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.