Stroke Flashcards
TIA is
Transient ischaemic attack
Stroke symptoms which resolve completely within 24hrs
Stroke is
A cerebrovascular accident (CVA)
Rapidly developing loss of brain function due to disturbance in blood supply
Stroke requires neurological deficit persisting longer than 24hrs
If it resolves completely before that then it is a TIA
Causes of stroke
80% are ischaemic, may be
- Atherothrombo-embolic (40%) - Small vessel CV disease (20%)
- Systemic hypoperfusion, Venous thrombosis & other (20%)
20% are haemorrhagic, can be
- Intracerebral (15%) - Subarachnoid (5%)
Haemorrhagic strokes can occur in which spaces
Subdural
Subarachnoid
Intracranial
Incidence of stroke
1-1.3 per 100 people in the UK per year
Only 25% in people of working age
Incidence doubles with every decade over 55 and is double in black people
1/4 men and 1/5 women will have had a stroke by 85
Incidence of TIA
Similar to stroke in people younger than 55
Incidence stable from 55-85, thus far fewer than strokes overall
This is due to likelihood of recovery in 24hrs decreasing as age increases
National Mortality of stroke
12% of all deaths in UK, 9% of male and 13% of female
3rd greatest cause of death after cancer and IHD
56,000 people in 1999
Personal mortality of stroke
At 1yr: 33% dead, 22% dependant on care, 45% independent
In survivors: 1/2 hemiparesis, 1/3 depressed, 1/5 unable to walk, 1/5 aphasic
Risk of recurrence: At 1yr 7%, at 5yrs 16% and at 10yrs 25%
Mortality is 3% lower in women
Disease burden of stroke
6% of total healthcare budget
Occupy 1/5 acute hospital beds and 1/4 long term beds
900,000 people are living in the UK with effects of stroke
Changes in stroke mortality
Steep decline in developed countries, 2% per yr
40% drop in UK from 1981 to 2004 and 30% in US from 1995 to 2005
Attributed to risk factor modification
Ageing of population will counter is and keep numbers stable
Risk factors for stroke
Starting with the largest
1. Hypertension 2. Reduced physical activity 3. Waist to hip ratio
4. Cholesterol 5. Smoking 6. Diet risk score
INTERSTROKE study lancet 2010
Hypertension and stroke risk
Accounts for 35-50% of risk
Lowering BP is effective at reducing risk, a population wide lowering of 3-5mmHg would reduce stroke numbers by 40%
Larger reductions are even more effective
Cholesterol and stroke risk
Unclear now important cholesterol is in stroke risk
But statins are very effective at reducing stroke
They may exert effect through other mechanisms, such as improvements in endothelial function
Physical activity and stroke risk
Protective against stroke in both sexes
Multiple possible mechanisms of action
Alcohol and stroke risk
Heavy alcohol consumption is an independent risk factor for stroke
Modest consumption may be protective
Strategies for stroke prevention
High risk individuals - reduce risk factors particularly BP
- increase physical activity
Whole Population - dietary change and reducing salt in food etc
In both cases modify risk factors
Cerebral arteries
Anterior and middle come off the internal carotid artery
Posterior comes from the vertebrobasilar circulation
Connected by circle of Willis
Classification systems for stroke syndromes
Oxfordshire community stroke project classification –> 4 clinical syndromes based on location, which can be either ischaemic (I) or haemorrhagic (H)
TOAST classification –> 5 categories based on underlying pathology
Oxfordshire community stroke classification
TAC - Total anterior circulation PAC - Partial anterior circulation
LAC - Lacunar stroke (Deep brain) POC - Posterior circulation
Four letter is I/H depending on ischaemic or haemorrhagic cause
TOAST classification of stroke aetiology
- Large artery atherosclerosis
- Cardio-embolism
- Small-vessel occlusion (lacunae)
- Stroke of other determined aetiology
- Stroke of undetermined aetiology
Clinical signs that neurological deficit is vascular in origin
If the symptoms are focal and negative with sudden onset which are maximal at onset—> likely a vascular event
If they are non-focal, including positive symptoms with a gradual or progressive onset—> unlikely a vascular event
Non-stroke signs
Fainting, dizziness or syncope Generalised muscle weakness Urinary or faecal incontinence Confusion and disorientation 4-5% of events thought to be stroke are not
Differentials for non-stroke neurological symptoms
Tumours Peripheral neuropathies and MS Hypoglycaemia Complicated migraine Post-Ictal states
Causes of missed strokes
Unusual clinical presentations - hemiballismus (basal ganglia damage causing lack of suppression of unwanted movements)
Fluent aphasias (Wernicke’s)
Aboulia (disorder of diminished motivation due to frontal damage)
Severe co-morbidity or sedation
Intracerebral haemorrhage
Rupture of blood vessels within the brain
30-day mortality 30-55%
May be caused traumatically or by spontaneous rupture
Spontaneous rupture due to vascular changes due to RFs
Small vessel disease, aneurysms or arteriovenous malformation
Locations of Intracerebral haemorrhage
Basal ganglia - 42% Lobar - 40% Cerebellum - 8% Brainstem - 6% Thalamus - 4%
Mortality of Intracerebral haemorrhage
Estimated based on - GCS on presentation (0,1,2)
- volume of haemorrhage over 30ml (0,1)
- any intraventricular haemorrhage (0,1)
- infratentorial origin (0,1)
Score (mortality %): 1(13), 2(26), 3(72), 4(97), 5(100)
Treatment of haemorrhagic stroke
Acutely stabilise and admit to stroke unit/
