EXAM II – STROKE QUESTIONS WITH
ANSWERS GRADED A+
STROKE - correct answer ✔✔ Stroke occurs when there is:
1. Ischemia (inadequate blood flow) to a part of the brain
2. Hemorrhage into the brain that results in death of brain cells
Functions such as movement, sensation, or emotions that were controlled by the affected area
of the brain are lost or impaired
Unlike TIA, where ischemia occurs without infarction, a stroke results in infarction and cell death
The terms BRAIN ATTACK and CEREBROVASCULAR ACCIDENT (CVA) are also used to describe
stroke
Stroke can occur at any age
About 28% occur in those younger than 65
Women are more likely than men to die from a stroke because of the greater number of women
over age 65
Of those who survive a stroke, 50-70% are functionally independent
15-30% live with permanent disability
,Common long term disabilities include:
- Hemiparesis
- Inability to walk
- Complete or partial dependence for ADLs
- Aphasia
- Depression
It's a lifelong change for patient AND family
PATHOPHYSIOLOGY OF STROKE - ANATOMY OF CEREBRAL CIRCULATION - correct answer ✔✔
Blood supplies to the brain by two major pairs of arteries
- The internal carotids (anterior circulation)
- Vertebral arteries (posterior circulation)
Carotids branch to supply most of the frontal, parietal, and temporal lobes, the basal ganglia,
and part of the diencephalon (thalamus and hypothalamus)
Major branches of the carotid arteries are:
- The middle cerebral arteries
- The anterior cerebral arteries
The vertebral arteries join to form the basilar artery, which then branches to supply the middle
and lower parts of the temporal lobes, occipital lobes, cerebellum, brainstem and part of the
diencephalon
Main branch of the basilar artery is the posterior cerebral artery
The anterior and posterior cerebral circulation is connected at the CIRCLE OF WILLIS by the
anterior and posterior communicating arteries
Genetic variations in this area are common, and all connecting vessels may not be present
,PATHOPHYSIOLOGY OF STROKE - REGULATION OF CEREBRAL BLOOD FLOW - correct answer ✔✔
Blood flow must be maintained at 750-1000 mL/min (55/mL/100 g of brain tissue) - or 20% of
the cardiac output
If blood flow to the brain is totally interrupted (e.g., cardiac arrest):
Neurologic metabolism is altered in 30 seconds
Metabolism stops in 2 minutes
Cellular death occurs in 5 minutes
CEREBRAL AUTOREGULATION normally well protects the brain from changes in mean systemic
arterial blood pressure over a range from 50-150 mm Hg
- Autoregulation involves changes in the diameter of cerebral blood vessels in response to
changes in pressure so that the blood flow to the brain stays constant
- When cerebral ischemia occurs, cerebral autoregulation may be impaired
CO2 is a potent cerebral vasodilator
- Changes in arterial carbon dioxide levels have a dramatic effect on cerebral blood flow
- Increased CO2 increases cerebral blood flow
- Decreased CO2 decreases CBF
Very low arterial oxygen levels (partial pressure of less than 50 mm Hg) or increases in hydrogen
ion concentration also increase cerebral blood flow
Factors that affect blood flow to the brain include:
- Systemic BP
- Cardiac output
, - Blood viscosity
During normal activity, oxygen requirements vary considerably, but changes in cardiac output,
vasomotor tone, and distribution of blood flow normally maintain adequate blood flow to the
head
Cardiac output has be reduced by 1/3 before CBF is reduced
Decreased viscosity increases CBF
Collateral circulation may develop over time to compensate for a decrease in cerebral blood
flow
An area of the brain can potentially receive blood supply from another blood vessel even if
blood supply from the original vessel is cut off (e.g., because of thrombosis)
In other words, the vessels in the brain make an "alternate route" for blood flow to reach
damaged areas
Individual differences in collateral circulation p
RISK FACTORS FOR STROKE - correct answer ✔✔ NON-MODIFIABLE RISK FACTORS
- Age
2/3 of strokes occur in people older than 65
Can occur at any age though
- Gender
More common in men
More women DIE from strokes than men (women tend to live longer)
