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من طرف almhdom السبت أكتوبر 18, 2008 2:41 pm[center]Cerebru vascular accident
CVA))
Definition:-
A stroke is damage to part of the brain when its blood supply is suddenly reduced or stopped. Death of a part of the brain may lead to loss of certain body functions controlled by that affected part.
Types:-
There are two main types of stroke ischemic and hemorrhagic. Ischemic stroke is more common and occurs when blood flow to a part or parts of the brain is stopped by a blockage in a vessel. Hemorrhagic stroke is more deadly and occurs when a weakened vessel tears or ruptures, diverting blood flow from its normal course and instead leaking or spilling it into or around the brain itself.
(left) Illustration of Ischemic Stroke showing blockage of one of the brain's arteries.(right) CT scan of Hemorrhagic Stroke. Arrow points to the area of blood in the brain.
There is a third type referred to as transient ischemic attack (TIA), A TIA is caused by a brief pause in blood flow to part of the brain , the result of a temporary or partial blockage.
Ischemic stroke:-
The vast majority of strokes – approximately 83 percent — are ischemic. They are caused by an obstruction of an artery leading to or in the brain, preventing oxygenated blood from reaching parts of the brain that the artery feeds. Ischemic strokes are either thrombotic or embolic, depending on where the obstruction or clot (thrombus or embolism), causing the blockage originated:
Thrombotic Ischemic Stroke
Thrombotic stroke is caused by a thrombus (blood clot) that develops in an artery supplying blood to the brain — usually because of a repeated buildup of fatty deposits, calcium and clotting factors, such as fibrinogen and cholesterol, carried in the blood. The body perceives the buildup as an injury to the vessel wall and responds the way it would to a small wound — it forms blood clots. The blood clots get caught on the plaque on the vessel walls, eventually stopping blood flow.
There are two types of thrombotic stroke:
Large vessel thrombosis, the most common form of thrombotic stroke, occurs in the brain’s larger arteries.
In most cases, large vessel thrombosis is caused by a combination of long-term plaque buildup (atherosclerosis) followed by rapid blood clot formation. High cholesterol is a common risk factor for this type of stroke.
Small vessel disease (lacunar infarction) occurs when blood flow is blocked to a very small arterial vessel. It has been linked to high blood pressure (hypertension) and is an indicator of atherosclerotic disease.
Embolic Ischemic Stroke:-
A blood clot that forms in one area of the body and travels through the bloodstream to another where it may lodge is called an embolus. In the case of embolic stroke, the clot forms outside of the brain – usually in the heart or large arteries of the upper chest and neck – and is transported through the bloodstream to the brain. Emboli can be fat globules, air bubbles or, most commonly, bits and pieces of atherosclerotic plaque, such as lipid debris, that have detached from an artery wall. Many emboli are caused by a cardiac condition called atrial fibrillation.
Hemorrhagic stroke:-
Hemorrhagic stroke occurs when a vessel in the brain suddenly ruptures and blood begins to leak directly into brain tissue and/or into the clear cerebrospinal fluid that surrounds the brain and fills its central cavities (ventricles). The rupture can be caused by the force of high blood pressure. It can also originate from a weak spot in a blood vessel wall (a cerebral aneurysm) or other blood vessel malformation in or around the brain.
Damage can be caused in two ways. As in the case of ischemic stroke, oxygen- and nutrient-rich blood is prevented from reaching the brain cells beyond the point of rupture. In addition, leaked blood can irritate and harm the brain cells in the areas where it accumulates.
It is the location of the hemorrhage, rather than the amount of bleeding, that tends to be the bigger factor in influencing the severity of the stroke. For example, bleeds in the brainstem, though relatively tiny, can be quite lethal, whereas the same-sized bleed in the frontal lobe may not even be noticeable.
There are two types of hemorrhagic strokes. They are differentiated by where the ruptured artery is located and where the resulting blood leakage occurs.
Intracerebral Hemorrhage (ICH) or intracranial hematoma).
This type of stroke is caused by the sudden rupture of an artery or blood vessel within the brain. The blood that leaks into the brain results in a sudden increase in pressure that can damage the surrounding brain cells. If the amount of blood increases rapidly, the sudden and extreme buildup in pressure can lead to unconsciousness or death. They occur most commonly in the basal ganglia where the vessels can be particularly delicate.
High blood pressure (hypertension) is the most common cause of this type of stroke. Less common causes include trauma, infections, tumors, blood clotting deficiencies, and abnormalities in cerebral blood vessels.
Blood Vessel Abnormalities: Blood vessel abnormalities in the brain include arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs). AVMs and AVFs, also called lesions, are abnormal connections between cerebral arteries (which carry blood to the brain) and veins (which take blood away from the brain).
