoms persist for more than 24 hours then a stroke has occurred. But with more powerful and sophisticated brain-scanning techniques, it has become possible to show that permanent damage (the real hallmark of a stroke) can usually be detected when symptoms last more than an hour or so.
TIAs are an important warning sign that all is not well with the blood supply to the brain. The risk of suffering a complete stroke within the first month after a TIA may be as high as 20 per cent, with the risk being even greater in the first few days following a TIA.
Why the brain needs a constant blood supply
The brain is the most complex organ in the body. It regulates absolutely everything your body does - breathing, moving, sweating, sleeping, waking, feeling, your moods, thoughts and speech.
To perform all these functions, the brain must have a constant supply of blood to deliver oxygen and nutrients to the brain cells. If the blood supply fails, as in a stroke, the brain cells become damaged or die within a very short space of time. Unlike other cells in the body, once they've died brain cells can't regrow.
What are the causes?
Each type of stroke has different causes. They include:
Diseased arteries - blockage of the arteries is usually the result of athersclerosis, furring and narrowing of the artery walls with a mixture of cholesterol and other debris.
Aneurysm - a weakened spot on an artery wall causes it to stretch. The vessel wall may become so thin it bursts, causing bleeding into the brain (haemmorhagic stroke).
Atrial fibrillation - this kind of irregular heartbeat (arrhythmia) can cause a blood clot to form in the heart, which then travels to the brain.

Stroke - signs and symptoms

What is a stroke?
A stroke is when an area of the brain is deprived of its blood supply - usually because of a blockage or burst blood vessel - for long enough to cause vital brain tissue to die. It's essentially the same as what happens in the arteries leading to the heart when someone has a heart attack, which is why a stroke is now often described as a 'brain attack'.
If brain cells lose their supply of oxygen from the blood, they may be damaged or die. When this happens, it's so sudden there's little medical science can do to prevent it.
Dead brain cells can't start working again. However, surrounding these dead cells is an area of tissue where blood supply is poor but not lost completely, so the nerve cells are receiving barely enough oxygen to stay alive.
One of the main aims of treating a stroke is to act fast enough to save this threatened brain tissue by restoring blood flow to the area and minimising the damage. As the inflammation and swelling caused by the stroke subside, brain cells near the dead cells may recover and begin working again.
There are two main types of stroke:
Ischaemic stroke
In this, the most common type of stroke, the artery is blocked by a blood clot, which interrupts the brain's blood supply.
This may be due to a cerebral thrombosis (sometimes called a thrombotic stroke), where a blood clot forms in one of the main arteries leading to the brain, or to a cerebral embolism (sometimes called an embolic stroke), in which a blood clot forms elsewhere in the body and is swept into the arteries serving the brain.
Fatty tissue or air bubbles may also form emboli which cause stroke, especially after major trauma.
Another type of thrombotic ischaemic stroke is called a lacunar stroke. In this form, one of the tiny blood vessels deep inside the brain tissue becomes blocked, leading to the death of the small area of tissue that it supplies. Lacunar strokes are usually less severe.
Haemorrhagic stroke
In this type of stroke, a blood vessel in or around the brain ruptures causing bleeding, or a haemorrhage. The build-up of blood presses on the brain, damaging its delicate tissue. Meanwhile, other brain cells in the area are starved of blood and damaged.
In an intracerebral haemorrhage, the bleeding occurs inside the brain itself. In a subarachnoid haemorrage, the burst blood vessel bleeds into the subarachnoid space surrounding the brain.
Transient ischaemic attack (TIA)
A transient ischaemic attack, often known as a mini-stroke, is a brief episode where some brain function is temporarily lost because of a short-lived disruption of the blood supply.
Symptoms, such as weakness of a limb, last for just minutes (typically two to 15 minutes) before the blood supply returns and everything returns to normal, because the brain cells haven't suffered permanent damage.
Traditionally it has been said that if symptoms last less than 24 hours it's a TIA, but when symptoms persist for more than 24 hours then a stroke has occurred. But with more powerful and sophisticated brain-scanning techniques, it has become possible to show that permanent damage (the real hallmark of a stroke) can usually be detected when symptoms last more than an hour or so.
TIAs are an important warning sign that all is not well with the blood supply to the brain. The risk of suffering a complete stroke within the first month after a TIA may be as high as 20 per cent, with the risk being even greater in the first few days following a TIA.
Why the brain needs a constant blood supply
The brain is the most complex organ in the body. It regulates absolutely everything your body does - breathing, moving, sweating, sleeping, waking, feeling, your moods, thoughts and speech.
To perform all these functions, the brain must have a constant supply of blood to deliver oxygen and nutrients to the brain cells. If the blood supply fails, as in a stroke, the brain cells become damaged or die within a very short space of time. Unlike other cells in the body, once they've died brain cells can't regrow.
What are the causes?
Each type of stroke has different causes. They include:
Diseased arteries - blockage of the arteries is usually the result of athersclerosis, furring and narrowing of the artery walls with a mixture of cholesterol and other debris.
Aneurysm - a weakened spot on an artery wall causes it to stretch. The vessel wall may become so thin it bursts, causing bleeding into the brain (haemmorhagic stroke).
Atrial fibrillation - this kind of irregular heartbeat (arrhythmia) can cause a blood clot to form in the heart, which then travels to the brain.