27a - Ischemic Stroke

Question 1

define stroke

Answer 1

brain injury due to loss of blood supply or bleeding. Abrupt onset of FOCAL neurologic deficits. Often permanent disability or death

Question 2

define transient ischemic attack (TIA)

Answer 2

abrupt onset of FOCAL neurological deficits that RESOLVE within 1 hour.

Question 3

How can you tell the difference between ischemic and hemorrhagic stroke?

Answer 3

CT scan and??

Question 4

Describe CBF autoregulation and relation to MAP

Answer 4

CBF = MAP/CVR. CVR = cerebral vascular resistance. Ideally unrelated to MAP. Occurs when MAP >50 and <150.
If MAP falls below 50 or rises above 150 then linear relationship between MAP and CBF develops.
CBF threshold for infarction is 20.
In ischemic areas, CBF directly related to MAP

Question 5

what are risk factors for ischemic stroke?

Answer 5

nonmodifiable = age, gender, African amer, family history
Modifiable = HTN, diabetes, hyperlipid, smoking, afib, obesity, and inactivity

Question 6

What are signs and symptoms of ischemic stroke?

Answer 6

weakness or paralysis, loss of sensation, loss of vision in one eye or field, difficulty talking or understanding, difficulty with organization and perception, clumsiness and lack of balance

Question 7

What is clinical presentation for anterior circulation stroke?

Answer 7

ipsilateral blindness or contralateral inferior quadrantanopsia.
Contralateral gaze paralysis.
Contralateral mono/hemiparesis and/or sensory loss.
Aphasia in dominant hemisphere or neglect in nondominant

Question 8

What is clinical presentation for posterior circulation stroke?

Answer 8

unilateral, bilateral, or crossed (face/body) weakness and/or sensory defects.
Contarlateral homonymous hemianopsia or superior quadrantanopsia
Vertigo, N/V, gait ataxia, diplopia, dysphagia, Horner’s,
Altered consciousness and amnesia

Question 9

What is major vascular supply to major brain divisions?

Answer 9

Anterior = ICA, MCA, ACA
Posterior = PCA, VA, SCA, AICA, PAICA

Question 10

what are three major causes for ischemic stroke

Answer 10

occlusions, emboli, vasospasm

Question 11

What is differential diagnosis for ischemic stroke?

Answer 11

hemorrhagic stroke, subdural hematoma, syncope, radiculopathy, bell’s palsy, MS, brain tumor, migraine, seizure, glycimic problems, hypoxia

Question 12

Most common type of stroke?

Answer 12

ischemic strokes are 80%

Question 13

What is difference between focal necrosis and selective ischemic necrosis?

Answer 13

focal necrosis is death of all local cells.

selective is only death of brain neurons, and survival of suppporting glia

Question 14

What is the penumbra?

Answer 14

boundary area around an ischemic infarct. Ischemic center dies within hour, but penumbra can be saved if restored within 4-6 hours

Question 15

Is hyperglycemia good or bad for strokes?

Answer 15

bad. can accelerate brain injury

Question 16

Patient presents with sudden frontal eye field disturbances, comprehends and follows commands but can’t speak, and has several focal sensory and motor parasthesias. Where would angiogram show occlusion?

Answer 16

middle cerebral artery occlusion

Question 17

Patient presents with paralysis of an mostly entire side of the body: tongue, lips, face, thumb, fingers, hand, arm, shoulder, trunk, hip, ankle and toes. Where is the occlusion?

Answer 17

lenticulostriate arteries off of middle cerebral artery. Supplies the axons for almost entire motor cortex. Particularly bad.

Question 18

Patient presents with paralysis of larynx, tongue, lips, face thumb, fingers, hand and arm. Where is the occlusion?

Answer 18

main stem of middle cerebral artery

Question 19

CT scan shows necrosis of visual radiations, hippocampus, posterior corpus collosum, and thalamus. What artery was likely occluded?

Answer 19

posterior cerebral artery

Question 20

Patient has paralysis and numbness of hip, leg and foot as well as sudden behavior changes and lack of executive capability. Where is the occlusion?

Answer 20

anterior cerebral artery. Will knock out frontal lobe and motorsensory to hip,leg,foot.

Question 21

What is wallenberg syndrome?

Answer 21

medullary syndrome. stroke of PICA or vertebral artery.
Loss of pain/temp on ipsilateral face from lesion to spinal trigeminal nucleus/tract, loss of pain/temp on contralateral body due to lesion of spinothalamic tract, gait ataxia on ipsilateral side due to spinocerebellar tract lesion and dysarthria due to lesion of nucleus ambiguous

Question 22

What is a pontine stroke?

Answer 22

occlusion of small penetrating arteries from basilar. Gaze disorder due to lesion of MLF and CN 6.
Contralateral epicritic and proprioception loss due to medial leminiscus lesion.
Cerebellar lesions on both sides due to pontine nuclei lesion and transverse cerebellar fibers from both sides.
Contralateral hemiparesis due to corticospinal tract lesion

Question 23

What is Benedikt stroke?

Answer 23

Midbrain. Occlusion of PCA and or basilar artery.
ipsilateral CN 3 paralysis and pupil dilation due to loss of parasymp from edinger wesphal.
Contralateral epicritic loss due to medial leminiscus lesion.
Contralateral tremor and ataxia due to red nucleus lesion.

Question 24

What would cause contralateral gaze paresis?

Answer 24

anterior circulation

Question 25

What would cause aphasia in the dominant hemisphere or neglect in the nondominant?

Answer 25

anterior circulation

Question 26

Contralateral homonymous hemianopsia. Where is the occlusion?

Answer 26

posterior cerebral artery

Question 27

Vertigo, n/v, gait ataxia, diplopia, dysphagia, and horner’s syndrome. Where is the occlusion?

Answer 27

posterior circulation

Question 28

altered consciousness and amnesia. Where is the occlusion?

Answer 28

posterior circulation

Question 29

What is a lacunar stroke?

Answer 29

occlusion of small penetrating artery that causes small area of necrosis. Most common in internal capsule or pons.

Question 30

Where are atherothrombotic plaques most common?

Answer 30

origins of carotid and vertebral arteries or at the bifurcations

Question 31

What could cause multifocal occlusions?

Answer 31

CNS vasculitis such as collagen vascular diseases like lupus or giant cell arteritis

Question 32

What drugs can precipitate stroke?

Answer 32

cocaine, LSD, amphetamines - street
ethanol
Oral contraceptives with estrogen