vascular brain events Flashcards
most common site of berry aneurysm
anterior communicating artery (occurs at bifurcations)
rupture of berry aneurysm classically causes
subarachnoid hemorrhage: “worst headache of life”,
blood in CSF irritates brain → headache
other consequences: hemorrhagic stroke, compression of optic chiasm
conditions associated with berry aneurysm
ADPKD - cysts in kidneys + berry aneurysms Ehlers-Danlos advanced age hypertension smoking african american
lenticulostriate arteries supply the basal ganglia and thalamus and are at risk for
charcot-bouchard microaneurysms if chronic HTN
non-traumatic causes of subarachnoid hemorrhage
rupture of berry aneurysm (EDS, ADPKD, HTN, age) or
AVM
most common cause of subarachnoid hemorrhage overall
trauma
what is normally present in subarachnoid space
CSF
how to diagnose subarachnoid hemorrhage
1) CT scan of brain - look for blood
2) lumbar puncture (even if negative CT) - look for blood in 3rd/4th tube or xanthochromia (waited to go to ER, Hb has broken down to bilirubin → yellow CSF)
treatment of subarachnoid hemorrhage
surgical clip
nimodipine (dihydropyridine CCB, -dipine): dilates arteries - doesn’t prevent vasospasm that can occur 2-3 days after but improves outcomes
where to enter for lumbar puncture
L3-L5: keeps spinal cord alive!
spinal cord ends between L1-L2
L4 = iliac crest
layers of tissue before entering subarachnoid space
skin
superficial fascia
3 ligaments: supraspinous ligament, interspinous ligament, ligamentum flavum
epidural space: epidural roots (lumbar, local anesthetic works here)
dura mater
subdural space
arachnoid membrane
subarachnoid space: CSF (spinal anesthetic, more potent, C-section)
rupture of middle meningeal artery (br. of maxillary a.) secondary to temporal bone fracture will cause
epidural hematoma
high pressure artery - rapid expansion
what causes this course:
head injury → LOC → LUCID interval →hrs later: uncal herniation → CN3 palsy (down + out, blown pupil), headache, vomit, seizure, death
epidural hematoma
epidural hematoma on CT
Epidural = Eye (lens, biconvex)
can’t go past suture lines
rupture of bridging veins seen in elderly fall (esp if on warfarin), alcoholic fall, whiplash, shaken baby syndrome causes
subdural hematoma
slow venous bleed
subdural hematoma on CT
Subdural = CreScent
causes of interparenchymal hemorrhage
anything that can rupture cerebral blood vessels: severe systemic hypertension (consider this when hypertensive emergency) amyloid angiopathy vascular malformations vasculitis neoplasm growing in vessel wall anti-coagulant therapy cocaine - ↑bp
most susceptible vessels that will rupture and cause intraparenchymal hemorrhage
lenticulostriate vessels supplying basal ganglia + internal capsule
charcot-bouchard aneurysm of these vessels → rupture → hemorrhage
newborns at risk for intraventricular hemorrhage in the newborn
premature
cause of intraventricular hemorrhage in the newborn
germinal matrix in subependymal, subventricular zone that gives rise to neurons and glia in development
if considering a stroke in a patient first step in management:
order CT scan w/o contrast
if acute bleed (white): consider hemorrhagic stroke
otherwise consider ischemic stroke
causes of interparenchymal hemorrhage
anything that can rupture cerebral blood vessels: severe systemic hypertension (consider this when hypertensive emergency) amyloid angiopathy vascular malformations vasculitis neoplasm growing in vessel wall anti-coagulant therapy cocaine - ↑bp
most susceptible vessels that will rupture and cause intraparenchymal hemorrhage
lenticulostriate vessels supplying BASAL GANGLIA + internal capsule
charcot-bouchard aneurysm of these vessels → rupture → hemorrhage
irreversible damage to brain occurs after
5 minutes of hypoxia (vs 20 minutes after MI)
most vulnerable locations for ischemic stroke
hippocampus
neocortex
cerebellum
watershed areas - with severe hypotension, first affected since most distal
watershed areas in brain: receive dual blood supply
MCA/ACA
MCA/PCA
causes of hemorrhagic stroke (ischemia)
primary cause: rupture of vessels (esp BASAL GANGLIA - lenticulostriate a.) amyloid angiopathy vascular malformations vasculitis neoplasm growing in vessel wall anti-coagulant therapy cocaine - ↑bp secondary cause: reperfusion of ischemic stroke (↑ vessel fragility)
reversible episode of focal ischemia with no acute infarction is caused by
transient ischemic attack
negative MRI: but treat as ischemic stroke since can’t wait for MRI results
ischemia → infarction of neural tissue → liquefactive necrosis is caused by
acute ischemic stroke
causes of ischemic strokes
thrombotic:
thrombosis over atherosclerotic plaque in carotid → embolizes to brain (MCA most common)
embolic:
afib → thrombus in LA → brain
infective endocarditis → septic emboli
DVT with patent foramen ovale → RA to LA → brain
broken long bone, pelvis → fat emboli
when can thrombolytic (t-PA, streptokinase, or urokinase) be given for ischemic stroke patient
if wake up with stroke symptoms can you give thrombolytics?
no - assume stroke began 9 hrs ago - no longer a candidate
imaging diagnosis of ischemic stroke
bright on diffuse-weighted MRI in 3-30 minutes (highest sensitivity for early ischemia)
if considering a stroke in a patient first step in management:
order CT scan of head w/o contrast
if acute bleed (white): consider hemorrhagic stroke
otherwise consider ischemic stroke
when can thrombolytic (t-PA, streptokinase, or urokinase) be given for ischemic stroke patient
less than 3-4 hrs
artery damaged:
unilateral facial and arm sensory and/or motor loss
MCA
artery damaged:
unilateral lower extremity sensory and/or motor loss
ACA
artery damaged: broca or wernicke aphasia (if dominant - usually left lobe) OR hemispatial neglect (if nondominant - usually right lobe)
MCA
aneurysm of this artery may cause:
bilateral loss of lateral visual fields
anterior communicating aneurysm - compresses optic chiasm
aneurysm of this artery may cause:
eye to look down + out
posterior communicating aneurysm - CN3 damage
