Stroke/TIA Flashcards
4 main types of stroke
Transient Ischaemic attack ‘mini stroke’:
– temporary disruption of blood flow and tissue perfusion within the brain
– minor events which usually resolve rapidly
—- symptoms should resolve within 24 hours to be classed as a TIA
– generally the blood supply is restored and the effects of the stroke disappear
– TIA’s can lead to micro-infarctions, where tiny amounts of brain tissue due leaving microscopic infarctions
—- common in older people, and over the time repeated loss of small amounts of neural tissue is cumulative and can lead to dementia (multiple infarction dementia)
– may be a forerunner for a more serious type of stroke
Risk factors:
– atherosclerotic occlusion of the carotid arteries
– atrial fibrillation where rapid uncoordinated contraction of the atria can lead to turbulent blood flow and clots forming, which can travel upwards through the carotid arteries and into the cerebral circulation
Symptoms:
– highly variable depending on the region of the brain affected
– numbness (perhaps down one cheek on the face or an arm or leg)
– visual disturbances (often mistaken for migraine attacks)
– speech may be affected (slurring words or inability to finish a sentence)
Cerebral thrombosis:
– strokes caused by a thrombus that develops in the arteries that are supplying blood to the brain.
Risk factors:
– frequently seen in people suffering with atherosclerosis or clotting disorders
– pregnancy- because the liver produces more clotting factors making the blood hyper coagulable (increased tendency to clot)
– virchow’s triad:
—- hyper coagulable blood (pregnancy or polycythaemia)
—- endothelial injury (damage to lining of blood vessel, (smoking, poorly controlled diabetes etc))
—- circulatory stasis (where blood flow slows and stops, commonly as a result of immobility)
Cerebral embolism:
- most common type of embolic stroke, where a blood clot forms in one part of the body and then travels through the blood to the brain (Can be a severe complication of DVT (RARE))
Nature of emboli:
– embolus- piece of solid material that is freely circulating in the blood
—- most emboli are blood clots which have formed in another region of the body before detaching and becoming mobile
—- some emboli can be pieces of fatty places which have detached from occluded blood vessel (more rare). Can also be fragments of bone
—- the majority of emboli will become trapped in the pulmonary circulation of the lungs leading to a pulmonary embolism
Risk factors:
– common in patients with atrial fibrillation
– also common in people with hyper coagulable blood
Cerebral haemorrhage:
– bleeding in the brain. Can lead to reduced oxygen delivery to the brain and create extra pressure in the brain and kill brain cells
– occurs when a blood vessel ruptures
Causes:
– can result as a result of trauma
Risk factors:
– major risk is hypertension which places the cerebral arteries under increased pressure
—- can cause weakening of arteries in the blood vessels, leading to a ‘bulging out’ of the wall (aneurysm).
—- this aneurysm can become unstable and then eventually burst out
General symptoms of strokes
Confusion, slurring of words
Paralysis of numbness of face
Problems seeing in one or both eyes
Headache
Trouble walking
dizziness
dysphagia
being or feeling sick
FAST (face, arms, speech, time)
Regions of the brain commonly affected by stroke
Any region can be affected by a thromboembolic (ischaemic) (85%) or haemorrhage stroke
– brain stem
– cerebellum
– cerebral cortex (cerebral hemispheres)
Strokes affecting the brain stem
10% of strokes
Made up of- midbrain, pons and medulla oblongata
These areas contain vital autonomic centres:
– cardiac centre
– vasomotor centre
– respiratory centres
If these vital centres are damaged and the patient is not assessed and treated quickly then the chances of survival are low
Locked in syndrome:
– some brain stem strokes cause this, where the pt is aware of what is going on around them but isn’t able to communicate
Symptoms:
– can affect vital things like heartbeat and breathing
Strokes affecting the cerebellum
3-5% of strokes
Cerebellum- plays an important role ensuring balance and coordinated movement, also plays a role in facilitating the highly coordinated facial and pharyngeal muscle contractions necessary for speech
Symptoms:
– usually associated with poor balance and co-ordination
– speech may be affected and slurred
Strokes affecting the cerebral hemispheres
Over 80% of strokes
The affects are contralateral- left hemisphere stroke will affect down the right side and right hemisphere stroke will affect down the left side
Each hemisphere has 4 lobes and the symptoms experiences from the stroke may indicated what location has been affected
4 lobes of cerebral hemispheres
Frontal lobes:
– somatic motor cortex (conscious movement)
- Symptoms:
– hemiplegia (paralysis down 1 side) (left hemiplegia indicated right frontal lobe etc)
Parietal lobes:
– somatosensory cortex (sense of touch)
- Symptoms:
– hemiparasthesia (numbness/lack of sensation down one side)
Occipital lobes:
– visual cortex (vision)
- Symptoms:
– loss of visual activity of blindness
– cortical blindness (blindness that results from CVA)
Temporal lobes:
– auditory cortex (auditory deficits), essential to visual memory and the formation of long term memory
-Symptoms:
– amnesia (long term memory loss)
– personality changes
– significant deafness usually occurs if there is damage to both temporal lobes
Symptoms of a left hemisphere stroke
Right hemiplegia or hemiparasthesia
Speech impairment and difficulty understanding language
Visual problems including inability to see right visual field
Impaired ability to do maths and allays problems
Impaired ability to read and write
