B&B 7 Higher Cortical Info Flashcards Preview

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Flashcards in B&B 7 Higher Cortical Info Deck (84):
1

Where is language processed?

►Processed in dominant hemisphere

2

What connects Broca's & Wernicke's Areas?

Arcuate fasciculus and other peri-sylvain connections

3

What are Paraphasias?

►Phonemic (literal) paraphasias

4

Aphasia

...vs...

Dysarthria

...vs...

Apraxia


Aphasia
• an impairment of language produced by brain dysfunction

Dysarthria
• problem with the actual machinery making sounds
• "hardware problem"

Apraxia
• "software problem"
• Pts might be better at pronouncing individual sounds but will have a problem forming individual words

5

Aphasia

How is it classified?
(8 in total)

Non-Fluent Aphasias
– decreased output
– effortful
– decreased phrase length
– content words > function words (Aggramatic speech)
– paraphasias rare


Fluent Aphasias
– Normal (or increased) output
– No extra effort
– Normal phrase length
– Function words > content words (Empty Speech)
– paraphasias common

6

Non-Fluent Aphasias

Fluent Aphasias

What are they ...?

►Non-Fluent Aphasias
– Global A.
– Mixed transcortical A.
– Broca's A.
– Transcortical Motor A.

►Fluent Aphasias
– Wenicke's A.
– Transcortical Sensory A.
– Conduction A.
– Anomic A.

7

Global Aphasia

Non-fluent
Poor Comprehension
Repetition is impaired

8

Mixed transcortical Aphasia

Non-fluent
Poor Comprehension
Repetition is preserved

9

Broca's Aphasia

Non-fluent
Good Comprehension
Repetition is impaired

10

Transcortical Motor Aphasia

Non-fluent
Good Comprehension
Repetition is preserved

11

Wenicke's Aphasia

Fluent
Poor Comprehension
Repetition is impaired

12

Transcortical Sensory Aphasia

Fluent
Poor Comprehension
Repetition is preserved

13

Conduction Aphasia

Fluent
Good Comprehension
Repetition is impaired

14

Anomic Aphasia

Fluent
Good Comprehension
Repetition is preserved

15

What do all 8 classifications of Aphasia have in common?

Impaired Naming
(Difficulty assigning a name to an object)

16

What does Acute hemorrhage look like on CT?

Bright white

17

We image for stroke using CT.

WHAT do we see when we scan?

►3-4 hrs (earliest stages of embolic stroke)
– "Hyperacute Stroke"
– infarcted territory demonstrates subtle loss of density in the affected grey matter structures (cortex and basal ganglia) such that the grey matter and white matter have identical attenuation
– In up to 50% of cases, the embolus itself will be visible as an area of increased density (increased brightness on the CT image) in the occluded artery.

►Over the next 24-48 hours, the infarcted territory becomes more conspicuous as an area of low density
(darker on the CT image) with associated swelling.

►By 6 weeks, the infarct has become a well-defined area of low density similar to CSF with atrophy of the affected territory.

18

These lesions cause disruption to the BBB:
– an abscess
– an active demyelinating lesion in MS
– tumour

What doe we see on CT?

increased signal (ie, bright)

19

What is the blood supply?

Broca's Area
...vs...
Wernicke's Area

Broca's Area
– Sup. div MCA

Wernicke's Area
– Inf. div MCA

20

Anosognosia

What is this?

Deficit of self-awareness

a condition in which a person who suffers a certain disability seems unaware of the existence of his or her disability.

(eg) patient is not aware they cannot move one side of their body such as in Hemispatial Neglect

21

How to classify stroke?

►85% ischemic
(1/2 of these are in MCA)
– Large Artery Atherosclerosis
– Small Vessel Lacunar Stroke
– Cardioembolism (A fib, A flutter)
– Cryptogenic
– Others

►15% Hemorrhagic

22

Watershed Infarction

What is it?

‘cortical border zone infarction’
– Accounts for 5-10% of all ischemic cerebral strokes
– Between territories of 2 major arteries
– In carotid artery stenosis, the blood is not able to get there → this area becomes particularly vulnerable

23

What are the "4 P's" of acute stroke imaging?

