Week 4 Flashcards
Where does most brain blood flow come from?
80% from internal carotid arteries which feed the circle of willis
what brain circulation feeds optic nerves, frontal, parietal and temporal loads?
Anterior circulation
-
What part of brain circulation provides 20% of the supply?
Posterior circulation
What parts of the brain does the basilar arteries feed?
gives off arteries to the cerebellum, brain stem, thalamus, occipital lobe, temporal lobe
what area is responsible for touch, proprioception, pain, itching, tickle, thermal?
Primary somatosensory area
what area is responsible for controlling voluntary muscle contractions?
Primary motor area
what area is responsible for control of sequential contraction of specific muscle eg writing, speaking
Premotor area
what area is responsible for speaking and understanding speech?
Broca’s area
what area is responsible for recognition of shape, colour and movement of visual stimuli
primary visual area
what area is responsible for interpreting the meaning of speech and recognising spoken word
Wernicke’s area
how much of the bodies volume does the brain represent?
2%
how much cardiac output does the brain require?
15-20% of total resting cardiac output to supply needed glucose and O2 for normal metabolism
Define a stroke?
Any disturbance of cerebral function (>24hours) caused by abnormalities of blood vessels
What are the 3 types of stroke
- Hemorrhagic stroke
- Ischaemic stroke (can be thrombotic of embolic clots or hypoperfusion)
- Transient ischaemic attack
WHat are the causes of an ischaemic stroke?
- thrombotic
- embolic
- hypo perfusion
what are the caused of a hameorrhagic stroke?
- intercerebral
- subarachnoid
- extradural
- subdural
what percentage of strokes do ischaemic strokes account for?
85%
what is the most common cause of ischaemic stroke?
atheroscleoris
what are some common sites of ischaemic strokes?
- carotid bifurication
- origin of MCA
- both ends of basilar artery
How quickly does cell death occur with ischaemic stroke?
1.9milli/min
what causes 50% of all haemorrhagic strokes?
hypertension
- accelerates atherosclerosis
- other damaging effects
what are some S&S for Subarachnoid Haemorrhgae?
- sever sudden onset headache
- neck stiffness
- photophobia
- low back pain (due to inflammatory response)
- Nausea & vomitting (increased ICP & Meningeal irritation
- May have altered LOC
- 10-25% suffer siezures
Some people have symptoms up to 10-20 days before rupture
What is GRADE ONE of the 5 grades of subarachnoid hamorrhage?
– Grade I: Mild headache with or without meningeal irritation
What is GRADE TWO of the 5 grades of subarachnoid hamorrhage?
Grade II: Severe headache and a nonfocal examination, with or without mydriasis
What is GRADE THREE of the 5 grades of subarachnoid hamorrhage?
Grade III: Mild alteration in neurologic examination, including mental status
What is GRADE FOUR of the 5 grades of subarachnoid hamorrhage?
Grade IV: Obviously depressed level of consciousness or focal deficit
What is GRADE FIVE of the 5 grades of subarachnoid hamorrhage?
Grade V: Patient either posturing or comatose
what is a TIA?
TIA is a transient episode of cerebral or retinal dysfunction (amaurosis fugax)
• Results from inadequate supply of blood to the brain
• Lasts less than 1 hour
• A stroke warning sign
What are symptoms of a TIA?
– Temporary hemipegia (unilateral weakness)
– Hemiparesis (altered sensation on one side of the body)
– Dysphagia or aphasia (difficulty or inability to speak)
– Visual loss
– Ataxia (altered balance or co-ordination)
– Vertigo
AFter a TIA, what is the liklinhood that a patient will have a stroke?
20%
half of those will occur within 48 hours
If you have a stroke on your right side of your brain ,wjhat symtoms may you show?
– Problems with movement on the left side of the body
– Lack of feeling on the left side of the body
– Trouble thinking clearly, solving problems or
concentrating
– Impulsive behaviour
– Trouble estimating distance, size, position, or shapes
– Decreased facial expression or difficulty maintaining
eye contact
If you have a stroke on your LEFT side of your brain ,wjhat symtoms may you show?
– Problems with movement or no movement on
the right side
– Lack of feeling to the right side of the body
– Trouble speaking, understanding what others
are saying
– Trouble reading, writing or listening
If you have a stroke on your CEREBELLUM of your brain ,wjhat symtoms may you show?
– Dizziness – Loss of balance – Loss of co‐ordination – Slurred speech – Nausea & vomiting
If you have a stroke on your BRAIN STEM of your brain ,wjhat symtoms may you show?
• The brain stem connects the 2 hemispheres
with the spinal chord. As a result a stroke in the
brain stem may affect both sides of the body.
• The brain stem also helps control speech,
swallowing, eye movements, breathing, heart
rate & blood pressure.
• Some of the changes in a brain stem stroke include: – Coma – Total paralysis of both sides of the body – Problems with speech – Problems swallowing – Double vision – Nausea & vomiting – Hiccups
What are some clinical features of a stroke?
- limb weakness or paralysis
- facial paralysis
- sensory loss
- slurred speech (dysarthria)
- Inappropriate or jumbled speech (dysphasia)
- Visual loss (hemianopia)
- Gaze deviation
- Poor balance, unsteady gait (ataxia)
- Difficulty swallowing (dysphagia)
- Double vision (diplopia)
- 80-90% have some motor deficit at stroke onset
What are some stroke mimics?
- Electrolyte disturbances (Na+, K+, Ca2+)
- Hypoglycaemia or hyperglycaemia
- Seizures (absence, post ictal states)
- CNS infections (encephalitis)
- Brain tumour
- Syncope
- Middle ear (vestibular) disorders
- Stress
- Migraine
- Systemic infection (sepsis)
- Intoxication (drugs or alcohol)
- Trauma (subdural haematoma)
What is the national institute of stroke scales?
Used for all patients with a stroke.
Is a tool used to assess 11 elements of neurological impairment.
Originally used as a research tool is now the Gold Standard for stroke measurement.
It measures neurological function and helps to determine stroke severity
what is the criteria for thrombolysis
– Clear onset of ischaemic stroke symptoms within the
preceding 4.5hrs
– Measurable and clinically significant deficit as assessed
by the Medical Registrar in discussion with either the
stroke Physician or the Physician on call.
– Pt’s CT does not show haemorrhage or non‐vascular
cause of stroke.
