Stroke Flashcards
(34 cards)
what supplies the brain?
internal carotids (anterior 3/5 of brain) vertebral arteries (posterior 2/5 of brain)
uses up 20% of total body oxygen
what is a TIA?
transient ischemic attack - brief rapid period of inadequate cerebral perfusion leading to a sudden loss of neurologic function with no permanent defects and full resolution
what are the 2 causes of TIA?
intermittent vessel obstruction (plaque, thrombus) or temporary vasospasm (smoke, drugs, stress, migraine)
how do you dx a TIA?
carotid auscultation (listen to blood vessel in neck), carotid ultrasound or echocardiogram (heart ultrasound)
what are the symptoms of TIA?
hemiplegia, diplopia, amaurosis fugax, vertigo, loss of speech, understanding, or balance
what is a stroke?
5 in cause of death in US
disturbance of blood supply causing loss of brain function with permanent damage
how do you confirm a dx of stroke?
CT/CTA: confirm stroke + if ischemic / hemorrhagic
- metal imaging + no pregnancy use bc radiation
MRI: ID and localize the site and source of stroke
- no radiation so safe for pregnancy but no metal imaging
what are the two types of strokes?
how does it differ between adults and children?
ischemic (80-85%) with 40% mortality rate
Hemorrhagic (15-20%) with 80% mortality rate
Children: ischemic + hemorrhagic percentages are the same
- pay attention to other risk factors like clotting disorders, vascular abnormality, contraceptives
What are the two MOA of ischemic strokes?
1: blood vessel occlusion (thrombus, embolus, lacunar, dissection)
2. systemic hypoperfusion due to pump failure or hypovolemia
what is an embolic stroke and what causes it?
arteriovenous thrombosis + plaque fragments from carotid leading to ischemia and chronic afibrillation
It can be caused by fat particles, gas bubbles, bacterial endocarditis (roth spots) and IV substance abuse (insoluble in blood) ~ Talc Retinopathy whitens the retina
how do you treat ischemic strokes?
tPA: tissue plasminogen activator that dissolves the clot and restores blood flow BUT it can cause hemorrhage and has to be within 3 hours of stroke
only 1-7% used
what is the MOA of hemorrhagic strokes?
intracranial artery rupture leading to hypoxic and hydraulic damage (more fluid = high ICP)
sudden onset + severe HA from the increased fluid
what is the cause of hemorrhagic strokes?
HTN** or aneurysm, AVM, trauma
what are the 2 types of hemorrhagic strokes
Extra-Axial (inside skull but outside brain)
Intra-axial (inside brain) - rupture and hemorrhage into brain leading to hypoxic and hydraulic damage
- associated with HTN»_space;> AVM, Berry Aneurysms and Trauma
What are the 3 types of extra-axial injuries?
epidural: caused by head trauma + middle meningeal artery (80%) with lenticular shape hematoma
- bleeds into space between skull and dura
Subdural: caused by A/D injury (vein > artery)
- mostly elderly or young
- crescentic shape hematoma
subarachnoid: more young than elderly; caused by saccular aneurysm rupture (80%) or trauma, AVM
- fluid into SAS – papilledema and HA
what arteries are most commonly affected with strokes?
middle cerebral artery: feeds the occipital lobe which leads to VFD + numbness, weak, speech, language
posterior cerebral artery: only VFD
what are the 3 ways a brain can show injury
lose consciousness, seizures, localizing signs (loss of function)
how do blood signals change over time?
over time, iron is broken down and density of blood changes
Acute (3 days): hyperintense
Chronic (14+ days): hypointense
what are the localizing signs of acute CVA
sudden severe HA, hemiplegia, hypoesthesia (1 sided numb), aphasia, VFD, EOM restriction, confusion, bizarre behavior, personality change
What does FAST stand for
Face
Arm
Speech
Time
What is the left hemisphere responsible for?
sensory/motor of the right side speech, language, comprehension Analysis and Calculations Time and Sequencing Aphasia + Dysarthria Right-sided Hemiparesis, VFD, Neglect Poor Conjugate Right Gaze Difficulty reading and writing
what is the right hemisphere responsible for?
sensory and motor of left side Spatial Ability / Spatial Disorientation Creativity Context/Perception Poor Conjugate Left Side Left sided VFD, Neglect, Hemiparesis Recognize faces, objects, places Dysarthria possible
What is the Frontal Lobe responsible for?
Precentral Gyrus (motor cortex) Paralysis and motor defects FEF (Eye movements) Inability to Express Language (Broca's Area) Personality / social changes Difficulty with problem-solving or decision-making inability to sequence events difficulty with impulse control low attention
What is the Parietal Lobe responsible for?
Inability to name object
decreased spatial perception (L/R coordination)
sensory defects (postcentral gyrus: sensory cortex)
VFD: visual neglect (left sided neglect more common)
Difficulty drawing objects, reading, writing, math
