Cerebrovasculature & Stroke Flashcards
What is a blockage of a blood vessel resulting in lack of blood flow to an area of the brain called?
Ischemic Stroke
What is bleeding into the brain caused by a ruptured blood vessel called?
Hemorrhagic Stroke
Which type of stroke occurs more often (80% of the time)?
Ischemic
Stroke is ____ and occurs in _____
vascular/sudden/acute/focal; seconds to minutes
Although the brain is only 2% of the body’s weight, it is responsible for 15% of ____, 20% of ____ and 25% of ____
Cardiac Output
Oxygen Consumption
Total Body Glucose Use
The brain has a ___ energy reserve and relies on ___ metabolism to function normally
low; aerobic
The brain requires a continuous supply of ___ and ___. If hypoperfusion (reduced blood flow) occurs, it will rapidly lead to ____ and even ____
oxygen and glucose
neuronal injury and death
If soidum/potassium ATPase function decreases, intracellular potassium ____ and intracellular sodium ____, which leads to increased _____ and resulting cytotoxic edema (cell swelling)
decreases
increases
water
Cytotoxic Edema can be visualized on what type of MRI sequences?
DWI/ADC
Cytotoxic Edema can occur within minutes of what?
an ischemic stroke
Vasogenic Edema develops after _____ and peaks after _____
a few hours; several days
Increased permeability of capillary and endothelial cells leads to movement of water into the interstitial space. This is called what?
Vasogenic Edema
Vasogenic Edema is visualized on what type of MRI sequences?
T2/FLAIR
Vasogenic Edema appears hypodense on what imaging, therefore, should be ordered if it is suspected?
Head CT
Cytotoxic Edema is NOT visible on what imaging?
Head CT
What needs to be ruled out first when determining if a patient has had a stroke?
Intracranial Hemorrhage
In a stroke code, what neuro-imaging study is most appropriate and helpful?
Head CT because it is quick and sensitive to acute blood
Does a normal head CT rule out an ischemic stroke?
NO because cytotoxic edema is NOT visible on a CT and vasogenic edema takes a few hours to develop
Acute stroke imaging shows a normal CT scan and FLAIR scan less than ____ hours from onset, but abnormal DWI/ADC/FLAIR ______ after
6
hours-days
What is irreversibly damaged brain tissue called?
Infarct Core
What is the salvageable brain tissue in stroke called?
Pneumbra
What is the area of dead tissue resulting from failure of blood supply called?
Infarct
What is inadequate blood supply called?
Ischemia
Tissue viability is maintained by what?
Collateral circulation blood flow
Brain tissue dies rapidly without ______ due to dependence on continuous supply of what 2 things?
blood perfusion;
oxygen and glucose
Pneumbra tissue at the _____ of an infarct dies more slowly due to blood supply from collateral circulation
periphery
Acute stroke interventions to remove _____ are most successful when performed as soon as possible
blood clots
Artery occlusion results in focal brain injury to the areas supplied by ____
that artery
What are the 3 main categories of ischemic stroke?
- Large Vessel
- Small Vessel
- Cardioembolic
What are the 2 mechanisms of large vessel strokes?
- Thromboembolic
2. In situ thrombosis
What is the result of blood clots associated with artherosclerosis?
A large blood vessel stroke
What is a thromboembolic stroke?
traveling blood clot stroke
What is a in situ thromboembolic stroke?
blood clot that forms at its origin (stays put)
The ____ arteries join to form the basilar branches into the ____
vertebral; PCAs
The anterior circulation consists of ___, ____ and ___
ICAs, MCAs, ACAs
The posterior circulation consists of ___ arteries, ___ arteries and ____
Basilar, Vertebral, PCAs
___ branches into MCA and ACA
Internal carotids (ICAs)
The _____ artery connects the anterior and posterior circulation
PCOM - posterior communicating artery
ICA = ___ + ___
ACA + MCA
The lateral brain is supplied by the ____
MCA
The anterior brain is supplied by the ____
ACA
The posterior brain is supplied by the _____
PCA
The medial motor and sensory cortex is supplied by the ____
ACA
The primary visual cortex (occipital lobe) is supplied by the ____
PCA
The lateral portion of the primary motor and sensory cortices, language centers (left hemisphere) and spatial awareness (right hemisphere) are supplied by the ____
MCA
The ____ is the primary motor cortex and the ____ is the primary somatosensory cortex
precentral gyrus; postcentral gyrus
Cerebellar lesions cause deficits on the _____ side of the body
ipsilateral
Cortical signs of a large vessel stroke include aphasia (____ hemisphere) or neglect (____ hemisphere)
left; right
An anterior circulation stroke could affect which vessels?
MCA and ACA
MCA stroke causes _____ face/arm weakness or numbness and ____ if it includes the left hemisphere or ____ if it includes the right hemisphere
contralateral
aphasia
neglect
ACA stroke causes ____ leg weakness or numbness
contralateral
PCA stroke causes ____ visual field deficits
contralateral
A posterior circulation stroke could affect which vessels?
