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CVACVAIschemic and HemorrhagicIschemic and Hemorrhagic
PathophysiologyPathophysiologyStroke is a rapid development of focal neurologic deficit caused by a disruption of blood supply to the corresponding area of the brain.
To be classified as a stroke the neurological deficits need to persist for at least 24 hours
A stroke is termed a transient ischemic attack (TIA) if less than 24 hours
TIA risk factor
A variety of focal deficits are possible
changes in consciousness
sensory, motor, language, cognitive, and perceptual impairments
motor deficits are characterized by paralysis (hemiplegia) or weakness (hemiparesis) typically on the side opposite of the lesion
PathophysiologyPathophysiologyHemorrhagic
Rupture of a blood vessel with abnormal bleeding into extravascular area of brain
usually the result of rupture of cerebral vessel or trauma
Primary cerebral hemorrhage (non-traumatic spontaneous hemorrhage) usually occur in small blood vessels weakened by atherosclerosis which produces an aneurysm
Subarachnoid hemorrhage occurring from bleeding into the subarachnoid space typically from a saccular or berry aneurysm affecting large blood vessels.
Can be intracerebral which is bleeding within the brain or subarachnoid
PathophysiologyPathophysiologyIschemic
Occlusion of a blood vessel from thrombus, embolism, or conditions that produce low systemic perfusion pressure
Cerebral thrombosis is a formation or developing clot within the cerebral arteries or their branches.
Thrombi can lead to ischemia or occlusion of an artery which could result in a cerebral infarctions or tissue death (atherothrombotic brain infarction [ABI])
subtypes include
large artery, atherosclerosis, cardiogenic embolism, small vessel occlusive disease
Risk FactorsRisk FactorsMajor risk factors
heart disease
hypertension
diabetes
Risk factors such as diabetes mellitus, hyperlipidemia, cigarette smoking, and hypertension fail to distinguish between ischemic and hemorrhagic types of stroke.
Having a TIA is a risk factor for stroke with about 10% of people having a major stroke within 90 days
Specific Risk FactorsSpecific Risk FactorsIschemic stroke
Age: elderly over 80
Race: from greatest to least risk
black > hispanic > white
Sex: More men than women except in the 35-44 age range
Family History: monozygotic twins
Hemorrhagic stroke
Age: elderly
Sex: no significant difference between men and women except during pregnancy and postpartum
Race/Ethnicity: Asians > African Americans > Hispanics/Native Americans > Whites
Genetics: Icelandic CAA and Dutch CCA
Early Warning Signs of StrokeEarly Warning Signs of StrokeSudden numbness or weakness of the face, arm, or leg especially on one side of the body
Sudden confusion, trouble speaking or understanding
Sudden trouble seeing in one or both eyes
Sudden trouble walking, dizziness, loss or balance or coordination
Sudden severe headaches with no know cause
Sudden nausea, fever or vomiting distinguished from a viral by the speed of onset (minutes or hours vs several days)
Brief loss of consciousness or a period of decreased consciousness (fainting, confusion, convulsions, or coma)
Signs and SymptomsSigns and SymptomsClinical features of a hemorrhagic stroke include:
severe headache from increased intracranial pressure
progressive deterioration from continued bleeding
vomiting from increased intracranial pressure
neck stiffness from meningeal irritation
bilateral babinski signs from enlargement of hemorrhage beyond the blood vessel involved
coma from bilateral cerebral dysfunction or uncal herniation
greater arm and leg hemiparesis
Signs and SymptomsSigns and SymptomsCommon presentation of a patient with ischemic type of stroke:
previous TIA
numbness and uncoordinated extremity movements
alert mental status but may struggle with generating words
mild hemiparesis
facial paralysis
mild headache
absence of severe hypertension
absence of Babinski sign
Positive for dorsiflexion of the great toe with fanning of the other toes on stimulation of the lateral plantar surface of the foot
How is the Patient Affected?How is the Patient Affected?
BOTH ischemic and hemorrhagic types of stroke may cause neurological deficits such as hemiparesis, hemisensory loss, aphasia, opthalmoplegia and visual field cuts
Hemorrhagic stroke may cause additional symptoms due to leakage of blood that displaces and compressing surrounding brain tissues
Special TestsSpecial TestsA TIA is a predictor of ischemic type stroke
The greatest risk of stroke is within 90 days after the TIA with half occurring within first 7 days.
All patients with a new stroke need to undergo a CT to distinguish between hemorrhagic and ischemic stroke
Babinki Test for ischemic or hemorrhagic
No findings or combination of findings suggest are definitive of either type of stroke
To rule in/out either type of stroke requires neuroimaging to be absolutely certain
ReferencesReferencesGrysiewicz, Rebbeca A. et al. Epidemiology of Ischemic and Hemorrhagic Stroke: Incidence, Prevalence, Mortality, and Risk Factors. Neuro Clin (2008); 26: 871-895.
Khaw, Kay-Tee. Epidemiology of Stroke. Journal of Neurology, Neurosurgery and Psychiatry (1996); 61: 333-338.
Runchey, Shauna and McGee, Steven. Does This Patient Have Hemorrhagic Stroke? Clinical Findings Distinguishing Hemorrhagic Stroke from Ischemic Stroke. JAMA (2010); 303; 2280-2286.