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Neuro > Cerebral and Lacunar Strokes B&B > Flashcards

Cerebral and Lacunar Strokes B&B Flashcards

1
Q

what are the etiologies of strokes (2)? what is the best first test for diagnosis?

A
  1. 80% ischemic - thrombosis, embolism, hypoperfusion —> symptom onset over hours
  2. 20% hemorrhagic —> sudden onset

first test: non-contrast CT of head

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2
Q

you suspect your patient is having a stroke - what is the first test you should run?

A

non-contrast CT of head

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3
Q

what part of the body will display symptoms from stroke of the ACA vs MCA vs PCA? (think of the homunculus)

A

ACA: lower limb (supplies superior overlying strip of the cortex and the medial sides of the hemispheres)

MCA: upper limb, face (supplies most of cerebrum, lateral portion)

PCA: vision (supplies occipital lobe)

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4
Q

how do MCA strokes present? (4)

A

most common site of stroke

  1. contralateral motor/sensory symptoms
  2. arms (>legs) + face (think of homunculus)
  3. spastic (UMN) paralysis
    4a. left sided - aphasia (speech center is L in most patients)
    4b. right sided - hemineglect
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5
Q

what is the most common site of stroke, and how does it present?

A

middle cerebral artery (MCA)

  1. contralateral motor/sensory symptoms
  2. arms (>legs) + face (think of homunculus)
  3. spastic (UMN) paralysis
    4a. left sided - aphasia (speech center is L in most patients)
    4b. right sided - hemineglect
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6
Q

Pt is 75yo M presenting with acute onset of loss of movement in his R arm and drooping of the R face with drooling from the corner of his mouth. Pt has difficulty speaking.

What is most likely going on? Be exact.

A

stroke of L MCA (MCA = most common site of stroke)

  1. contralateral motor/sensory symptoms
  2. arms (>legs) + face (think of homunculus)
  3. spastic (UMN) paralysis
    4a. left sided - aphasia (speech center is L in most patients)
    4b. right sided - hemineglect
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7
Q

how will MCA stroke affect facial function?

A

recall upper face has dual innervation by R and L UMN - unaffected by unilateral MCA stroke

lower face has single UMN supply from contralateral motor cortex fibers running in corticobulbar tract - MCA stroke will cause UMN damage (spastic paralysis)

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8
Q

how does ACA stroke present?

A

ACA (anterior cerebral artery) supplies medial cortex (midline portion) —> causes symptoms in lower extremities (think of homunculus with legs hanging over the edge)

legs > arms

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9
Q

Pt is 75yo M presenting with acute weakness in his R hip and leg. PE reveals decreased sensation to pinprick and vibration in his R leg. What is the most likely diagnosis? Be exact.

A

stroke of L ACA (anterior cerebral artery)

ACA (anterior cerebral artery) supplies medial cortex (midline portion) —> causes symptoms in contralateral lower extremities (think of homunculus with legs hanging over the edge)

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10
Q

how does a PCA stroke present? (3)

A

recall PCA (posterior cerebral artery) supplies posterior brain (duh!) and therefore visual cortex

  1. visual hallucinations
  2. visual agnosia
  3. contralateral hemianopia with macular sparing (dual innervation by PCA + MCA)
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11
Q

Pt is 80yo M presenting with acute visual loss on the R side. His wife reports he is seeing people not in the room. PE is negative for motor or sensory deficits. Visual exam shows loss of the L medial and R lateral fields with macular sparing. What is the diagnosis? Be exact.

A

stroke of L PCA (posterior cerebral artery)

recall PCA (posterior cerebral artery) supplies posterior brain (duh!) and therefore visual cortex

  1. visual hallucinations
  2. visual agnosia
  3. contralateral hemianopia with macular sparing (dual innervation by MCA + PCA)
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12
Q

explain why PCA strokes spare the macula

A

macula: central, high-resolution vision (reading)

has dual blood supply from middle (MCA) and posterior (PCA) cerebral arteries

PCA strokes (affecting occipital lobe) often spare the macula

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13
Q

stroke of which artery can present with thalamic syndrome? how will this present?