ANSWERS GRADED A+
STROKE - correct answer ✔✔ Stroke occurs when there is:
1. Ischemia (inadequate blood flow) to a part of the brain
2. Hemorrhage into the brain that results in death of brain cells
Functions such as movement, sensation, or emotions that were controlled by the affected area
of the brain are lost or impaired
Unlike TIA, where ischemia occurs without infarction, a stroke results in infarction and cell death
The terms BRAIN ATTACK and CEREBROVASCULAR ACCIDENT (CVA) are also used to describe
stroke
Stroke can occur at any age
About 28% occur in those younger than 65
Women are more likely than men to die from a stroke because of the greater number of women
over age 65
Of those who survive a stroke, 50-70% are functionally independent
15-30% live with permanent disability
,Common long term disabilities include:
- Hemiparesis
- Inability to walk
- Complete or partial dependence for ADLs
- Aphasia
- Depression
It's a lifelong change for patient AND family
PATHOPHYSIOLOGY OF STROKE - ANATOMY OF CEREBRAL CIRCULATION - correct answer ✔✔
Blood supplies to the brain by two major pairs of arteries
- The internal carotids (anterior circulation)
- Vertebral arteries (posterior circulation)
Carotids branch to supply most of the frontal, parietal, and temporal lobes, the basal ganglia,
and part of the diencephalon (thalamus and hypothalamus)
Major branches of the carotid arteries are:
- The middle cerebral arteries
- The anterior cerebral arteries
The vertebral arteries join to form the basilar artery, which then branches to supply the middle
and lower parts of the temporal lobes, occipital lobes, cerebellum, brainstem and part of the
diencephalon
Main branch of the basilar artery is the posterior cerebral artery
The anterior and posterior cerebral circulation is connected at the CIRCLE OF WILLIS by the
anterior and posterior communicating arteries
Genetic variations in this area are common, and all connecting vessels may not be present
,PATHOPHYSIOLOGY OF STROKE - REGULATION OF CEREBRAL BLOOD FLOW - correct answer ✔✔
Blood flow must be maintained at 750-1000 mL/min (55/mL/100 g of brain tissue) - or 20% of
the cardiac output
If blood flow to the brain is totally interrupted (e.g., cardiac arrest):
Neurologic metabolism is altered in 30 seconds
Metabolism stops in 2 minutes
Cellular death occurs in 5 minutes
CEREBRAL AUTOREGULATION normally well protects the brain from changes in mean systemic
arterial blood pressure over a range from 50-150 mm Hg
- Autoregulation involves changes in the diameter of cerebral blood vessels in response to
changes in pressure so that the blood flow to the brain stays constant
- When cerebral ischemia occurs, cerebral autoregulation may be impaired
CO2 is a potent cerebral vasodilator
- Changes in arterial carbon dioxide levels have a dramatic effect on cerebral blood flow
- Increased CO2 increases cerebral blood flow
- Decreased CO2 decreases CBF
Very low arterial oxygen levels (partial pressure of less than 50 mm Hg) or increases in hydrogen
ion concentration also increase cerebral blood flow
Factors that affect blood flow to the brain include:
- Systemic BP
- Cardiac output
, - Blood viscosity
During normal activity, oxygen requirements vary considerably, but changes in cardiac output,
vasomotor tone, and distribution of blood flow normally maintain adequate blood flow to the
head
Cardiac output has be reduced by 1/3 before CBF is reduced
Decreased viscosity increases CBF
Collateral circulation may develop over time to compensate for a decrease in cerebral blood
flow
An area of the brain can potentially receive blood supply from another blood vessel even if
blood supply from the original vessel is cut off (e.g., because of thrombosis)
In other words, the vessels in the brain make an "alternate route" for blood flow to reach
damaged areas
Individual differences in collateral circulation p
RISK FACTORS FOR STROKE - correct answer ✔✔ NON-MODIFIABLE RISK FACTORS
- Age
2/3 of strokes occur in people older than 65
Can occur at any age though
- Gender
More common in men
More women DIE from strokes than men (women tend to live longer)