►Parenchyma
►Pipes
►Perfusion → how is the circulation getting there?
►Penumbra → area at risk

24

What is the gold standard for stroke investigation?

MRI
– used in US
– limited access in BC
–There are practical limitations such as lengthy time required for imaging AND not for implant pts

25

What are our imaging modalities for stroke?

(practically speaking)

►NCCT
– Non-contrast CT
– Done on everyone

►CTP
– CT Perfusion
– Only on select few, only done in stroke centers
– good at assessing ischemic change

►CTA
– CT Angiogram
– Done on everyone

►T2WI
– T2 Weighted Image MRI

►DWI
– Diffusion Weighted Imaging MRI
– highly sensitive & specific
– lesion is bright white and may not occur on the previous imaging modalities
– BEST we have!

26

CTA

DSA

Ct Angiogram

Digital Subtraction Angiogram

27

What are the general timing guidelines for imaging after a stroke?

►4.5 hours for IV therapy
– TPA: Tissue Plasminogen Activator
– NOTE: the risk of bleeding due to TPA increases with time. Use onlly within 4.5 hours post stroke

►6 hours for interartieral therapy

►12 Hours for Posterior Circulation

28

What are the critical thresholds for perfusion?

CBF = Cerebral Blood Flow

CBF < 25ml/100g/min
– Neurological dysfunction

CBF 10-20 ml/100g/min:
– cell death minutes to hours

CBF < 10 ml/100 g/min
– cannot be tolerated beyond few minutes before infarction

29

MTT

What is it?

Mean Transit Time
– Time between arterial inflow and venous outflow
– Normal < 3 sec

– Sensitive to any kind of vascular disease
– Most predictive of fate of acutely ischemic tissue


30

CBV

What is it?

Volume of blood per unit of brain tissue
CBV = MTT x CBF

31

How bad of a problem is stroke?

3rd leading cause of death in Canada

Leading cause of disability

Massive health cost for acute care, rehab, and nursing home care → only 25% fully recover

32

What happens to the neurons during an ischemic crisis?

glutamate gets released, Ca rushes into the cell in massive excess → neuronotoxicity

33

What is the anatomy of the ischemic zone?

Ischemic Core (at center) surrounded by penumbra (area at risk)

34

What is TPA?

Tissue Plasminogen Activator
• Serine protease
• Converts Plasminogen to Plasmin
• Fibrinolytics
• The only effective FDA approved treatment for acute ischemic stroke
• needs to be given within 4.5 hrs. … the sooner the better!
• NNT = 8

35

What is Abulia?

• lack of will or initiative
• disorder of diminished motivation (DDM)
• A patient with aboulia is unable to act or make decisions independently.
• may range in severity from subtle to overwhelming
• aka "Blocq's disease"

36

Aboulia falls in the middle of the spectrum of diminished motivation

What is the continuum

least extreme
⬆︎
Apathy
Abulia
Akinetic Mutism
⬇︎
most extreme

37

ACA Stroke

(Anterior Cerebral Art.)

What are S/S?

• Leg > arm weakness
• Leg > arm numbness
• Abulia

38

MCA Stroke

• Hemiplegia
• Cortical features:
– Aphasia
– Neglect
– Visual field deficit
– Gaze deviation

39

Posterior Circulation Stroke

S/Sx?

• Visual field defect
• Vertigo
• Diplopia
• Ataxia
• Dysphagia
• Weakness
• Numbness

AFFECTING BRAINSTEM!

40

How do we treat High Grade Stenosis?

Carotid Endarterectomy
– removal of plaque from internal carotid by vascular surgeon

41

ASA
...vs...
Clopedigrel
(Plavix)

►ASA
– Inhibits COX enzymes
MOA: anti-platelt actions are due to irreversible acetylation of COX-1 in platelets, preventing their action

►Clopedigrel (Plavix)
– MOA: irreversibly inhibits P2Y12 receptor, an adenosine diphosphate (ADP) chemoreceptor on platelet cell membranes.

