Lecture 2.2

Question 1

What is essential when trying to localize stroke symptoms?

Answer 1

Knowing the blood vessel territories

Question 2

1) What does Broca’s area do? Where is it?
2) What does Wernicke’s area do? Where is it?
3) Where is the primary visual cortex?
4) How are these three things relevant to strokes?

Answer 2

1) Broca’s area (expressive speech) left hemisphere in the superior to Sylvian fissure in frontal lobe
2) Wernicke’s area (language processing/receptive speech) inferior to lateral fissure in temporal lobe
3) Primary visual cortex is in the occipital lobe
4) Often affected by strokes

Question 3

1) What supply the anterior hemispheres of the brain?
2) What supply the posterior hemispheres of the brain? What do they join to form?

Answer 3

1) Anterior: Internal carotid arteries
2) Posterior: Vertebral arteries; form basilar artery

Question 4

What do the the anterior and posterior blood supplies to the brain form? Why is it important?

Answer 4

An anastomotic ring called the Circle of Willis from which all major cerebral vessels arise

Question 5

What percent of the population has a complete Circle of Willis?

Answer 5

About 1/3 of the general population

Question 6

What arteries are a part of the Circle of Willis?

Answer 6

1) Basilar
2) Anterior and posterior communicating
3) Anterior and posterior cerebral
4) Internal carotids

Question 7

1) Where do the common carotid arteries originate? What do they split into?
2) What are the main arteries that supply the cerebral hemispheres?

Answer 7

1) Come off the aorta and split into the internal and external carotid arteries
2) Anterior, middle and posterior cerebral arteries (ACA, MCA, PCA)

Question 8

What are the termination of the internal carotids?

Answer 8

Anterior and middle cerebral arteries

Question 9

1) What links the anterior cerebral arteries to each other? Where?
2) How are the anterior and posterior circulations linked?

Answer 9

1) Join anteriorly by the anterior communicating artery.
2) By the posterior communicating arteries

Question 10

What do the posterior communicating arteries join at each end?

Answer 10

The internal carotids and the posterior cerebrals

Question 11

1) What do the 3 main cerebral arteries (ACA, MCA, PCA) supply?
2) Describe the route of the anterior cerebral artery (ACA).
3) What does the ACA supply?

Answer 11

1) Have many branches that supply the surface of the brain & the deep brain structures
2) Travels forward, splits into 2 main branches, then turns back over the corpus collosum.
3) The cortex on the anterior medial surface of the brain from frontal to anterior parietal lobe, as well as the medial sensorimotor cortex.

Question 12

1) Describe the route of the middle cerebral artery (MCA).
2) What does the MCA supply?

Answer 12

1) Enters Sylvian Fissure and then splits into 2-4 main branches. These branches form loops.
2) The cortex above and below the Sylvian Fissure including the lateral temporal lobe and parts of the parietal lobe

Question 13

1) Describe the route of the posterior cerebral artery (PCA).
2) What does the PCA supply?

Answer 13

1) Curves back off the basilar artery and has many branches
2) The inferior and medial temporal lobes and the medial occipital cortex.

Question 14

1) What supplies large regions of the basal ganglia and the internal capsule?
2) What happens to these during HTN? What can this cause?

Answer 14

1) Branches of the middle cerebral artery
2) These small vessels are prone to narrowing, which can lead to blockages causing lacunar infarctions (an area of the vessel infarcts and leaves a hole or depression in the brain)

Question 15

What can cause lacunar infarctions? What are lacunar infarctions?

Answer 15

Branches of the middle cerebral artery are small and prone to narrow during HTN, leading to blockages which infarct and leave a small hole or depression in the brain

Question 16

1) What supply blood to the thalamus and posterior limb of the internal capsule?
2) What does the internal capsule house?
3) What can a lunar infarction cause in that area?

Answer 16

1)Some small branches of the MCA
2) Motor pathways in the corticospinal tract
3) Contralateral hemiparesis.

Question 17

1) What type of strokes are more common, MCA, ACA, or PCA?
2) What can this type of stroke cause?

Answer 17

1) MCA strokes are more common
2) Aphasia, hemineglect, hemianopia, face/arm or face/arm/leg sensorimotor loss. Patients often have a gaze toward the side of the lesion.

Question 18

1) Define lacunar infarct syndrome and where it is
2) What can it be characterized by?

Answer 18

1) The clinical manifestations of a lacunar infarct; location ex/posterior limb of internal capsule.
2) Can be characterized by pure motor hemiparesis: Contra/Unilateral face, arm and leg weakness.

Question 19

If a patient has a gaze toward the side of the lesion, what kind of stroke may they have had?

Answer 19

MCA (middle cerebral artery)

Question 20

What are two causes of two cerebral arteries being compromised? [and thus causing watershed infarction]

Answer 20

1) Sudden occlusion of the internal carotid or
2) A drop in BP in setting of carotid stenosis

Question 21

1) What do the effects of watershed infarcts depend on?
2) What can watershed infarcts cause?

Answer 21

1) Depending which 2 cerebral arteries are affected
2) Watershed infarcts can cause arm and leg weakness, aphasia and visual processing deficits, etc

Question 22

Define watershed zone

Answer 22

The region in-between the 2 vessels that is at high risk for ischemia or infarction

Question 23

Define watershed infarct

Answer 23

When the blood supply to 2 adjacent cerebral arteries is compromised, the region in-between the 2 vessels is at high risk for ischemia or infarction

Question 24

1) Define TIA (transient ischemic attack)
2) what are some sympotms
3) What are some causes?

