Chapter 62
Stroke
KEY POINTS
PATHOPHYSIOLOGY OF STROKE
• The brain needs a continuous supply of blood to provide the oxygen and glucose that
neurons need to function. A stroke occurs when there is an interruption, either from
ischemia to a part of the brain or hemorrhage into the brain, in the blood supply that
results in the death of brain cells.
• Two major pairs of arteries supply blood to the brain: internal carotid arteries (anterior
circulation) and vertebral arteries (posterior circulation). Factors that affect blood flow to
the brain include systemic BP, cardiac output, and blood viscosity.
• Atherosclerosis, a hardening and thickening of arteries, is the major cause of ischemic
stroke. It can lead to thrombus formation and contribute to emboli.
RISK FACTORS FOR STROKE
• The most effective way to decrease the burden of stroke is prevention. Nonmodifiable
risk factors include age, gender, race, and heredity.
• Hypertension is the single most important modifiable risk factor. Other risk factors
include increased serum cholesterol, smoking, excess alcohol consumption, obesity,
physical inactivity, poor diet, cardiac abnormalities, and drug use.
1
Copyright © 2023 by Elsevier, Inc. All rights reserved.
, TYPES OF STROKE
Ischemic Stroke
• A transient ischemic attack (TIA) is a transient episode of neurologic dysfunction caused
by focal brain, spinal cord, or retinal ischemia, but without acute infarction of the brain.
Symptoms typically last less than 1 hour. Although most TIAs resolve, one third will
progress to an ischemic stroke.
• An ischemic stroke results from inadequate blood flow to the brain from partial or
complete occlusion of an artery. They are divided into thrombotic and embolic strokes.
• A thrombotic stroke occurs from injury to a blood vessel wall and formation of a blood
clot. The lumen of the blood vessel becomes narrowed, and if it becomes occluded,
infarction occurs.
• The extent of a thrombotic stroke depends on rapidity of onset, size of the lesion, and
presence of collateral circulation.
• Embolic stroke occurs when an embolus lodges in and occludes a cerebral artery,
resulting in infarction and edema of the area supplied by the involved vessel. The patient
often has a rapid occurrence of severe symptoms. Prognosis is related to the amount of
brain tissue deprived of its blood supply.
Hemorrhagic Stroke
• Hemorrhagic strokes result from bleeding into the brain tissue itself or into the
subarachnoid space or ventricles.
2
Copyright © 2023 by Elsevier, Inc. All rights reserved.
Stroke
KEY POINTS
PATHOPHYSIOLOGY OF STROKE
• The brain needs a continuous supply of blood to provide the oxygen and glucose that
neurons need to function. A stroke occurs when there is an interruption, either from
ischemia to a part of the brain or hemorrhage into the brain, in the blood supply that
results in the death of brain cells.
• Two major pairs of arteries supply blood to the brain: internal carotid arteries (anterior
circulation) and vertebral arteries (posterior circulation). Factors that affect blood flow to
the brain include systemic BP, cardiac output, and blood viscosity.
• Atherosclerosis, a hardening and thickening of arteries, is the major cause of ischemic
stroke. It can lead to thrombus formation and contribute to emboli.
RISK FACTORS FOR STROKE
• The most effective way to decrease the burden of stroke is prevention. Nonmodifiable
risk factors include age, gender, race, and heredity.
• Hypertension is the single most important modifiable risk factor. Other risk factors
include increased serum cholesterol, smoking, excess alcohol consumption, obesity,
physical inactivity, poor diet, cardiac abnormalities, and drug use.
1
Copyright © 2023 by Elsevier, Inc. All rights reserved.
, TYPES OF STROKE
Ischemic Stroke
• A transient ischemic attack (TIA) is a transient episode of neurologic dysfunction caused
by focal brain, spinal cord, or retinal ischemia, but without acute infarction of the brain.
Symptoms typically last less than 1 hour. Although most TIAs resolve, one third will
progress to an ischemic stroke.
• An ischemic stroke results from inadequate blood flow to the brain from partial or
complete occlusion of an artery. They are divided into thrombotic and embolic strokes.
• A thrombotic stroke occurs from injury to a blood vessel wall and formation of a blood
clot. The lumen of the blood vessel becomes narrowed, and if it becomes occluded,
infarction occurs.
• The extent of a thrombotic stroke depends on rapidity of onset, size of the lesion, and
presence of collateral circulation.
• Embolic stroke occurs when an embolus lodges in and occludes a cerebral artery,
resulting in infarction and edema of the area supplied by the involved vessel. The patient
often has a rapid occurrence of severe symptoms. Prognosis is related to the amount of
brain tissue deprived of its blood supply.
Hemorrhagic Stroke
• Hemorrhagic strokes result from bleeding into the brain tissue itself or into the
subarachnoid space or ventricles.
2
Copyright © 2023 by Elsevier, Inc. All rights reserved.
