Strokes Flashcards
what is a stroke?
A brain attack caused by the disturbance of blood supply to the brain. (with rapidly developing clinical symptoms, focal or global, leading to a loss of cerebral function that can only be attributed to vascular origin).
where does stroke rank in the ‘leading cause of death globally’?
second
name as many stroke statistics as you can
- average stay in hospital 28 days but highly variable
- 1 in 5 acute hospital beds occupied by stroke patients
- 25% of strokes occur in people under 65
- In England, 1/6 people will have a stroke in their lifetime
- 20-33% die within 1-3 months
- Single largest cause of adult disability. (300,000 people in England with moderdate to severe disability)
- In the UK almost two thirds of stroke survivors leave hospital with a disability
what does F.A.S.T stand for?
Face (face falls)
Arms (can’t lift there arms up and keep them there)
Speech (is there speech slurred)
Time ( call 999 if any of these occur)
what are the four major types of strokes?
- ischemic
- haemorrhagic
- intracerebral haemorrhage
- subarachnoid haemorrhage
what does TIA stand for?
Transient Ischemia Attack
what is a TIA?
Small clot that is resolved itself within 24 hours (no tissue death) however, have a high risk of a proper stroke thereafter
what is an intracebral haemorrhage ?
- accounts for 10%
- a rupture occurs causing blood to invade the brain tissue going between neurones and glial cells
- this causes extracellular haemoglobin which is highly oxidative inducing cell death via oxidation causing local inflammation.
how common are subarachnoid haemorrhages?
make up 5% of strokes
How does a subarachnoid haemorrhage work?
- blood leaks out into the brain tissue at high pressure
- subarachnoid blood distributes rapidly over the entire brain and penetrates easily into the deeper layers of the cortex within a few hours
- blood released into the subarachnoid space clots almost immediately and disappears ~ 3 days via clot lysis, which starts early after SAH
what does SAH stand for?
Subarachnoid Haemorrhage
What is the SAH mechanism?
- blood leaks out into the brain tissue at high pressure
- subarachnoid blood distributes rapidly over the entire brain and penetrates easily into the deeper layers of the cortex within a few hours
- blood released into the subarachnoid space clots almost immediately and disappears ~ 3 days via clot lysis, which starts early after SAH
What small proportion does the brain make up in body weight?
2.5%
what amount of energy and cardiac output does the brain use?
20% - energy
15% - Cardiac Output
what are typical MCA stroke symptoms?
- arms and facial weaknesses
- speech affected
what is the most common form of stroke?
Lacunar Stroke
what arteries are affected in a lancunar stroke?
Lenticulostriate arteries
name the next three steps through which the blood flows to perfuse the brain starting from the arch of the aorta?
Next,
- common cartoid artery
- vertebral artery
- middle cerebral artery
what is the most common form of stroke?
Lancunar stroke
what does a brain stem stroke affect?
- fibre tracts (eg. spinothalamic tract)
- nuclei (of cranial nerves)
- physiological functions (conciousness and arousal)
what is the brain stem made up of?
- midbrain
- pons
- medulla
what is the stroke syndromes called when 1,2,3 are affected:
1) Medulla
2) Midbrain
3) Pons
1) Wallenbergi syndrome
2) Weber’s syndrome
3) Locked-in syndrome
definition of occlusion
the blockage or closing of a blood vessel or hollow organ
how does a brain stem stroke occur?
an occlusion of a vessel in the posterior circulartion
stroke revolution happens with three major steps which are?
- rapid
- secondary
- delayed
what happens in the rapid stage in stroke evolution?
- O2 depletion
- energy failure
- terminal depolarisation
- ion homeostasis failure
what happens in the secondary stage in stroke evolution?
- excitotoxicity
- SD-like depolarisations
- disturbance of ion homeostasis
what happens in the delayed stage in stroke evolution?
- inflammation
- apoptosis
current treatments for strokes?
- thrombolysis
- antiplatelets
- anticoagulants
- cartoid endarterectomy
- statins
- antihypertensives
- neurosurgery
What does the treatment cartoid endarterectomy entails?
removal of fatty deposits from artery
what does neurosurgery treatment entail?
Remove the blood and repair the burst blood vessels
what is thrombolysis also known as?
‘cloud busting’
how is the clinical outcome measured?
NIHSS (National Institutes of Heaalth Stroke Scale)
what are some modifiable risk factors that can aid/ lead to stroke?
- hypertension
- cholesterol level
- smoking
- physical inactivity
- obesity
- asymptomatic cartoid stenosis
- alcohol consumption
- atrial fibrilation
Name some non-modifiable risk factors
- Older age
- Race (Hispanic, Black)
- Maternal history of stroke
- Sex (males)
- Diabetes
Risk factors increase the propensity to stroke via?
- a change in the structure and function of blood vessels
- a change with the interface with circulating blood (a reduction/ alteration of CBF (cerebral blow flow))
what three changes in structure and function of blood vessels can increase the risk of stroke?
- artherosclerosis
- stiffening of arteries
- narrowing thickening and tortuosity of arterioles and capillaries
what is atheroma ?
An accumulation of intracellular and extracellular lipid in the inner layer of large and medium sized arteries
what is atherosclerosis?
- its a subtype of arteriosclerosis
- other types include the thickening of the walls of arteries and arterioles usually eg. as a result of hypertension or diabetes
what is an aneurysm?
A bulge in a blood vessel caused by a weakness in the blood vessel wall, usually where it brances
From the outside in describe an artery cross-section?
- thick outer wall
- thick inner layer of muscle and elastic fibres
- endothelium
- narrow central lumen through with blood flows
name the two types of cells and give examples that atheromas contain that can critically influence atherogenesis?
- intrinsic vascular wall cells
eg. endothelium smooth muscle cells - inflammatory cells
eg. macrophages, T Lymphocytes, Mast Cells, Cascade -lesion development.
Give some examples of stroke triggers?
- neck trauma
- pregnancy/ postpartum
- systemic infection
- use of drugs
- mental stress
what happens in a stroke trigger?
- exacerbation of vascular inflammation
- activation of the coagulation cascade
name cells and components involved in a stroke
- glia
- neurons
- vascular cells
- matrix components
- blood vessels
what does inflammation fo to an ischemic lesion early on?
it amplifies it