Answer 24

A neurologic deficit/s caused by cerebral ischemia that last <24 hours (usually closer to 10 minutes)
2) Symptoms can include motor, sensory, visual, auditory, emotional or cognitive.
3) The most common causes are migraines, seizures, arrhythmias and hypoglycemia

Question 25

Why is it important to pay attention to TIAs?

Answer 25

TIAs can be a warning sign for a larger pending ischemic event

Question 26

1) ____% of patients with TIAs with have a stroke within 3 months.
2) When do most of those strokes within the 3 months occur?

Answer 26

1) 10%
2) Most of those within the next 48 hours

Question 27

1) What is the 5th leading cause of death in adults in the US and leading cause of significant disability?
2) Are strokes emergent?
3) What are the two main types of strokes?

Answer 27

1) Strokes
2) Yes, an emergent situation
3) Hemorrhagic or ischemic

Question 28

1) Define ischemic stroke
2) What can cause it?

Answer 28

1) Lack of adequate blood supply to the brain for long enough to cause cell death
2) Can be caused by embolus or thrombus

Question 29

1) What is an embolus?
2) What happens to it?
3) Is this gradual or sudden?

Answer 29

1) Piece of material that travels from one place to another within the vascular system, typically a blood clot (but can also be air, fat, contaminants)
2) Gets stuck at destination (when vessel gets too small for it to travel any further) thereby cutting off blood supply to whatever is downstream.
3) Typically occurs suddenly.

Question 30

1) Define thrombus
2) What causes it?
3) Is it sudden or gradual?

Answer 30

1) Clot/plaque forms on the blood vessel wall and causes it to occlude-it is local and DOES NOT travel.
2) Usually from a plaque.
3) Can have a slower onset

Question 31

1) What causes large vessel strokes?
2) What are small vessel strokes also called?

Answer 31

1) Large vessel strokes often caused by embolus
2) Small vessel strokes also called lacunar infarcts

Question 32

1) What is the treatment for an embolic stroke? What are emboli most often made of?
2) Where do emboli commonly come from?
3) What can create emboli? (2 things)

Answer 32

1) Need to find the source to prevent additional strokes; emboli are most often blood clots.
2) The heart.
3) Afib, or in areas of damaged cardiac tissue from previous MI, where slow moving or dead areas of cardiac muscle have stagnant blood flow and create emboli.

Question 33

1) Where can valvular disease thrombi form?
2) Where can artery to artery emboli come from?

Answer 33

1) On valve leaflets or artificial valves
2) From a stenotic area of another vessel

Question 34

What can dissection (tear of the inner wall of an artery) cause? In what arteries?

Answer 34

Dissection of carotids or vertebral arteries often form thrombi/clot, which can embolize to the brain

Question 35

List 6 potential causes of emboli

Answer 35

1) Aortic plaques can embolize
2) Air emboli ex/ divers, accidental introduction via IVs,
3) Septic emboli from bacterial endocarditis
4) Fat, from trauma to the long bones
5) Amniotic fluid emboli from childbirth
6) Illicit IV drug use and contaminates

Question 36

1) What do cortical signs come from?
2) What are they?
3) What can help locate brain lesions?

Answer 36

1) Cortex (lobar) strokes
2) Aphasia, neglect, homonymous visual field defects, apraxia, hemiparesis, and sensory loss.
3) Knowing the locations of these areas of the brain

Question 37

1) How often do headaches occur in ischemic stroke patients? What causes these headaches during a stroke?
2) What strokes are headaches most common in? What other symptoms can they have?

Answer 37

1) In about ¼ of ischemic patients; from the innervation of the blood vessels and meninges (not the actual brain cells).
2) More commonly seen in posterior strokes and can include neck pain if carotids or vertebral arteries are involved

Question 38

How often are seizures associated with strokes?

Answer 38

In about 3-10% of patients.

Question 39

List common risk factors of strokes

Answer 39

HTN, DM, hypercholesterolemia, cigarette smoking, positive family history, prior history of stroke or vascular disease, AFIB, mechanical valves, very low ejection fraction, obesity, sedentary lifestyle, hypercoagulable states, patent foramen ovale

Question 40

Why is a patent foramen ovale a risk factor of strokes?

Answer 40

Can allow an embolus from the venous system to bypass the lungs and go from the right to left side of the heart and on to the brain

Question 41

What types of patients are strokes usually seen in? Why?

Answer 41

Typically in older patients since risk factors accumulate and wear on the body; however can be seen in younger patients usually from dissection/trauma

Question 42

What typically causes dissections? In what arteries is this most common?

Answer 42

Head and neck trauma can cause a tear on the interior surface of an artery; commonly internal carotids or vertebral arteries.

Question 43

1) Carotid dissection can cause TIA or infarct in the _________ circulation.
2) Vertebral dissection can cause TIA or infarct in the _________ circulation

Answer 43

1) Carotid: anterior
2) Vertebral: posterior

Question 44

1) What veins drain the brain? Where do they drain into?
2) Where do they ultimately exit?

Answer 44

1) Deep and superficial veins drain the brain; they dump into dural sinuses.
2) Via the internal jugular veins

Question 45

1) Where are the cerebral venous sinuses?
2) What do they do and where do they dump into?

Answer 45

1) Lay near the dura and collect deoxygenated blood
2) Ultimately dump into the internal jugulars.

Question 46

What is the clinical significance of the cerebral venous sinuses?

Answer 46

-COVID19 can cause thrombus in the cerebral venous sinuses.
-This can block the outflow and cause back pressure which can lead to strokes, seizures, and death.