Stroke syndromes Flashcards
What is an embolic stroke?
Masses formed elsewhere in the circulatory system travel through the bloodstream to block brain vessels of smaller diameter than the embolus
What is a thrombotic stroke?
Buildup of atherosclerotic plaques within vessel walls, resulting in gradual vessel occlusion
What is tissue plasminogen activator (tPA)?
Breaks up closse
Effectiveness significantly diminished >3 hours after infarct
What is an intracerebral hemorrhage?
Internal bleeding in the brain
can cause stroke
What are the most immediate pathogenic events in focal cerebral ischemia?
Anoxic depolarization
Excitotoxicity
What is a focal stroke characterized by?
Gradient of metabolic stress radiating from the core
Depolarizations become shorter-lasting as you move away from the core
How is the ischemic core defined?
Spread of anoxic depolarization
Peri-infarct depolarizations recover and recur in penumbra area surrounding ischemic core
What options must be considered when imaging a stroke?
Non-contrast CT - must be performed to rule out hemorrhage prior to tPA admin.
CT - widely available, rapid results
Diffusion-weighted MRI scans - much more accurate, but availability/cost must be considered
What is the penumbra?
Area immediately surrounding the dead core that is potentially salvageable with intervention
What is a lacunar infarct?
Small infacted area (end artery occlusion)
What is a watershed infarct?
Occlusion between 2 major artery distributions
E.g. MCA/PCA border
What is a transient ischemic attack?
Acute episode typically resolved within 30 minutes
Critically important to recognize diagnose, and treat
Highly predictive of a major stroke
What is amaurosis fugax?
Transient, unilateral loss of vision resulting from occlusion of the central retinal artery
What symptoms result from cortical strokes (i.e. large vessel strokes)?
Contralateral spastic limb and lower face paralysis with babinski
Contralateral fine touch and proioception loss
Ipsilateral vision loss
Aphasia if in dominant hemisphere
Describe middle cerebral artery strokes.
Three regions: Superior, inferior, deep
Primarily upper signs
Dominant hemisphere - global aphasia
Tongue deviation away from the side of the lesion
What is a stem infarct?
Proximal MCA occlusion covering all three regions; often present with gaze preference toward the side of the lesion
Describe anterior cerebral artery strokes
Primarily lower signs that present as UMN weakness
Medial frontal lobe effects - abulia, akinetic mutism, urinary incontinence
Describe posterior cerebral artery strokes
Contralateral homonymous hemianopsia
Memor deficits
Alexia without agraphia
Describe subcortical strokes
Small vessel strokes
Smaller, more limited territories supplying deep white matter
Present similarly to cortical strokes, except for a lack of cortical signs
Lenticulostriate arteries supply genu and posterior limb of the IC
Describe thalamic strokes
PCA, P. Comm., Ant. Choroidal
Wide range of symptoms
Contralateral homonymous hemianopsia - involving LGN
Thalamic syndrome - Extreme contralateral pain
What differentiates brainstem from cortical strokes?
Brainstem presents with ipsilateral numbness instead of contralateral
What is Weber’s syndrome?
Stroke involving penetrating branches of the PCA
Contralateral paresis/paralysis below neck
Ipsilateral oculomotor ophthalmoplegia
What is Claude’s syndrome?
PCA/basilar artery stroke
Contralateral upper limb tremor, ipsilateral oculomotor ophthalmoplegia
What is Benedikt’s syndrome?
Penetrating branches of the basilar artery
Combination of Weber’s and Claude’s