Subarachnoid Hemorrhage (SAH)
Subarachnoid hemorrhage occurs when bleeding from a damaged vessel causes blood to accumulate between the brain and the skull, in the subarachnoid space, and press on the surface of the brain instead of dispersing into the tissue. The leaked blood can irritate, damage or destroy surrounding brain cells.
Most often, a subarachnoid hemorrhage occurs because a cerebral aneurysm, an abnormal bulging outward in the wall of an artery.
There are two types of aneurysm:
Saccular :- This is the most common type. It has a neck and stem and is also known as a “berry” aneurysm because of its shape.
Saccular Aneurysm.
Fusiform :- This is a less common type of aneurysm. It is an outpouching of the wall on both sides of the artery and does not have a stem.
Fusiform Aneurysm.
Aneurysms that cause subarachnoid hemorrhage are usually located at the base of the brain in the Circle of Willis. This is an area in which a lot of blood pressure changes occur and where a lot of vessels branch off, which can expose them to weakness.
The following explains what each side of the brain does and what is affected when a stroke occurs:-
LEFT HEMISPHERE
(Stroke on left side)
Right body affected:-
- Motor speech, expressive speech, movement on right side of body, emotion control, writing, locating body in space, understanding ,math, reading numbers and letters, recognizing objects, remembering written information.
RIGHT HEMISPHERE
(Stroke on right side)
Left body affected:-
- Attention span, impulse control, movement on left side of body, initiates activities you want to do, remembering visual objects, recognition of faces, Drawing skills, awareness of the left side of the body, emotional stability, measuring distances of objects to body.
Risk Factors:-
Hypertension. -
-Smoking.
High cholesterol. -
Diabetes and poor diet.. -
-Being over overweight.
-Sedentary lifestyle.
-Excessive alcohol intake.
Symptoms:-
The symptoms of a stroke differ, depending on the part of the brain affected and the extent of the damage. Symptoms following a stroke come on suddenly and may include:
• severe headache with no known cause
• weakness, numbness, or tingling in the face, arm, or leg, especially on one side of the body
• trouble walking, dizziness, loss of balance, or coordination
• inability to speak or difficulty speaking or understanding
• trouble seeing with one or both eyes, or double vision
• confusion or personality changes
• difficulty with muscle movements, such as swallowing, moving arms and legs
• loss of bowel and bladder control
• loss of consciousness.
[right][left]
[justify][center]CVA))
Definition:-
A stroke is damage to part of the brain when its blood supply is suddenly reduced or stopped. Death of a part of the brain may lead to loss of certain body functions controlled by that affected part.
Types:-
There are two main types of stroke ischemic and hemorrhagic. Ischemic stroke is more common and occurs when blood flow to a part or parts of the brain is stopped by a blockage in a vessel. Hemorrhagic stroke is more deadly and occurs when a weakened vessel tears or ruptures, diverting blood flow from its normal course and instead leaking or spilling it into or around the brain itself.
(left) Illustration of Ischemic Stroke showing blockage of one of the brain's arteries.(right) CT scan of Hemorrhagic Stroke. Arrow points to the area of blood in the brain.
There is a third type referred to as transient ischemic attack (TIA), A TIA is caused by a brief pause in blood flow to part of the brain , the result of a temporary or partial blockage.
Ischemic stroke:-
The vast majority of strokes – approximately 83 percent — are ischemic. They are caused by an obstruction of an artery leading to or in the brain, preventing oxygenated blood from reaching parts of the brain that the artery feeds. Ischemic strokes are either thrombotic or embolic, depending on where the obstruction or clot (thrombus or embolism), causing the blockage originated:
Thrombotic Ischemic Stroke
Thrombotic stroke is caused by a thrombus (blood clot) that develops in an artery supplying blood to the brain — usually because of a repeated buildup of fatty deposits, calcium and clotting factors, such as fibrinogen and cholesterol, carried in the blood. The body perceives the buildup as an injury to the vessel wall and responds the way it would to a small wound — it forms blood clots. The blood clots get caught on the plaque on the vessel walls, eventually stopping blood flow.
There are two types of thrombotic stroke:
Large vessel thrombosis, the most common form of thrombotic stroke, occurs in the brain’s larger arteries.
In most cases, large vessel thrombosis is caused by a combination of long-term plaque buildup (atherosclerosis) followed by rapid blood clot formation. High cholesterol is a common risk factor for this type of stroke.
Small vessel disease (lacunar infarction) occurs when blood flow is blocked to a very small arterial vessel. It has been linked to high blood pressure (hypertension) and is an indicator of atherosclerotic disease.