42

A fib patients

What do they need to be on?

Anti-coagulant!
• Recently there has been a huge campaign to get all A fib pts on clot prophylaxis
• reduces stroke risk much more effectively than ASA in A fib patients

Warfarin
– Good option, but there is hesitancy because of need to get regular INRs and risk of bleed

Factor 10a inhibitors
– Apaxiban, Rivaroxabin, Dabigatran
– awesome drugs!

43

Thrombosis
...vs...
Embolus

►Thrombosis
– forms locally in a vessel

►Embolus
– usually a peice of a thrombus that has broken free and is carried through blood
– OR, could be air (bends), fat, cancer cell, or bacteria (infective endocarditis)
(eg) Pulm embolus
(eg) Cardioembolism - A flut, A fib

44

In a stroke, which direction do the eyes look?

The eyes look to the Side of the stroke

45

White curvy line on CT head

What is it?

MCA stenosis

46

What is the consequence of blood in the ventricular system?

Like crap in a drain, plugs the drain
CSF can't travel properly

Cause Hydrocephalus

47

There is no gold standard for distinguishing hemorrhagic vx ischemic stroke

Always get CT before TPA

Therefore, in rural settings we do not use TPA
(we don't have all the tools necessary)

48

Clinical Pearl:

Strokes follow an expected path. If they don't, it's not a stroke

49

Patient presents with lower face paralysis on right side.

What is the lesion?

Left CN7 UMN Lesion

50

Patient presents with paralysis on the entire R side of the face

R LMN Lesions

(Upper & Lower face is affected)

51

Praxis vs Apraxia

Praxis:
– Ability to perform a learned/skilled motor sequence

Apraxia:
– loss of praxis with intact comprehension, attention, motivation

52

Ideomotor apraxia

What is it?

How could we test for it?

– commonest form of apraxia
– failure to perform skilled/learned motor sequences on command or to imitation

Screening test:
"show me how you would brush teeth, blow match, etc..."

53

Agnosia

– Inability to process sensory info
– Often there is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss

54

Prosopagnosia

– Loss of face recognition
– usually associated with L hemifield defect due to R. PCA territory infarct

55

Projection Fibres

Projection fibers

2 way traffic between thalamus and cortex

56

Hemorrhagic stroke

What is one of the most common causes?

HTN

causes microaneurysms at basal ganglia, thalamus, pons, cerebellum, deep white matter, brain stem

57

Patient presents with episodes of sudden transient loss of vision in one eye.

What is this?

Tx:

Amaurosis fugax (AF)

painless transient monocular visual loss

Tx: ASA or clopidogrel

NOTE: AF is a recognized forewarning of stroke and requires further investigation to pursue its cause

58

Stroke:
Ischemic vs Hemorrhagic

Which is more likely to have ↓LOC?

↓LOC = Hemorrhagic

Sustained, Normal LOC = Ischemic

59

What defines a HTN Emergency?

Sys > 180
...or...
Dia >110

Elevated BP results in target organ damage

60

How does blood appear on CT?

NCCT
vs
CCT

Non-Contrast CT
• blood = black
• clotted blood = white

Contrast CT
• highlights vessels bright grey

61

Dipyridamole
(Persantine®)

Inhibits thrombus formation when given chronically

Causes vasodilation when given at high doses over a short time.

62

Ictus

What is it?

Fancy term for "event"

63

What are the 4 P's?

­ Parenchyma
­ Pipes
­ Perfusion
­ Penumbra

64

Homonculus

Medial to lateral:
legs, trunk, arms, face

65

"Man in a barrel syndrome"

● can’t move arms away from midline as though stuck in a barrel
● associated with postcentral gyrus region
● This syndrome is a more medial stroke = paralyzes the shoulders

66

We are suspecting stroke

Do we want CT with or without contrast?

We want CT without Contrast. This is fast and can determine presence of acute blood.

Both blood & contrast are bright on CT. This may actually make it more difficult to ID hemorrhage.

