B7.059 Stroke Flashcards
incidence of stroke in the US
1 mil new cases yearly #3 cause of death 6 mil stroke survivors at high risk of recurrence
what is a stroke
sudden onset of focal brain deficits
usually from blockage or rupture of a cerebral blood vessel
3 common causes of ischemic stroke
atherosclerosis (large vessels)
cardiogenic
small vessel disease (lacunes)
types of strokes caused by atherosclerosis
artery to artery emboli
stenosis (less common)
primary cause of cardiogenic emboli
a-fib
small vessel disease processes
lipohyalinosis
microatheroma
toast classification of stroke causes
85% infarction: -20% cardiogenic -25% atherosclerotic -20% lacunes -30% cryptogenic -5% unusual 15% hemorrhage: -intracerebral -subarachnoid
mechanism of cardiogenic emboli
emboli from heart become lodged in cerebral blood vessels
typically red clot
diagnosis of cardiogenic stroke
identify source
- continuous EKG (look for a-fib)
- trans thoracic echo
- trans esophageal echo
common sources of cardiogenic embolism
nonvalvular a-fib- 45% acute MI- 15% prosthetic valves- 10% rheumatic heart disease- 10% ventricular aneurysm- 10% uncommon source- 10%
treatment of cardiogenic ischemic strokes
aimed at prevention of future strokes
- anticoagulation
- watchman device
- exception: endocarditis, treat underlying cause w antibiotics (infective) or immunosuppressive agents (marantic)
anticoagulation options for cardiogenic strokes
warfarin (INR 2-3 for a-fib) monoclonal Abs -apixaban -edoxaban -dabigatran -rivaroxaban
anticoagulation therapy in stroke prevention in a-fib
very effective
warfarin: 65% risk reduction
dabigatran: 75% risk reduction
why choose dabigatran over warfarin?
easier
decreased risk of intracranial hemorrhage
diagnosis of an atherosclerotic stroke
large vessel stroke plus:
1. evidence of atherosclerosis on imaging
OR
2. risk factors for atherosclerosis
imaging for atherosclerosis
carotid duplex
CT angio
MR angio
catheter angio
risk factors for atherosclerosis
in order of importance:
- age
- HTN
- smoking
- DM
- hyperlipidemia
secondary prevention for atherosclerotic stroke
risk factor control
antithrombotic (usually antiplatelet)
carotid artery stenting or endarterectomy
speak to risk factor control for prevention of atherosclerotic stroke
most important are HTN and smoking
improvement of DM control does not decrease stroke risk, but is worthwhile for other causes
hyperlipidemia control more important for coronary artery disease
lipids and stroke prevention
hyperlipidemia not well established risk factor
stroke risk decreased in patients with diabetes, CHD, and PVD treated with statins
effect of DM on stroke risk
increases stroke risk 2-4x
synergistic with other risk factors (HTN, hyperlipids)
tight glucose control doesn’t have proven benefit for stroke
antithrombotic agents for atherosclerotic stroke
- aspirin
- clopidogrel
- dipyridamole
- DO NOT use warfarin, similar effectiveness to aspirin with much higher bleeding risk
- aspirin typically used
does intracranial artery stenting work?
no, more damage than benefit
can dislodge additional emboli during procedure which can cause new strokes
when should carotid endarterectomy. stenting be considered
symptomatic, high grade stenosis
risk of perioperative MI and stroke too high to justify surgery in most asymptomatic patients and patients with moderate stenosis
mechanism of lacunar strokes
penetrating artery occlusion via lipohyalinosis or microatheroma
lipohyalinosis
HTN and DM causes necrosis and hyalinization of small vessels that can lead to occlusion
risk factors for small vessel disease
age HTN DM hyperlipidemia smoking
diagnosis of lacunar infarcts
clinical syndrome: will see subcortical signs without cortical findings
MRI confirmation (misses 25%)
risk factors: HTN, DM
pure motor hemiparesis lacunar syndrome
localization to the posterior limb of the internal capsule, basilar pons
ataxia-hemiparesis lacunar syndrome
localization to the internal capsule, basilar pons
dysarthria-clumsy hand lacunar syndrome
localization to the anterior limb of the internal capsule, basilar pons
pure sensory lacunar syndrome
localization to the thalamus
prevention of recurrence of lacunar strokes
poorly studied
risk factor control: HTN. DM
antiplatelets assumed to be effective
NO operative intervention
unusual causes of stroke
arterial dissection (spontaneous, traumatic) drugs of abuse (coke, meth)
potential cryptogenic causes of stroke
hypercoagulable states
patent foramen ovale
monitor long term for a-fib
why might patent foramen ovale cause stroke
fibrous adhesions fail to seal the atrial septum after birth (occurs in 25% of people)
persistence of a potential shunt between the R and L atria
paradoxical emboli
acute treatment of ischemic stroke
IV alteplase (TPA)
catheter thrombectomy
must have excellent multidisciplinary system of care in place
IV alteplase (TPA)
up to 4.5 hours after onset
effect for all ischemic stroke subtypes
intracerebral hemorrhage
NNT8
catheter thrombectomy
up to 24 hr after onset
only effective in proximal large vessel occlusion
intracerebral hemorrhage
NNT 2
2 types of spontaneous intracranial hemorrhage and their causes
- intracerebral
- hypertensive
- amyloid angiopathy
- coagulopathy - subarachnoid
- ruptured berry aneurysm
- thunderclap headache
locations of intracerebral hemorrhage by subtype
hypertensive: subcortical
-thalamus
-cerebellum
-pons
-BG
amyloid angiopathy: lobar
2 types of vascular dementia
- history of clinical strokes correlated with onset of cognitive deficits
- no history of clinical strokes by diffuse subcortical vascular disease on imaging
* * both have a subcortical dementia pattern aka abnormal elementary neuro exam
