Stroke Flashcards
How lethal is a stroke (popularity in cause of death)
3rd biggest cause of death
Strokes occur by…
Transient or permanent interruption in cerebral blood supply
Ischaemia - lack of oxygen/glucose
The two types of stroke are…
Ichaemic and haemorrhagic
What are the symptoms of a stroke?
Difficulty talking or understanding words
Severe unexplainable headache
Sudden decreased or blurred vision
Unexplained dizziness or loss of balance
Weakness of the face, arm or leg on ONE SIDE
Loss of feeling or strange feelings on ONE SIDE
More damage occurs as time goes on, TRUE/FALSE?
True
What is the primary cause of cell death in strokes?
Excitotoxicity
What is excitotoxicity?
Excessive release of glutamate
Neurones are ‘excited to death’
Ca overload
How does excitotoxicity happen?
Failure of glucose/oxygen Na-K pump fails Increased K outside and Na inside Depolarisation Increased Ca influx Increased glutamate release (failed glutamate uptake) Increased depolarisation More Ca/Na influx Enzyme activation, free radical production and cell damage/death
Explain how peri-infarct depolarisation causes more excitotoxic death to occur
Neurones in the penumbra repolarise (neurones in core don’t)
Repolarisation uses energy (ATP) which causes energy depletion
Depolarisation
Repeated cycle lasting 6-8 hours
More excitotoxic death
How are strokes treated?
Tissue plasminogen activator (tPA) is the only licensed treatment.
- Restores blood flow, disperses thrombus
- within 3 hours
- Only for ischaemic (thrombotic) stroke
Can also use neuroprotective agents or risk reduction to prevent more strokes from occuring
Other examples of excitotoxicity include:
Domoic acid, kainic acid, BOAA and BMAA poisoning
- have similar structures to glutamate so act on same receptors
BOAA - AMPAr
BMAA - AMPAr & NMDAr
