Path - Cerebrovascular Disease Flashcards
what are the symptomatic effects of an anterior cerebral artery ACA) infarction
upper motor neuron-type weakness and cortical-type sensory loss
contralateral leg is affected more than the arm or face
“alien hand” syndrome (semiautomatic movements of the contralateral arm are not under voluntary control)
what are the symptomatic effects of a posterior cerebral artery (PCA) infarct
contralateral homonymous hemianopia
loss of half vision in both eyes on the contralateral half
what are the symptomatic effects of a middle cerebral artery (MCA) infarct
1) aphasia
2) hemineglect (patients fail to be aware of items to one side of space)
3) hemianopia
4) face-arm or face-arm-leg sensorimotor loss
5) gaze preference is toward the side of the lesion
what are causes of global ischemia
cardiac arrest, shock, severe hypotension
what are causes of focal ischemia
1) embolic or thrombotic arterial occlusion
2) atherosclerosis in HTN
damage to a watershed area produces what kind of necrosis
sickle-shaped band of necrosis
infarction in the ACA-MCA watershed area produces what sx
proximal arm and leg weakness
transcortical aphasia (language issues)
infarction in the MCA-PCA watershed area produces what sx
higher-order visual processing deficits
how do ACA-MCA watershed area infarcts occur
occlusion of the internal carotid a.
hypotension in a pt with carotid stenosis
what is the main cause of stenosis of the internal carotid a.
atherosclerosis
sx of carotid stenosis
1) contralateral face-arm or farm-arm-leg weakness
2) contralateral sensory changes
3) contralateral visual field defects
4) aphasia or neglect
thrombi formed in the internal carotid a. can embolize where?
MCA, ACA, ophthalmic artery
what are the primary sites of thrombosis
1) carotid bifurcation
2) origin of MCA
3) either end of basilar a.
describe how atherosclerosis can cause thrombosis
atheroma (intimal lesion, lipid core covered by fibrous cap) –> ruptures –> exposes blood to thrombogenic substance –> thrombosis/clot
rupture of an atherosclerotic plaque resulting in thrombosis causes what kind of infarct
wedge-shaped
describe paradoxical embolus and what can cause it
thromboembolus formed in the venous system travels to the arterial system
- patent foramen ovale (PFO)
describe causes of:
- air emboli
- septic emboli
- fat or cholesterols emboli
- merantic emboli
- amniotic fluid emboli
- air emboli: deep sea divers
- septic emboli: bacterial endocarditis
- fat or cholesterols emboli: trauma to long bones
- merantic emboli: noninfectious endocarditis (NBTE)
- amniotic fluid emboli: childbirth
list causes of hyper coagulable states that can cause thrombosis
1) heritable (protein S and C deficiency, antithrombin III deficiency)
2) dehydration
3) adenocarcioma/malignancies
4) surgery, trauma, childbirth
5) DIC
6) hematologic disorder (sickle cell, leukemia, polycythemia)
7) vasculitis
causes of TIAs
- migraines
- seizures
- cardiac arrhythmias
- hypoglycemia in elderly
what is the duration of TIAs
how do different durations cause different brain deficits
less than 24 hours
- typically ~10 mins tho
> 10 mins: some permanent cell death
> 1 hour: usually small infarcts, complete functional recovery can occur within 1 day
what are the potential mechanisms behind a TIA
1) an embolus temporarily occludes, then dissolves
2) in situ thrombus formation
3) vasospasm
compare the two types of stroke
1) hemorrhagic (red): emboli associated
2) ischemic (pale): thrombus associated
compare thrombus and emboli
thrombus: blood clot that forms in a vein
emboli: anything that travels through the blood vessels until it reaches a vessel that is too small to let it pass
what event can occur with an ischemic stroke causing more severe consequences
hemorrhagic conversion
- fragile vessels rupture leading to secondary hemorrhage