stroke Flashcards
what are the extracranial symptoms that affect stroke?
Systemic blood output (MAP)
Cardiac output
Viscosity of blood
what are the intracranial factors that affect stroke?
INTRACRANIAL PRESSURE
atherosclerosis
blood vessels
how many types of stroke are there?
2, ischemic and haemorrhagic.
TIA is under ischemic
what are the causes of ischemic stroke?
thrombotic:
- htn
- atherosclerosis
-large vessel (MCA infarct)
- small vessel (lacunar infarct)
embolic
-dislodge of blood clots
>carotid plaque
>atrial fibrillation
>atherosclerotic plaque
what is the difference between thrombotic and embolic clots?
thrombotic clots form in the arteries that supply the brain
embolic clots form elsewhere in the body and travels through the blood stream
what are the causes of haemorrhagic stroke?
ICH- intracerebral
-HTN
-thrombolytic drugs
SAH- subarachnoid harmorrhage:
- aneurysm rupture
what is ICH? what is its characteristics?
it is bleeding in the brain and it occurs without warning
what is SAH and what is its characteristics?
bleeding in the subarachnoid space
severe headache- thunderclap headache. CT shows a star shaped image.
associated with activities
What is FAST?
FACIAL DROOP
ARM WEAKNESS
SPEECH DIFFICULTY
TIME TO CALL 995
what is MAP and what can u tell based on a MAP?
what is the normal value?
Mean arterial pressure - systemic blood pressure
it is a better indicator of perfusion to vital organs than systolic BP.
it should be maintained at MAP>65
which arteries are involved in TIA?
carotid arteries and vertebrobasilar arteries
what happens when the carotid arteries are affected in TIA? what symptoms will be presented?
transient loss of vision in 1 eye
hemiparesis
inability to speak
what are carotid arteries?
they are major blood vessels that supply blood to head and brain. impt to maintain normal brain function
what are vertebrobasilar arteries?
tehy are a pair of major blood vessels that supply to the posterior part of the brain and brainstem.
what symptoms are presented when the vertebrobasilar arteries are affected?
tinnitus
verigo and blurring vision
hemiparesis
what are the acute management in ED? (7)
1) assess ABCs and v/s
2) provide oxygen if hypoxemic
3) Obtain IV access and labs
4) Check CBG
5) Perform neurologic screening, GCS, NIHSS
6) Activate stroke team, STAT CT brain
7) 12 lead aECG
what are the diagnostic tests for stroke?
CT brain (hemorrhagic)
MRI (ischemic)
Angiogram (aneurysm)
Carotid u/s
2D echo (size, shape of heart, detect blockage)
EEG
what is the CT brain good for?
-identify haemorrhage and boney injury
it does not show early ischemia/ anoxia - absence of O2
What is MRI good for?
- it is more useful than a CT scan to diagnose ischemic stroke within 12 hours of the first symptom
what is CT angiogram good for?
- identify thrombus in major vessels or vascular malformations such as aneurysm
what does a spot sign in CT angiogram mean?
contrast extravasation into haematoma showing active bleed.
what is 1 con of CT Angiogram?
iodinated contrast can cause allergic reactions and kidney injury.
what is ischemia?
a reduction in blood flow that can last for several seconds to a few minutes
what is infarction
If there is cessation of flow for than a few minutes, infarction of brain tissue occurs
● Ischemia or infarction may be focal (brain vessels) or generalized
explain the pathophysiology of ischemia stroke
Reduce blood flow in the arteries can be thrombosis or embolism
● Reduction in blood flow deprives the cells of O2 and glucose
● Lack of energy causes membrane dysfunction and entry of ions
● Edema of cells occurs, followed by death of cells
● Vascular changes aggravate edema
water follows ions hence causes edema
what is a core and penumbra?
Core: ischemic area
Penumbra: hypoxia of cells near area of original insult over time hence need
to
protect penumbra by ↑ O2 transport to the danger zone, limit cell death
what are the causes of thrombosis?
Arterial disease
○ Atherosclerosis, arteritis
● Blood disorders
○ Thrombocytosis, polycythemia
explain the process of atherosclerosis
Fatty streaks in intima layer
○ Oxidation of LDL cholesterol by free radicals released by macrophages, endothelial cells, smooth
muscle cells
○ Platelet & fibrin deposition as a result of endothelial injury
○ Accumulation of complex lipids, proteins, and carbohydrates, proliferation of cells in intimal layer of an
artery
○ Plaque formation > rupture >thrombosis
what is stroke in evolution and how does it occur?
Increasing obstruction may involve a proximal branch of the artery and increase the deficit:.
the damage can continue for several days
does resolution of edema after the acute stage help to restore function?
yes
list the common sites for ICH
basal ganglia, thalamus, pons cerebellum
symptoms of anterior cerebral artery stroke
prefrontal lobe: confusion, disorientation
medial surface: paralysis, sensory loss in the opposite leg
apraxia, abulia, urinary incontinence,
signs and symptoms of right side brain damage
- paralysis of left side
- spatial perceptual deficits
- quick and impulsive
- performance memory deficit
signs and symptoms of left side brain damage
- paralysis of right side
- speech language deficit
- slow and cautious
- language memory deficit
inclusion criteria for iv rtpa
18 years and above
Time from “last seen well”
< 4.5 hours
Ischemic stroke with
significant neurological
deficit NIHSS > 4
exclusion criteria for iv rtpa
Evidence of ICH or SAH
Active internal bleeding
Stroke or HI within 3 mths
Platelet < 100,000
On anticoagulation (warfarin)
or INR > 1.5 or PT > 15
Received heparin within 48hrs
and aPTT elevated above
normal range
BSL < 2.7 or > 22.2mmol/l
Inclusion Exclusion
