Stroke Flashcards
75% of strokes occur in people of what age?
> 65 years old
Stroke risk increases with age
How many people die within 1 year of a stroke?
1/3
How many stroke survivors remain dependent on others for daily activities?
50%
What is stroke?
The SUDDEN onset of FOCAL or global neurological symptoms caused by ISCHAEMIA or HAEMORRHAGE and lasting more than 24 hours
What percentage of strokes are ischaemic?
85%
What is transient ischaemic attack (TIA)?
The term used if symptoms resolve within 24 hours
Most TIAs resolve within 1-60 min
What are the main causes of Ischaemic stroke?
- Large artery atherosclerosis (e.g. Carotid) 35%
- Cardioembolic (e.g. AF) 25%
- Small artery occlusion (Lacune) 25%
- Undetermined/Cryptogenic (10-15%)
- Rare causes
What are the main causes of Haemorrhagic stroke?
Primary intracerebral haemorrhage 70%
Secondary haemorrhage 30%
- Subarachnoid haemorrhage
- Arteriovenous malformation
Describe hypoxia to the brain
The failure of cerebral blood flow to a part of the brain
Caused by an interuption of the blood supply to the brain
Can be transient (as in TIA)
Results in varying degrees of hypoxia
What can hypoxia do to the brain?
Hypoxia stresses the brain cell metabolism. This is especially important in the ischaemic penumbra
If prolonged the hypoxia -> anoxia (no oxygen)
What does anoxia cause in brain tissue?
Anoxia -> infarction (complete cell death, leading to necrosis). This is a stroke
Apart from infarction how can further damage result during a stroke?
Oedema, depending on the size and location of the stroke
Secondary haemorrhage into the stroke
What are the non-modifiable risk factors for stroke?
Previous stroke
Being old
Being male
Having a horrible family history
What are the modifiable risk factors for a stroke?
HYPERTENSION Smoking Cholesterol Diet High BMI Sedentary lifestyle Alcohol
How is hypertension related to stroke?
Chronic hypertension worsens atheroma and affects small distal arteries
Both stroke and hypertension reach major proportions in the elderly
Hypertension is a major risk factor for haemorrhagic strokes as well
How is diabetes related to stroke?
Diabetes mellitus increases the incidence of strokes up to 3 fold in both sexes
How is smoking related to stroke?
Smokers have:
- 2 fold increase of cerebral infarction
- 3 fold increased risk of sub arachnoid haemorrhage
How are lipids related to stroke?
Increased serum lipids increase stroke risk due to blood vessel wall atheroma
Increased plasma level of LDL results in excessive amounts of LDL within the arterial wall
Hypertension, cigarette smoke and diabetes contribute to LDL-C deposition in arterial walls
How does alcohol relate to stroke?
Small amounts of alcohol decrease stroke risk
Heavy drinking increases risk 2.5 fold
How does obesity relate to stroke?
(especially abdominal)
Recently identified as an independent risk factor for vascular disease including stroke
What other medical risk factors increase likelihood of stroke?
Impaired cardiac function (recent heart attack, AF)
Oral contraceptives (+ HRT) with a high estrogen content. -Progesterone (only ok)
Hyper coagulable states
- Malignancy
- Genetic
What forms the anterior circulation of the brain?
2 internal carotid arteries
- 2 anterior cerebral arteries
- 2 middle cerebral arteries
What forms the posterior circulation of the brain?
2 vertebral arteries -> 1 basilar
- 3 pairs of cerebellar arteries
- 2 posterior cerebral arteries
What are the symptoms of ACA occlusion?
Contra-lateral
- Paralysis of foot and leg
- Sensory loss over foot and leg
- Impairment of gait and stance
