Recently, an article in the New England Journal of Medicine questioned the efficacy of current treatment strategies for strokes. The impact of this is profound, as strokes are a very common and devastating medical condition. This article will discuss the causes and the presenting symptoms; then next week, I will discuss the diagnosis and management of strokes.
Strokes or Cerebral Vascular Accidents (CVA) are the number three cause of death in America, with a death rate of 150,000 Americans each year, or a death every four minutes.
Sadly, the initial presentation may be a life-threatening stroke with no obvious warning signs. In those that survive, strokes are a tremendously disabling condition, causing significant functional loss depending on the region of the brain that is affected.
Each year some 780,000 people in the United States have a stroke, roughly one stroke every 30 to 60 seconds.
A similar yet less debilitating version of a stroke is called a Transient Ischemic Attack (TIA). A TIA is defined as a sudden brain attack with complete resolution of symptoms in less than 24 hours.
The risk factors for strokes and TIA's are similar to those of cardiovascular disease.
These include: elevated cholesterol, hypertension, diabetes, advanced age, male gender, smoking and a family history of early strokes and heart attacks.
Additionally, there are some abnormalities of blood vessel structure and function that increase the risk of strokes.
Lastly, some blood clotting disorders and irregular heart beats increase the prevalence of strokes in the general population.
It is important to be vigilant for the signs of a stroke, as strokes present with highly diverse and sometimes quite subtle features. However, there are some relatively classic signs and symptoms of a stroke that all Americans should learn.
A useful pneumonic from the Minnesota Stroke Prevention Association is to act “FAST.” This pneumonic stands for F = Facial weakness, A = Arm weakness, S = Speech difficulties, and T = Time is brain tissue destruction (call 911).
The facial weakness is sudden in onset and painless, usually affecting one side of the face. This facial deficit is commonly not noticed by the patient, but is picked up by someone viewing the person's face. The facial weakness can cause an asymmetric smile, droopy eye, sagging lip, facial numbness or an inability to turn one's head.
The arm weakness is similarly painless, usually affecting one arm, but commonly an arm and leg simultaneously. This arm weakness can be as subtle as mild clumsiness or loss of finger dexterity, to complete loss of arm control with a limp, non-functional arm.
The speech difficulty can be mild, from garbled phonation and confused talk, to complete loss of speech.
Another classic sign is sudden, painless vision loss. This deficit can range from a small portion of the visual field to complete loss of vision in the affected eye. Patients classically describe this as if a “window blind” was being lowered over their eye. Another classic sign of a stroke is the sudden onset of a severe headache, out of character for the patient with no obvious trigger.
The time aspect of a stroke is centrally important, as the longer a patient waits to seek treatment for their stroke, the more permanent and irreversible the damage to the brain. In light of this, the term “time is brain” is used. Any of the above signs or unexplained changes in a person's condition absolutely warrant a call to emergency medical team or 911.
Additionally, it is critical that someone looks at a clock and documents the exact time when signs of a stroke first occur, as this directly impacts possible therapeutic options. This article cannot detail all of the possible signs of a stroke; only a medical professional and an examining physician can make the diagnosis of a stroke.
A stroke is caused by a sudden interruption of blood supply to the brain. This interruption of blood starves the brain of oxygen and nutrients. The brain is highly sensitive to such changes and immediately begins to die and undergo irreversible brain damage with a stroke. There are two major mechanisms of a stroke; either due to an obstructive blood clot (ischemic stroke) or burst blood vessel (hemorrhagic stroke).
In an ischemic stroke, a blood clot forms on a ruptured atherosclerotic plaque or a blood clot formed from a distant site travels downstream to become lodged in the arteries of the brain.
In a hemorrhagic stroke, an artery bursts and releases blood into the brain, compressing the surrounding tissue and preventing downstream blood flow to the remaining portions of the brain.
The majority of strokes are ischemic in nature and are the result of progressive atherosclerosis, or fatty plaguing of blood vessels. Another common cause of an ischemic stroke is an irregular heart beat, called atrial fibrillation. In this condition, blood pools in the top chamber of the heart, allowing small blood clots to form and are subsequently released to the brain.
Less frequently strokes are hemorrhagic, in which the blood vessels break and cause damage. The most common cause of hemorrhagic stroke is abnormal blood vessel formation, in which the vessels are weak and eventually rupture. Abnormal blood vessels are commonly due to ballooning of artery walls, forming aneurysms. A second cause is clustering of abnormally formed arteries and veins, forming AV malformations. Both aneurysms and AV malformations increase the risk of hemorrhagic strokes.