Embolic Ischemic Stroke:-
A blood clot that forms in one area of the body and travels through the bloodstream to another where it may lodge is called an embolus. In the case of embolic stroke, the clot forms outside of the brain – usually in the heart or large arteries of the upper chest and neck – and is transported through the bloodstream to the brain. Emboli can be fat globules, air bubbles or, most commonly, bits and pieces of atherosclerotic plaque, such as lipid debris, that have detached from an artery wall. Many emboli are caused by a cardiac condition called atrial fibrillation.
Hemorrhagic stroke:-
Hemorrhagic stroke occurs when a vessel in the brain suddenly ruptures and blood begins to leak directly into brain tissue and/or into the clear cerebrospinal fluid that surrounds the brain and fills its central cavities (ventricles). The rupture can be caused by the force of high blood pressure. It can also originate from a weak spot in a blood vessel wall (a cerebral aneurysm) or other blood vessel malformation in or around the brain.
Damage can be caused in two ways. As in the case of ischemic stroke, oxygen- and nutrient-rich blood is prevented from reaching the brain cells beyond the point of rupture. In addition, leaked blood can irritate and harm the brain cells in the areas where it accumulates.
It is the location of the hemorrhage, rather than the amount of bleeding, that tends to be the bigger factor in influencing the severity of the stroke. For example, bleeds in the brainstem, though relatively tiny, can be quite lethal, whereas the same-sized bleed in the frontal lobe may not even be noticeable.
There are two types of hemorrhagic strokes. They are differentiated by where the ruptured artery is located and where the resulting blood leakage occurs.
Intracerebral Hemorrhage (ICH) or intracranial hematoma).
This type of stroke is caused by the sudden rupture of an artery or blood vessel within the brain. The blood that leaks into the brain results in a sudden increase in pressure that can damage the surrounding brain cells. If the amount of blood increases rapidly, the sudden and extreme buildup in pressure can lead to unconsciousness or death. They occur most commonly in the basal ganglia where the vessels can be particularly delicate.
High blood pressure (hypertension) is the most common cause of this type of stroke. Less common causes include trauma, infections, tumors, blood clotting deficiencies, and abnormalities in cerebral blood vessels.
Blood Vessel Abnormalities: Blood vessel abnormalities in the brain include arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs). AVMs and AVFs, also called lesions, are abnormal connections between cerebral arteries (which carry blood to the brain) and veins (which take blood away from the brain).
Subarachnoid Hemorrhage (SAH)
Subarachnoid hemorrhage occurs when bleeding from a damaged vessel causes blood to accumulate between the brain and the skull, in the subarachnoid space, and press on the surface of the brain instead of dispersing into the tissue. The leaked blood can irritate, damage or destroy surrounding brain cells.
Most often, a subarachnoid hemorrhage occurs because a cerebral aneurysm, an abnormal bulging outward in the wall of an artery.
There are two types of aneurysm:
Saccular :- This is the most common type. It has a neck and stem and is also known as a “berry” aneurysm because of its shape.
Saccular Aneurysm.
Fusiform :- This is a less common type of aneurysm. It is an outpouching of the wall on both sides of the artery and does not have a stem.
Fusiform Aneurysm.
Aneurysms that cause subarachnoid hemorrhage are usually located at the base of the brain in the Circle of Willis. This is an area in which a lot of blood pressure changes occur and where a lot of vessels branch off, which can expose them to weakness.
The following explains what each side of the brain does and what is affected when a stroke occurs:-
LEFT HEMISPHERE
(Stroke on left side)
Right body affected:-
- Motor speech, expressive speech, movement on right side of body, emotion control, writing, locating body in space, understanding ,math, reading numbers and letters, recognizing objects, remembering written information.
RIGHT HEMISPHERE
(Stroke on right side)
Left body affected:-
- Attention span, impulse control, movement on left side of body, initiates activities you want to do, remembering visual objects, recognition of faces, Drawing skills, awareness of the left side of the body, emotional stability, measuring distances of objects to body.
Risk Factors:-
Hypertension. -
-Smoking.
High cholesterol. -
Diabetes and poor diet.. -
-Being over overweight.
-Sedentary lifestyle.
-Excessive alcohol intake.
Symptoms:-
The symptoms of a stroke differ, depending on the part of the brain affected and the extent of the damage. Symptoms following a stroke come on suddenly and may include:
• severe headache with no known cause
• weakness, numbness, or tingling in the face, arm, or leg, especially on one side of the body
• trouble walking, dizziness, loss of balance, or coordination
• inability to speak or difficulty speaking or understanding
• trouble seeing with one or both eyes, or double vision
• confusion or personality changes
• difficulty with muscle movements, such as swallowing, moving arms and legs
• loss of bowel and bladder control
• loss of consciousness.
[right][left]
