Stroke - Risk Factors Flashcards
- epidemiology - risk factors - definition - causes
How many stroke deaths each year?
5 million
2nd leading cause of death worldwide
Features to identify if suspecting a stroke:
Facial weakness, arm weakness, speech problems, call 999
Stroke definition:
The sudden onset of focal or global neurological symptoms caused by ischemic or haemorrhage & lasting more than 24hrs
How many are ischemic strokes and how many are hemorrhagic strokes? (%)
85% ischaemic
15% hemorrhagic
What is a Transient Ischemic Attack (TIA)?
It is the term used if the symptoms resolve within 24hrs. (most TIAs resolve within 1-60mins)
What happens in a hemorrhagic stroke?
Blood leaks into brain tissue
What happens in ischemic stroke?
Clot stops blood supply to an area of the brain
Causes of ischemic stroke (5)
- Large artery atherosclerosis e.g. carotid (35%)
- Cardioembolic e.g. atrial fibrilation (25%)
- Small artery occlusion (Lacune) (25%)
- Undetermined/Cryptogenic (10-15%)
- Rare causes - arterial dissection, venous sinos thrombosis (<5%)
Causes of hemorrhagic stroke (2)
- Primary intracerebral hemorrhage (70%)
- Secondary haemorrhage (30%)
- subarachnoid hemorrage
- arteriovenous malformation
Non-modifiable risk factors
- previous stroke
- age
- male
- family history
Modifiable risk factors
- Hypertension
- Smoking
- Diabetes Mellitus
- Lipids
- Atrial Fibrillation
- Alcohol
- Obesity
(others: oral contraceptives)
Hypertension
- Is the most important modifiable risk factor
- Chronic hypertension exacerbates atheroma & increases involvement of smaller distal arteries
Smoking
- 2x increased risk of cerebral infarction
- 3x increased risk for sub-arachnoid haemorrhage
Diabetes Mellitus
- Increased risk 3x
- Contributes to LDL deposition in arterial walls
Lipids
- Development of atheroma in vessel walls
- High plasma level of LDL results in excessive amounts of LDL within arterial wall