Contrast is nephrotoxic and adds no further info regarding stroke in acute setting.

67

Lacune

What is it?

● small strokes that are s subcortical regions
● may present with specific lacunar syndromes or they may be asymptomatic.
● most frequently in the basal ganglia and in the internal capsule, thalamus, corona radiata, and pons.

68

TIA

def

Transient episode of neurological dysfunction caused by a focal brain, spinal cord, or retinal ischemia, WITHOUT acute infarction.

(If Sx resolve, it is a TIA)

69

Ischemic Stroke

def

brain, spinal cord, or retinal cell DEATH attributable to ischemia, based on neuro-pathological, neuroimaging, and/or clinical evidence of PERMANENT injury.

(if Sx resolve, it's a TIA, not a stroke!)

70

Ischemia
...vs...
Infarct

►Ischemia
– absence of blood supply
– angina
– TIA

►Infarct
– DEATH of tissues due to prolonged ischemia
– MI = death of cardiac tissue

71

TIA / Stroke

What could cause it?

►Narrowing of large arteries in neck or head

►Cardioembolic Stroke

►Chronic Small Vessel Ischemic Disease

72

►Cardioembolic Stroke

What is it?

A piece of a thrombus that has broken free and is carried through blood (aka embolus) travels to brain → STROKE

Causes:
– A fib
– A flutter

73

►Chronic Small Vessel Ischemic Disease

Chronic changes to the small vessels in the brain

CT head typically shows hypodensity in the subcortical white matter

74

Anti-platelets
...vs...
Anti-coagulants

►Anti-platelets
• ASA
• Clopidogrel (Plavix)
• Aggrenox (dipyridamole / ASA)

►Anti-coagulants
• Heparin
• Dabigatran (Pradaxa)
• Rivaroxaban (Xaralto)
• Apixiban

75

Lacune

Again ... what is it?

● small strokes that are s subcortical regions
● may present with specific lacunar syndromes or they may be asymptomatic.
● most frequently in the basal ganglia and in the internal capsule, thalamus, corona radiata, and pons.

76

Lacune

What are the 5 classic lacunar stroke Sx?

►Pure motor hemiparesis
(dysartheria hemiparesis)
– Infarct in internal capsule or pons

►Ataxia hemiparesis
– Infarct in pons

►Pure sensory Hemiparises
– Infarct in VPL, internal capsule, corona radiata

►Sensorimotor Stroke
– thalamus & adjacent posterior internal capsule, lateral pons

►Dysarthria clumsy hand
– Infarct in internal capsule or pons

77

Lacune

What are the 3 types of pathology that can be seen?

►Microartheroma
– microscopic atherosclerosis

►Lipohyalinosis
– vessel wall thickening leading to reduction in luminal diameter

►Fibrinoid necrosis
– type of necrosis or tissue death due to accumulation of proteinaceous material in the tissue matrix

78

TIA

What 4 investigations do we want?

24hr Holter

Transthoracic Echocardiogram (TTE)

Fasting Lipids

Fasting Blood Sugar

79

Primary motor cortex
...vs...
Motor association cortex

Fx?

►Primary motor cortex
– initiation of voluntary movement

►Motor association cortex
– coordination of complex movement

80

What is the dentatorubrothalamic tract?

connects the dentate nucleus and the thalamus while sending collaterals to the red nucleus

81

What is the Dentate nucleus?

• cluster of neurons
• appears tooth-like or serrated
• located within the deep white matter of each cerebellar hemisphere
• largest single structure linking the cerebellum to the rest of the brain

The VL/VA nuclei receive motor information from contralateral cerebellum (dentatorubrothalamic tract)

82

What is the most likely cause of loss of vision in the R eye with preserved vision in the L eye?

an occlusion of the R opthalmic artery

83

Which branch of the external carotid artery supplies the submandibular gland?

facial

(we are talking artery here, not nerve!)

84

What does the carotid body receive?

Carotid body receives sympathetic nerves

CN9
• Soltarius (GVA)
• Carotid body contains chemoreceptors & baroreceptors
relays gag sensation from oral pharynx