Stroke Flashcards
Types of Hemorrhage
- epidural (lemon)
- subdural (banana)
- subarachnoid (spider legs)
- intraparenchymal/intracerebral (inside brain)
Intracerebral Hemorrhage Morbidity/Mortality
- Same as intraparenchymal hemorrhage
- high morbidity and mortality
- no medical or surgical tx of proven benefit in improving mortality or functional outcome
Intracerebral Hemorrhage Clinical Presentation
- acute focal neurologic deficit
- dec. LOC
- vomiting
- headache
Deep Intracerebral Hemorrhage (ICH)
- common locations
- common risk factors
- outcome
- located where small perforating arteries are: basal ganglia, thalamus, pons, cerebrum
- common risk factors: HTN, age
- poor outcome: none white higher risk
Lobar Intracerebral Hemorrhage
- location
- risk factors
- outcome
- location: frontal > parietal > occipital > temporal
- risk factors: age, dementia, coagulopathy, HTN, amyloid angiopathy
- outcome: well tolerated, white & asian at higher risk
Subarachnoid Hemorrhage
- cause
- definition
- hemorrhage into space between arachnoid mater and brain
- most common cause: traums
- non traumatic causes: aneurysm, arteriovenous malformation, unknown
What is an aneurysm?
-weak bulging spot on wall of brain artery
Which aneurysms are at greatest risk of rupture?
-large, poster (P-com) aneurysms are at greatest risk of rupture
Aneurysmal Subarachnoid Hemorrhage
- clinical presentation
- outcome
Clinical Presentation
- sudden severe headache
- sometimes focal deficit
- altered LOC
- sudden death about 1/3 cases
- sympathetic surge
- cardiac arrhythmia
- hydrocephalus
Outcomes:
- 50-60% mortality
- 15-20% moderate disability
- 15-20% prior level of functioning
Hunt and Hess Classification of Subarachnoid Hemorrhage
- grade 1 is best outcome
- grade 5 is worst outcome
Subarachnoid Hemorrhage Risk Factors
- smoking
- women>men
- family hx
- other medical conditions: polycystic kidney disease, ehlers-danlos, marfan
- HTN may be risk factor for aneurysm formation but not rupture
Aneurysm Tx Options
- clipping- craniotomy
- coiling
- pipeline- novel technique
Subarachnoid Hemorrhage Complications
- rebleed
- hydrocephalus
- vasospasm (4-14 days) (risk of ischemic stroke)
- cerebral salt wasting
Arteriovenous Malformation
- abnormal connection between artery and vein without capillary risk
- thought to be congenital
- presentation: hemorrhage, incidental, seizure
- inc. risk for hemorrhage
Ischemic Stroke Definition
-fixed focal neurological deficit lasting > 24 hrs w/ evidence of acute infarction
Transient Ischemic Attack Definition
-brief episode of neurological dysfunction
Lipohyalinosis
-small vessel disease of the brain
Causes of Stroke in Young Patients
- hematological causes
- malignancies
- oral contraceptives
- post partum
- anti-phospholipid antibody syndrome
Treatment of Ischemic Stroke
- anti-platelet drugs (ASA, clopidogrel)
- anticoagulants (warfarin)
Carotid Edarterectomy
- successful surgery reduces risk of stroke and TIA
- short term risks of procedure vs. long term benefit of surgery
Tissue Plasminogen Activator (TPA)
- used in acute stroke setting up to three or 4.5 hours later
- earlier intervention greater benefit
Berry Aneurysm
- result of vessel weakening
- commonly between ant. cerebral and ant. communicating arteries
- occur at bifurcations
Areas Perfused by Middle Cerebral Artery
- speech
- sensory
- motor
Areas Perfused by Middle Cerebral Artery
-medial aspect of brain
Areas Perfused by Posterior Cerebral Artery
- visual cortex
- some hippocampus
Etiology of Ischemic Stroke
- artery to artery (carotid, vertebral, aortic arch, intracranial stenosis)
- cardiac source (A fib, dilated cardiomyopathy, endocarditis/valvular diseases)
Penumbra
-brain at risk during stroke
Imaging Modalities That Provide Good Anatomic Definition of Cerebrovasculature and Lesion
- MRA (Magnetic Resonance Angiography)
- CTA (CT Angiography) (more sensitive)
Imaging Modalities That Distinguish Between Penumbra and Dead Tissue
- MR
- CT perfusion (more sensitive)
Stroke Imaging Protocol
- Noncontrast head CT
- perfusion CT
- CT angiogram of head and neck
Non-contrast Brain CT Contraindications
-look for contraindication for antithrombolytic therapy (hematoma, hemorrhage, neoplasm, large infarct)
Perfusion CT
- intravenous contrast bolus determines amount of blood flow, blood volume, and timing
- inc. time to start, inc. time to peak, dec. blood volume = completed infarct
- inc. time to start, inc. time to peak, normal or inc. blood volume = brain at risk
- high radiation dose
- continuous imaging at 2-4 locations
CT Angiogram
-use intravenous contrast bolus and thin sections moving through anatomy to depict vascular anatomy
Timeline for CT of Infarcts
- 1-6 hrs: loss of grey matter density
- 6 hrs - 4 days: progressive swelling and hypodensity
- 4 days-14days: return towards normal density and volume
- > 14 days: varying degree of hypodensity and volume loss
Timeline for MR Imaging of Infarcts
- 1 hr- 10days: bright on diffusion weighted imaging
- swelling and inc. signal on FLAIR and T2 weighted scans follows same pattern as swelling and low density on CT
- Diffusion weighted imaging (DWI) great for small infarcts and telling new from old
Intracranial Embolectomy
- MERCI device
- Penumbra devise
