Stroke Flashcards
What are the two types of stroke?
Haemorrhagic
Occlusive/ ischemic
What is a stroke?
A sudden loss of neurological function by a disruption of blood supply to the brain
The leading cause of death in developing countries
The largest cause of physical disability in developed countries.
Usually a silent condition. Comes on suddenly
What are some risk factors of a stroke?
Hypertension - Haemorrhagic
Diabetes - Occlusive –> damage blood vessels (can lead to atherosclerosis which is closely linked to strokes)
Obesity - Occlusive
Alcohol (>30 units per week)
High cholesterol
Sedentarism
Smoking
Deep vein thrombosis
What is the main aim of clinical treatment?
Limit damage to the brain - may be through surgery and/ or medication.
Optimise recovery
Prevent re-occurence
What is the coronary arterial calcium score?
General marker of atherosclerosis which can predict stroke risk. Procedure that CT can measure calcium of the arteries to check risk of heart attack.
Calcium can accumulate in the plaque. A scan of the blood vessels can identify amount of calcium inside the vessels which relates to the CVD and stroke risk.
Time consuming and expensive. However non-invasive
0 - no evidence of plaque
1-10 - minimal coronary artery plaque
11-100 - mild coronary artery plaque
101-400 - moderate coronary artery plaque
over 400 - extensive coronary artery plaque
What is the mechanism of atherosclerotic plaque formation?
- Damage to endothelial cells
- LDL cholesterol enters the tunica intima
- Macrophages become active and engulf LDL to form foam cells
- Smooth muscle cells integrate from muscle layer into the tunica intima
- Fibrous cap formed –> plaque
The plaque can take years to form.
What are the scores for CAC?
0 - no evidence of plaque
1-10 - minimal coronary artery plaque
11-100 - mild coronary artery plaque
101-400 - moderate coronary artery plaque
over 400 - extensive coronary artery plaque
What is an Indirect Assessment of PAD?
Measuring blood pressure in both arms and ankles to create a ratio.
Can predict calcification risk.
Always taking the higher number from arm, then do with each ankle.
Cheaper and quicker than CAC.
Score:
<0.3 - Critical ischaemia –> low blood flow, could be due to inflammation narrowing the blood vessel, could also be due to plaque build up. Can occur in those with diabetes
0.3 - 05 - Severe
0.5 - 0.95 - Moderate
> 0.95 - Normal
> 1.3 - Calcification of vessel –> build up of plaque that is restricting blood flow to the ankle. Reduced elasticity of blood vessel due to calcium accumulation.
What are some methods of measuring stroke risk?
Coronary artery calcium score
Indirect assessment of PAD
Blood pressure
Measuring lipid levels
What is a Transient Ischaemic Attack?
Sudden onset of neurological symptoms , temporary disruption in the blood supply to part of the brain.
Symptoms are clearly focal, such as speech and visual disturbances, and numbness or weakness in the face, arms and legs.
Lasts for a few minutes to a few hours
Neurological function returns within 24 hours
Can be a warning sign that the patient is at risk of having a full stroke in the future.
1 of the blood vessels becomes blocked, usually by a blood clot thats formed elsewhere in the body has travelled to the blood vessels supplying the brain. Can also be causes by pieces of fatty material or air bubbles.
Some patients may require a carotid endarterectomy to unblock carotid arteries (main blood vessels that supply brain with blood).
Can a stroke be fully recovered from?
It depends on what part of the brain has been effected by having a low supply of oxygen and nutrients. Some neurons cannot be replaced meaning they cannot be recovered and the function they provide may be compromised.
What is a haemorrhagic stroke?
The most serious type
Less common type of stroke, 15% of strokes in the UK are haemorrhagic.
Important to quickly identify site of bleeding as well as cause
Bleeding in the brain must be stopped quickly to prevent brain damage. For small blood vessels that are bleeding, vasoconstrictors can be used to stop the bleeding.
May require surgery.
Has higher mortality rates and higher rates of severe neurological disability in survivors.
Usually caused by rupture if a deep penetrating artery within the brain
Main risk factor is hypertension, especially those with resistant hypertension (not respondent to at least 3 medications)
Build up of atherosclerotic plaque in blood vessels in the brain, or due to thrombus e.g. DVT (movement of plaque from another part of the body)
Why is hypertension linked to strokes?
For haemhorragic strokes, high blood pressure causes blood vessel damage inside the brain making them stiffen and causes blockages.
Small areas of damage develop which can reduce blood flow to the brain.
Can also cause blood clots.
What is resistant hypertension?
Patient’s that have a diagnosis of hypertension that haven’t responded to at least 3 anti-hypertensive medications.
At least 10-15% patients who are on anti-hypertensive drugs do not respond.
More at risk of a stroke
What is an occlusive/ ischaemic stroke?
Less aggressive than haemmorhagic
Caused by a blockage cutting off the blood supply to the brain.
The most common type of stroke.
Can be due to atherosclerotic plaques building up in blood vessels inside the brain. Or movement of plaques from other parts of the body to the brain, e.g from deep vein thrombosis.
