Intro to stroke 1 - epidemiology, definition, neuroanatomy

Question 1

prevalence of stroke globally

Answer 1

5 million deaths
2nd leading cause of death worldwide
>15 million non-fatal/year
>50 million survivors alive

Question 2

uk stroke burden

Answer 2

> 100,000 new strokes/year
1 every 5 mins
1.2 million survivors
annual cost £26bn

Question 3

epidemiology of strokes/TIA

Answer 3

75% in the >65yrs
1/3 patents die within a year
50% survivors remain dependent on others

Question 4

what is the definition of a stroke

Answer 4

“RAPIDLY developing clinical signs of FOCAL (or global) disturbance of cerebral function, with symptoms lasting 24 hrs or longer, or leading to death with no apparent cause other than vascular”

Question 5

what is the definition of a TIA

Answer 5

“Brief episode of neurological dysfunction caused by focal brain or retinal ischaemia, with clinical symptoms typically lasting less than one-hour and WITHOUT EVIDENCE OF ACUTE INFARCTION”

Question 6

how long to TIA’s generally last

Answer 6

majority resolve within 60mins
2/3 resolve in 10 mins

less than 15% chance of complete resolution of symptoms if lasts >1hr

Question 7

what are the types of stroke and how common are each

Answer 7

Ischaemic - 85%
(clot stops blood supply)

Haemorrhagic - 15%
(blood leaks into brain tissue)
- 70% primary ICH
- 30% secondary eg SAH, AVM

Question 8

what are some causes of strokes

Answer 8

cardioembolic

• atrial fibrillation
• valve disease
• left ventricle thrombi
• cardiogenic emboli (25%)

large vessel disease

• carotid plaque with arteriogenic emboli (35%)
• aortic arch plaque
• flow reducing carotid stenosis
• carotid dissection (<5%)

lacunar blood vessel disease

• penetrating artery disease (lacunar strokes - 25%)
• intracranial atherosclerosis
• cryptogenic/undetermined (10-15%)

Question 9

what questions must you ask when diagnosing a stroke

Answer 9

what is the neurological deficit?
where is the lesion?
what is the lesion?
why has the lesion occurred?
what are potential complications/prognosis?

Question 10

in general terms what is the blood supply to the brain

Answer 10

carotid system - hemispheres and cortical deep white matter

vertebra-basilar system - brain stem, cerebellum and occipital lobes

Question 11

what are the functions of the frontal lobe

Answer 11

high level cognition (eg reasoning, concentration, abstraction)
memory
voluntary eye movement 
motor control of speech (brocas)
motor cortex
urinary continence
emotion and personality

Question 12

what is Broca’s area and what happens in damage occurs here

Answer 12

area found in the dominant inferior frontal lobe hemisphere
critical for language pronunciation and production and articulation

damage here can lead to expressive dysphasia/brocas aphasia - a “non-fluent aphasia”

Question 13

what are the functions of the parietal lobe

Answer 13

sensory cortex
sensation (touch, pressure, positions)
awareness of parts of the body
spatial orientation/visuospational information (non-dominant hemisphere)
learned motor tasks (dominant hemisphere)

Question 14

what are the functions of the temporal lobe

Answer 14

primary auditory receptive area
comprehension of speech (wernickes)
casual, auditory, olfactory perception
important in leaning, memory and emotional affect

Question 15

what is wernickes area and what happens if damage occurs here

Answer 15

area found in the dominant side of the temporal lobe - important in comprehension of speech

damage can lead to wernickes aphasia - deficit in language comprehension - can speak fluently but has semantic errors, may sound nonsensical/jargon

Question 16

precentral gyrus

Answer 16

motor map homonculus

Question 17

postcentral gyrus

Answer 17

sensory map homunculus

Question 18

what are the functions of the occipital lobe

Answer 18

primary visual cortex
visual perception
involuntary smooth eye movement

Question 19

what are the functions of the cerebellum

Answer 19

balance and coordination

Question 20

describe breifly the visual pathway

Answer 20

visual field
eye
optic nerve
optic chiasm (swap sides)
optic tract
lateral geniculate nucleus
visual cortex

Question 21

what comprises the brainstem and what arise from here

Answer 21

midbrain
pons
medulla

10 of the 12 cranial nerves arise here (ipsilateral signs)

Question 22

would damage to the brain stem result in ipsi or contralateral signs

Answer 22

contralateral hemiparesis due to crossing of the cortical tracts in the lower medulla

Question 23

what are the major functions of the brainstem

Answer 23

eye movement 
breathing
swallowing
heart beat
consciousness

Question 24

three main points for stroke

Answer 24

1. sudden onset - acute
2. neurological deficit - focal
3. non-traumatic vascular origin