ischemia stroke / TIA Flashcards
(61 cards)
What percentage of all strokes are ischemic strokes?
80-85%
Ischemic strokes are the most common type of stroke.
What is the primary mechanism leading to ischemic stroke?
Blood vessel obstruction
This leads to an ischemic core surrounded by an ischemic penumbra.
What is the ischemic penumbra?
Area of potentially salvageable tissue with reduced blood flow
Can be recovered if reperfusion occurs rapidly (3-4 hours).
What are the main causes of ischemic stroke?
Thromboembolism, hypercoagulable state, hypoperfusion, unusual causes
Includes thrombosis at atheromatous plaque, cardiac sources, and conditions like aortic dissection.
What is thromboembolism?
Thrombosis and embolism
Thrombosis occurs at atheromatous plaque, while embolism can arise from distant plaques or cardiac sources.
What are common cardiac sources of embolism?
Mural thrombus after MI, A. Fib, MS, dilated cardiomyopathy, patent foramen ovale, endocarditis, prosthetic valve
These conditions increase the risk of embolic strokes.
What is the most important modifiable risk factor for ischemic stroke?
Hypertension
It is considered the #1 risk factor.
List non-modifiable risk factors for ischemic stroke.
- Age
- Family history
- Race (African American)
- Gender (estrogen protective in premenopausal females)
These factors cannot be changed.
What are some modifiable risk factors for ischemic stroke?
- Previous stroke/Transient Ischemic Attack
- Heart disease (A. fib → embolism)
- Hyperlipidemia
- Smoking
- Alcohol
- Cocaine & amphetamine abuse
- Hypercoagulability
- Polycythemia
- Sickle cell disease
Lifestyle changes can impact these factors.
What are the common symptoms of ischemic stroke?
Negative symptoms (loss of function)
Symptoms depend on the territory affected.
What area is the commonest site for embolism in ischemic stroke?
Middle cerebral artery
Symptoms include face & arm weakness greater than leg weakness.
What symptoms are associated with middle cerebral artery strokes?
- Contralateral homonymous hemianopia with ipsilateral gaze deviation
- Aphasia (if dominant hemisphere affected)
- Apraxia, agraphia, neglect, agraphesthesia, astereognosia (if non-dominant)
These symptoms vary with the hemisphere affected.
What symptoms are associated with anterior cerebral artery strokes?
- Leg weakness > arm weakness
- Cognitive or personality changes
- Abulia if bilateral
- Apraxia
This territory is less commonly affected than the middle cerebral artery.
What symptoms are associated with posterior cerebral artery strokes?
- Contralateral homonymous hemianopia with macular sparing
- Visual agnosia
Affects the visual processing areas of the brain.
What are the symptoms of posterior circulation strokes?
- Diplopia
- Vertigo
- Dizziness
- Ataxia
- Dysarthria
- Dysphagia
These symptoms indicate involvement of the brainstem and cerebellum.
give examples for the causes of ischemic stroke
hypercoagulable state: antiphospholipid syndrome
hypoperfusion: watershed infarction
others: aortic dissection, vasculitis, drug abuse
What is an ischemic stroke?
A type of stroke caused by a blockage of blood flow to the brain.
What are the complications of ischemic stroke?
Cerebral edema, hemorrhage into the infarction, seizures.
What are lacunar infarcts?
Small, deep infarcts caused by occlusion of penetrating brain arteries in deeper brain structures.
Which brain structures are affected by lacunar infarcts?
Basal ganglia, internal capsule, thalamus, pons.
What characterizes pure motor lacunar infarcts? And where’s the lesion located?
Weakness on one side without sensory or cortical involvement.
Posterior limb of internal capsule
What characterizes pure sensory lacunar infarcts? And where’s the lesion located?
Numbness without weakness or cortical involvement.
VPL nucleus of thalamus.
What is ataxic hemiparesis?
Ipsilateral weakness and limb ataxia out of proportion to motor deficit.
What additional symptoms may accompany ataxic hemiparesis?
Dysarthria, nystagmus, gait deviation towards.