STROKE/ TIA

Question 1

what is a stroke

Answer 1

a stroke occurs when an area of the brain is deprived of blood, resulting in poor brain perfusing resulting in cell death. strokes are characterised by dead tissue within the brain.

Question 2

what types of strokes are there

Answer 2

broadly categorised into two main strokes
- ischemic - blood vessel blockage and accounts for 87%, these are fatty deposits that build up in blood vessels or blood clots
- hemorrhagic strokes - occur as a result of a rupture to blood vessels in or around the brain

Question 3

what is a TIA

Answer 3

A TIA is a temporary is a temporary disruption to blood flow and tissue perfusion. classified as symptoms resolve within 24 hours.
commonly involve symptoms of numbness, visual disturbances and sometimes.
- they can lead to microinfarctions

Question 4

what are risk factors of TIAs

Answer 4

• atherosclerotic occlusion of the carotid arteries, these can rupture, detach and travel into the cerebral circulation.
• rapid uncoordinated contraction of the atria
• clots
• older age (dementia)

Question 5

how does atherosclerotic occlusion form and how can this lead to a thrombosis

Answer 5

• Chronic injury to the endothelium of a blood vessel initiates an inflammatory response (smoking toxins, hypertension e.g.)
• monocytes attach to damaged enothelium and squeeze underneath.
• monocytes enlarge to bigger cells called macrophages these accumulate lipid from circulating blood forming fat-laden foam cells.
• this gets hard, reducing the lumen diameter and is often referred to has hardening of the arteries

The fatty plaque lining blood vessels suffering atherosclerotic occlusion can become unstable and rupture through the delicate endothelial layer.
- these can expose supporting collagen fibres that support endothelium triggering thrombosis.

Question 6

what is a cerebral thrombosis

Answer 6

• This type of stroke occurs when a thrombus (blood clot) forms in the cerebral circulation.
• frequently seen in those suffering from atherosclerosis or clotting disorders
• soooo pregnancy is a risk factor

Question 7

what is virchow’s triad and its relation to cerebral thrombosis

Answer 7

Virchow’s triad is a collection of three factors which predispose to thrombosis.
1. hypercoagulable blood
2. endothelial injury
3. circulatory stasis
Virchow’s triad is a collection of three factors that predispose to thrombosis

Question 8

what is a cerebral embolism

Answer 8

An embolus is a piece of solid material that is freely circulating in the blood
most emboli are blood clots that have formed in another region of the body before detaching and becoming mobile. these can be fatty plaques, bone fragments or air bubbles
cerebral emboli is common in those with atrial fibrillation.

Question 9

what is a cerebral haemorrhage

Answer 9

This form of stroke occurs when a blood vessel ruptures
- a major risk factor is hypertension, causing increased pressure on arteries. this can lead to an aneurysm which is a bulging out of the wall. these can become unstable and eventually burst
- often called blood cherrys, often asymptomatic and usually are seen my MRI or CAT scan
- 1 in 20-25 individuals

Question 10

what are astrocytes and the blood-brain barrier and how is this related to cerebral hemorrhage

Answer 10

• Astrocytes, a type of neuroglial cells, envelop the smaller blood vessels in the cerebral circulation.
• Astrocytes have thin cytoplasmic processes that wrap around the vessel walls, forming the blood-brain barrier (BBB).
  = The BBB prevents metabolic and environmental toxins, as well as blood-borne pathogens, from reaching the active neurons in the brain.
• In the event of a cerebral haemorrhage, the BBB is breached, allowing toxic materials from the blood to directly damage neural tissue.
• Leaked blood acts as a toxic slurry, causing widespread damage to the brain.
• Cerebral haemorrhage can lead to the rapid formation of blood clots (thrombosis), increasing intracranial pressure.
• Increased pressure can compress blood vessels, restrict cerebral blood flow, and cause further tissue damage

Question 11

what areas of the brain are most affected and the S/S of stokes?

Answer 11

brain stem = 10% - vital autonomic centres of the brain e.g. cardiac centre. survical rate low

cerebellum = 3-5% - balance and co-ordinated movement and speech muscles

cerebral hemispheres = 80% - hemispheres are contralateral, controlling opposite sides.
- frontal - somatic motor cortex
- parietal - somatosensory cortex
- occipital - visual cortex
- temporal lobes - auditory cortex

Question 12

what is the difference with left and right hemisphere strokes

Answer 12

Left Hemisphere Stroke:

-Right weakness/paralysis
-Speech and language problems
-Vision issues (right visual field)
-Math and problem-solving difficulties
-Reading and writing impairments

Right Hemisphere Stroke:
-Left weakness/paralysis
-Vision issues (left visual field)
-Judging distances
-Left neglect
-Simplification in tasks (drawing, etc.)

Question 13

how does atherosclerotic occlusion form

Answer 13

• Chronic injury to the endothelium of a blood vessel initiates an inflammatory response
• monocytes attach to damaged enothelium and squeeze underneath.
• monocytes enlarge to bigger cells called macrophages these accumulate lipid from circulating blood forming fat-laden foam cells.
• this gets hard, reducing the lumen diameter and is often referred to has hardening of the arteries