A

posterior cerebral artery (PCA) strokes

—> contralateral total sensory loss of face, arms, legs + proprioception deficit [recall thalamus is sensory relay]
but NO motor deficits

may result in chronic pain on contralateral (affected) side

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14
Q

what are 3 possible causes of hypoxic encephalopathy?

A
  1. shock
  2. anemia
  3. repeated hypoglycemia

loss of consciousness can occur in <10 seconds, permanent damage <4 mins (no glycogen storage in neurons!), can result in coma/ vegetative state

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15
Q

which 2 populations of neurons are highly susceptible to hypoxic encephalopathy?

A
  1. pyramidal cells of hippocampus
  2. Purkinje cells of cerebellum

hypoxic encephalopathy can be caused by shock, anemia, repeated hypoglycemia

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16
Q

what occurs in a “watershed infarct”?

A

most distal branches of major arteries of cerebrum (ACA, MCA, PCA) / where the zones of supply border each other are most vulnerable to ischemia

classic scenario - CNS damage after massive MI —> “man in a barrel” (bilateral proximal weakness with sparing of face, hands, feet)

17
Q

what is the classic presentation of watershed infarct?

A

watershed areas: supplied by distal branches of cerebral arteries / border zones between cerebral arteries (ACA, MCA, PCA)

classic scenario - CNS damage after massive MI
—> “man in a barrel”: bilateral proximal weakness (shoulders/thighs) with sparing of face, hands, feet

18
Q

what are lacunar strokes, and what are they associated with?

A

anatomically small strokes which resolve and leave lacunae (empty spaces) in brain - may not show on initial CT

associated with HTN!!, diabetes mellitus, smoking

19
Q

what’s signs will NOT be present in a patient with a lacunar stroke?

A

“cortical signs” seen in ACA/MCA/PCA strokes such as aphasia, agnosia, hemianopia will NOT be seen in lacunar infarcts

this is because lacunar strokes are of small artery branches supplying very small regions of the brain

20
Q

what are 4 common locations of lacunar strokes?

A
  1. internal capsule —> hemiparesis (arms = legs)
  2. thalamus —> sensory loss
  3. basal ganglia
  4. pons
21
Q

how will hemiparesis caused by a lacunar stroke differ from that of an MCA or ACA stroke?

A

lacunar stroke causing hemiparesis would be affecting internal capsule, so symptoms of legs = arms

MCA would affect arms > legs, while ACA would affect legs > arms (think of homunculus!)

22
Q

the following arterial branches are commonly affected by lacunar strokes - from which arteries are these branches derived?
a. lenticulostriate branches
b. anterior choroidal artery
c. recurrent artery of Heubner
d. thalamoperfornate branch
e. paramedian branches

A

a. lenticulostriate branches (most common) - MCA
b. anterior choroidal artery (also common) - ICA (internal carotid)

c. recurrent artery of Heubner - ACA
d. thalamoperfornate branch - PCA
e. paramedian branches - basilar artery

23
Q

what is required for a lacunar stroke to develop?

A

arteriolar sclerosis (due to HTN)

proposed causes of lacunae (holes) left in brain are either lipohyalinosis (small vessel destruction + necrosis) or microatheroma (macrophages in vessels), but the jury is still out

24
Q

what are the 5 types of lacunar strokes? what part of the brain is damaged as a result of each type?

A
  1. pure motor - posterior limb of internal capsule
  2. pure sensory - VPL (ventral posteriolateral) thalamus (sensory relay nucleus)
  3. sensorimotor - thalamus, internal capsule, caudate and putamen, pons
  4. ataxic hemiparesis - base of pons, internal capsule (weakness, dysarthria, ataxia out of proportion to weakness)
  5. dysarthria-clumsy hand syndrome - pons, internal capsule
25
Q

what part of the brain is affected by each of the following types of lacunar stroke?
1. pure motor
2. pure sensory
3. sensorimotor
4. ataxic hemiparesis
5. dysarthria-clumsy hand syndrome

A
  1. pure motor - posterior limb of internal capsule
  2. pure sensory - VPL (ventral posteriolateral) thalamus (sensory relay nucleus)
  3. sensorimotor - thalamus, internal capsule, caudate and putamen, pons
  4. ataxic hemiparesis - base of pons, internal capsule (weakness, dysarthria, ataxia out of proportion to weakness)
  5. dysarthria-clumsy hand syndrome - pons, internal capsule
26
Q

a patient is presenting with weakness, dysarthria, and ataxia which is out of proportion to their weakness - what type of stroke is most likely occurring, and where?