Dr. David M. Donaldson is an Auburn native and currently a
cardiologist at Massachusetts
General Hospital in Boston
Sadly, the initial presentation may be a life-threatening stroke with no obvious warning signs. In those that survive, strokes are a tremendously disabling condition, causing significant functional loss depending on the region of the brain that is affected.
Each year some 780,000 people in the United States have a stroke, roughly one stroke every 30 to 60 seconds.
A similar yet less debilitating version of a stroke is called a Transient Ischemic Attack (TIA). A TIA is defined as a sudden brain attack with complete resolution of symptoms in less than 24 hours.
The risk factors for strokes and TIA's are similar to those of cardiovascular disease.
These include: elevated cholesterol, hypertension, diabetes, advanced age, male gender, smoking and a family history of early strokes and heart attacks.
Additionally, there are some abnormalities of blood vessel structure and function that increase the risk of strokes.
Lastly, some blood clotting disorders and irregular heart beats increase the prevalence of strokes in the general population.
It is important to be vigilant for the signs of a stroke, as strokes present with highly diverse and sometimes quite subtle features. However, there are some relatively classic signs and symptoms of a stroke that all Americans should learn.
A useful pneumonic from the Minnesota Stroke Prevention Association is to act “FAST.” This pneumonic stands for F = Facial weakness, A = Arm weakness, S = Speech difficulties, and T = Time is brain tissue destruction (call 911).
The facial weakness is sudden in onset and painless, usually affecting one side of the face. This facial deficit is commonly not noticed by the patient, but is picked up by someone viewing the person's face. The facial weakness can cause an asymmetric smile, droopy eye, sagging lip, facial numbness or an inability to turn one's head.
The arm weakness is similarly painless, usually affecting one arm, but commonly an arm and leg simultaneously. This arm weakness can be as subtle as mild clumsiness or loss of finger dexterity, to complete loss of arm control with a limp, non-functional arm.
The speech difficulty can be mild, from garbled phonation and confused talk, to complete loss of speech.
Another classic sign is sudden, painless vision loss. This deficit can range from a small portion of the visual field to complete loss of vision in the affected eye. Patients classically describe this as if a “window blind” was being lowered over their eye. Another classic sign of a stroke is the sudden onset of a severe headache, out of character for the patient with no obvious trigger.
The time aspect of a stroke is centrally important, as the longer a patient waits to seek treatment for their stroke, the more permanent and irreversible the damage to the brain. In light of this, the term “time is brain” is used. Any of the above signs or unexplained changes in a person's condition absolutely warrant a call to emergency medical team or 911.
Additionally, it is critical that someone looks at a clock and documents the exact time when signs of a stroke first occur, as this directly impacts possible therapeutic options. This article cannot detail all of the possible signs of a stroke; only a medical professional and an examining physician can make the diagnosis of a stroke.
A stroke is caused by a sudden interruption of blood supply to the brain. This interruption of blood starves the brain of oxygen and nutrients. The brain is highly sensitive to such changes and immediately begins to die and undergo irreversible brain damage with a stroke. There are two major mechanisms of a stroke; either due to an obstructive blood clot (ischemic stroke) or burst blood vessel (hemorrhagic stroke).
In an ischemic stroke, a blood clot forms on a ruptured atherosclerotic plaque or a blood clot formed from a distant site travels downstream to become lodged in the arteries of the brain.
In a hemorrhagic stroke, an artery bursts and releases blood into the brain, compressing the surrounding tissue and preventing downstream blood flow to the remaining portions of the brain.
The majority of strokes are ischemic in nature and are the result of progressive atherosclerosis, or fatty plaguing of blood vessels. Another common cause of an ischemic stroke is an irregular heart beat, called atrial fibrillation. In this condition, blood pools in the top chamber of the heart, allowing small blood clots to form and are subsequently released to the brain.
Less frequently strokes are hemorrhagic, in which the blood vessels break and cause damage. The most common cause of hemorrhagic stroke is abnormal blood vessel formation, in which the vessels are weak and eventually rupture. Abnormal blood vessels are commonly due to ballooning of artery walls, forming aneurysms. A second cause is clustering of abnormally formed arteries and veins, forming AV malformations. Both aneurysms and AV malformations increase the risk of hemorrhagic strokes.
Dr. David M. Donaldson is an Auburn native and currently a
cardiologist at Massachusetts
General Hospital in Boston
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