Stroke

What is a stroke:

• Loss of function that occurs when brain cells are killed by a loss of their blood supply

• The characteristic diagnostic features are:

• Sudden onset of symptoms

• Interruption of blood flow in the brain with symptoms lasting 24 hours or lomger

• Can lead to death

Causes and risk factors:

• Cerebrovascular disorder

• Stroke strikes every 5 mins in the UK

• Risk factors include:

• Hypertension, CVD, diet, high cholesterol and smoking

• More than 400 childhood strokes a year in the UK

• The brain needs high levels of oxygen via red blood cells

• Neurons mostly respire areobically

• Need oxygen to provide energy to neurons

• A deprivation of oxygen means you are unable to survive for more than a few mins

Type of stroke:

• Haemorrhagic:

• Where a weakened blood vessel supplying the brain bursts

• Usually occurs due to cardiovascular anomaly or a long history of hypertension

• Weakened blood vessels:

• Arteriovenous malformations, (AVMs), abnormal development of blood vessels in brain since birth

• Aneurysms:

• Usually develop at branching points of arteries

• Enlarges ‘ballooning’ of the blood vessels which can lead to ruptures

• Subarachnoid haemorrhage leads to bleeding into space around the brain

• Haemorrhagic steoke leads to bleeding in the brain which increases pressure

• Ischaemic:

• Where the blood supply is obstructed due to a clot

• Atherosclerosis is a build up of fatty deposits inside the arteries which blocks blood flow

• Two types of obstructions:

• Cerebral thrombosis, blood clot develops at the fatty plaque within the blood vessel (narrowing)

• Cerebral embolism, part of blood clot breaks loose and enters bloodstream of the brain and vessels are too small to let it pass

• Transient Ischaemic attack:

• (Mini stroke)

• Lasts for a short amount of time, usually a few mins but less thsn 24 hours

• A sign that there is a problem and at high risk of having a stroke

• Temporary blockage cuts off the blood supply to part of the brain however this either dissolves on its own or moves away

• Returns normal blood supply and stroke symptoms dissapear

Symptoms:

• Facial dropping on 1 side, corner of lip or eye may droop

• Might not be able to lift 1 or both arms up due to weakness

• Speech is slurred or jumbled

• Neuronal death of posterior frontal, temporal amd parietal areas usually involve MCA

• If veretebra-basilar arteries are involved then infarct in brain stem, inferior temporal lobe (hippocampus) and occipital lobes

F.A.S.T:

• Face, facial weakness

• Arm, can they raise both arms or hold their arms up

• Speech, can they talk, is it slurred

• Time, time to call for an ambulance or to have intervention

Circle of Willis:

• 3 branches coming off aorta

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