PCA, Basilar/Vertebral
Basilar/Vertebral strokes include ____ symptoms on the ipsilateral side such as ataxia (incoordination) or ____ symptoms such as cranial nerve deficits
cerebellar; brainstem
Broca’s is to _____ as Wernicke’s is to ___
mneumonic
“broken speech”; “warpspeed speech”
Aphasia is a disorder of ____ whereas Dysarthria is disorder of ____
language (production/comprehension) speech articulation (muscle movements)
Where does aphasia often localize?
Left Hemisphere
Left = Language
Where does dysarthria often localize?
Relatively Nonspecific
Which subcortical structure contains corticospinal motor pathways?
Internal Capsule
Broca’s area is ____ whereas Wernicke’s area is ____
expressive; receptive
What is it called if a patient exhibits clinical symptoms of both brocas and wernickes aphasia?
Global Aphasia
A patient exhibits non-fluent speech, but is aware of their deficits and has intact comprehension. What is this type of aphasia?
Broca’s aphasia
A patient exhibits fluent speech, but it is compared to “word salad” because of its paraphrasic errors and neologisms (new use of an old word). They have impaired comprehension and are unaware of their deficits (anosognosia). What type of aphasia do they have?
Wernicke’s aphasia
Neglect is localized to which lobe and subsequently affects what side of the body?
Right parietal lobe (localization); contralateral (left) side is ignored
Impaired attention to and awareness of one side of space is called what?
(hint: this is often related to doing the clock test)
Hemispatial Neglect
A patient exhibits right side weakness and numbness in their face and arm, and have aphasia. What type of stroke has occurred?
LEFT MCA stroke
A patient exhibits left side weakness and numbness in their face and arm, and have neglect. What type of stroke has occurred?
RIGHT MCA stroke
A patient exhibits weakness and numbness of the contralateral leg. What type of stroke has occurred?
ACA stroke
A patient exhibits contralateral visual field deficits. What type of stroke has occurred?
PCA stroke
A patient exhibits uncoordinated movements, dizziness, vertigo and other cerebellar/brainstem symptoms. What type of stroke has occurred?
Basilar/Vertebral
What is the strongest risk factor for a Lacunar stroke and why?
HTN because it wears and tears small delicate arteries
Small vessel stroke pathophysiology occurs when chronic ____ causes intrinsic changes to the small blood vessels, causing vessel wall ____ and lumen ____, which subsequently leads to _____
HTN
thickening
narrowing
occlusion
Specific pathologic changes in small vessel stroke include what? (3)
- Lipohyalinosis (vessel wall thickening and a resultant reduction in luminal diameter)
- Arteriosclerosis (thickening and hardening of the walls of the arteries, occurring typically in old age)
- Microatheroma (plaque)
What is Lipohyalinosis?
vessel wall thickening resulting in reduced lumen diameter
Vessel wall changes (weakening) can cause an artery rupture, which may lead to what type of stroke?
hemorrhagic stroke (focal)
T/F: Atherosclerosis of a large trunk vessel occluding the origin of a small vessel is quite common
false; LESS common
In small vessel anterior circulation, the MCA supplies what?
Lenticulostriate arteries
In small vessel posterior circulation, the PCA supplies what (perforating) arteries?
Thalamoperforators
In small vessel posterior circulation, the basilar arteries supply what (perforating) arteries?
Pontine Perforators
Cerebellar arteries in posterior circulation of small vessels include ___, ____ and ____
SCA, AICA, PICA
PICA is supplied by what artery in the posterior circulation?
vertebral
AICA and SCA are supplied by what artery in the posterior circulation?
basilar
The internal capsule and basal ganglia are supplied by what anterior circulation pathway?
MCA –> Lenticulostriate arteries –> int capsule and bg
The thalamus is supplied by what posterior circulation pathway?
PCA –> Thalamoperforators –> Thalamus
The pons is supplied by what posterior circulation pathway?
Basilar Artery –> Pontine Perforators –> Pons
The cerebellum and brainstem are supplied by what posterior circulation pathway?
Basilar/Vertebral –> SCA, AICA & PICA –> Cerebellum and Brainstem
Which type of stroke is more likely to cause motor/sensory deficits in more body parts?
small vessel strokes
Which type of stroke causes the entire contralateral hemibody to be affected?
small vessel strokes
Which type of stroke exhibits NO cortical signs?
small vessel strokes
In anterior circulation strokes (face/arm/leg weakness), fill in the blanks below:
- Weakness distribution:
- Face/Arm > Leg = ___ vessel
- Just Leg = ___ vessel
- Face/Arm/Leg ___ vessel or ____ (if this has occurred, proceed to #2 below to narrow down the vessel) - Cortical Signs? (aphasia or neglect?)
- If yes = ___
- If no + ____
- MCA; ACA; ICA (mca + aca) OR lenticulostriate
2. yes = ICA; no = lenticulostriate
What is a major risk factor for large vessel stroke?
Atherosclerosis
What type of stroke occurs when an embolus (blood clot) travels from the heart to the brain, where is lodges in a blood vessel and causes a stroke? (Commonly a result of A-Fib)
Cardioembolic Stroke