A

ataxic hemiparesis subtype of lacunar stroke, affecting the base of the pons and internal capsule

27
Q

hemiballism is due to damage to the _____

A

subthalamic nucleus (part of basal ganglia)

[seen in rare subtypes of lacunar strokes]

28
Q

who will be the classic patient to present with a lacunar stroke?

A

patient with uncontrolled HTN and a negative initial CT scan of head (because lacunar strokes affect very small branches)

symptoms will present with 1 of 5 subtypes (if motor involvement, legs = arms due to internal capsule damage)

29
Q

which neurons are most vulnerable to ischemia? (3)

A
  1. pyramidal neurons of cortex - located in layers 3, 5, and 6 (—> cortical laminar necrosis)
  2. pyramidal neurons of hippocampus - located in temporal lobe, transfers info to long-term memory
  3. Purkinje layer of cerebellum
30
Q

what are the 3 ways ischemic stroke can develop?

A
  1. thrombotic stroke: atherosclerosis of blood vessel, plaque ruptures which exposes sub-endothelial collagen and formation of thrombus which cuts blood supply —> pale infarct
  2. embolic stroke: thrombo-embolus from circulation (ex, from left heart) lodges within blood vessel which cuts blood supply - neurons die, but then embolus is lysed —> hemorrhagic infarction
  3. lacunar stroke: secondary to hyaline arteriosclerosis, most commonly involves lenticulostriate vessels
31
Q

what is the cause of a pale infarct?

A

thrombotic stroke: atherosclerosis of blood vessel, plaque ruptures which exposes sub-endothelial collagen and formation of thrombus which cuts blood supply —> pale infarct in periphery of cortex

usually develops at branch points

32
Q

what is the cause of a hemorrhagic infarction?

A

embolic stroke: thrombo-embolus from circulation lodges within blood vessel which cuts blood supply - neurons die, but then embolus is lysed —> hemorrhagic infarction at periphery of cortex

usually involves middle cerebral artery

most often embolus from left heart, classically in the context of atrial fibrillation

33
Q

what is the result of a thrombotic stroke vs embolic stroke?

A

thrombotic stroke: atherosclerosis of blood vessel, plaque ruptures which exposes sub-endothelial collagen and formation of thrombus which cuts blood supply —> pale infarct

embolic stroke: thrombo-embolus from circulation (ex, from left heart) lodges within blood vessel which cuts blood supply - neurons die, but then embolus is lysed —> hemorrhagic infarction

34
Q

what is the cause and most common location of intracerebral hemorrhage?

A

rupture of Charcot-Bouchard micro-aneurysms - complication of HTN, hyaline arteriosclerosis causes weakening of vessel walls (aneurysm forms, then bursts)

most commonly affects basal ganglia (lenticulostriate arteries)

35
Q

describe how the lenticulostriate arteries can develop lacunar strokes OR intracerebral strokes

A

both complications of HTN!

lacunar stroke: hyaline arteriosclerosis causes decreased blood flow —> ischemic

intracerebral stroke: hyaline arteriosclerosis causes rupture of Charcot-Bouchard micro-aneurysms due to weakening of the vessel wall —> hemorrhage

36
Q

bleed on the bottom of the brain =

A

subarachnoid hemorrhage

37
Q

where do subarachnoid hemorrhages most frequently occur? why?

A

most frequently due to rupture of berry aneurysm, which are most frequently located in branch points of anterior communicating artery

this is because the branch points lack a media layer (only has intima + adventitia) - the walls are thinner/weaker here

therefore, berry aneurysms lack a media layer! makes it susceptible to rupture

38
Q

berry aneurysms are associated with… (2)

A
  1. Marfan syndrome
  2. ADPKD (AD polycystic kidney disease)

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