Physiology: Stroke

Question 1

Describe the characteristics of an UMN lesion. (pyramidial)

Answer 1

Weakness 
Increased Tone - spasticity 
Increased reflexes 
No wasting 
Upgoing plantar (positive Babinski)

Question 2

List the characteristics of a LMN lesion.

Answer 2

Weakness
Muscle Atrophy
Decreased tone
Decreased reflexes
Normal plantar (none or flexion)

Question 3

Name the issues extrapyramidal lesions cause.

Answer 3

Akinesia, rigidity, tremor

Question 4

Name the issues cerebellar lesions cause.

Answer 4

Ataxia
Dysmetria (inability to control distance, speed and ROM)
Nystagmus

Question 5

What would a cortical lesion produce?

Answer 5

UMN + language/perceptual/frontal abnormalities

Question 6

What would a brainstem lesion produce?

Answer 6

UMN + cranial nerve deficits +/- sensory

Question 7

What is a stroke?

Answer 7

Rapidly developing focal (sometimes global) neurological deficit due to a vascular lesion, lasting longer than 24 hours (if patient survives)

Question 8

What is the pathogenesis causing a stroke?

Answer 8

Acute interruption of arterial supply to CNS = cerebral infarction (cell death), irreversible

Question 9

List the components of the FAST acronym.

Answer 9

Facial drooping
Arm weakness
Slurred Speech
Take action - call 111

Question 10

What is a transient ischaemic attack (TIA)?

Answer 10

Focal neurological deficit
Rapid onset - lasts mins to hours but less than 24 hours
Complete recovery
No evidence of infarction
Tend to recur - stroke after TIA more severe

Question 11

Name the two mechanisms causing stroke.

Answer 11

Block - vessel is occluded
Bleed - vessel ruptures and bleeds into brain tissue

Both cause underperfusion of brain

Question 12

Which is the most common type of stroke?

Answer 12

Ischaemia - 80%

Question 13

What does an ischaemic stroke look like on a CT?

Answer 13

Isodense tissue = watery

Question 14

List where a haemorrhagic stroke can occur.

Answer 14

Intracerebral

Subarachnoid

Question 15

What other things can cause stroke?

Answer 15

Infection (with vasospasm)

Profound cerebral hypoperfusion = infarction (e.g. cardiac arrest)

Question 16

List the two mechanisms causing an ischaemic stroke.

Answer 16

Thrombosis (2/3) and embolism (1/3)

Question 17

Where does thrombosis causing ischaemic stroke occur?

Answer 17

Medium sized arteries

Atherosclerosis - usually in the presence of plaque rupture

Question 18

Where does embolism causing stroke occur and what is a risk factor?

Answer 18

From site outside the brain - LA/LV/Carotid
AF is a risk factor
Thrombus moves elsewhere

Question 19

What causes direct neuronal injury in a haemorrhagic stroke?

Answer 19

Decreased perfusion
Pressure effects (swelling)
Vasospasm –> adjacent ischaemia
Neurotoxicity

Question 20

Why does a haemorrhagic stroke have higher early mortality?

Answer 20

Tends to have more global effects

Question 21

Describe the signs and symptoms of a stroke.

Answer 21

Depends on the location of the lesion
Weakness if the most common sign
Usually UMN + localizing signs

Question 22

What are the signs of a stroke in the anterior circulation?

Answer 22

Unilateral weakness
Unilateral sensory loss
Dysphasia 
Sensory inattention
Visual field defect

Question 23

NB: R stroke/L CVA

Answer 23

Stroke = SE of CVA
CVA = cerebrovascular accident taking place in the brain

Question 24

What are signs that a stroke occurred in the posterior circulation?

Answer 24

Unilateral weakness/sensory loss 
Cranial nerve signs 
Nausea and vomiting
Inco-ordination
Diplopia/disconjugate eyes

Question 25

What are the major cortical signs?

Answer 25

Language impairment (dysphasia/aphasia)

• includes reading and writing
• mainly L cortex
• non fluent/expressive aphasia - broca’s area
• fluent/receptive aphasia - wernickes area - superior temporal lobe

Apraxia and Agnosia

• typically R parietal cortex
• Apraxia = inability to process, plan sequence motor takes
• Agnosia - inability to process sensory information - visual and sensory inattention