STROKE Flashcards
Neurology 1
Define stroke
CVA/stroke
sudden onset of a focal neurological deficit due to a presumed local disturbance in the blood supply of the brain lasting more than 24 hours
- vascular
- blood carries essential nutrients and oxygen to the brain. Brain cells are damaged/destroyed without blood supply
- acting fast = vital
- stroke destroy 2 mill brain cells per min
stroke disablement
48% hemiparesis/hemiplegia (paralysis of muscles on one side of the body, contralateral to the side of the brain where CVA has occurred)
22% cannot walk
15 - 27% upper limb impairment
24 - 53% assistance with activities of daily living (ADL)
12 - 18% dysphasia (global, expressive or receptive).
5% residual swallow disorder (dysphagia).
32% clinically depressed
33% cognitive impairment
types of stroke
ischaemic - embolus, thrombus in blood supply to brain
Haemorrhagic - ICH - intracerebral haemorrhage -bleeding occuring with the brain itself
SAH - subarachnoid haemorrhage - bleeding within the subarachnoid spae - between arachnoid membrane and pia mater
Ischaemic 85%
Haemorrhagic 15%
Ischaemic stroke
80% of stroke
Obstruction of major cerebral artery - Anterior, Middle, Posterior cerebral arteries
Brainstem stroke - Vertebral / Basilar Arteries
Causes – atheroma (fatty plaque in vessel wall, e.g. atherosclerosis, thrombus (clot), embolus (moving clot), vessel disease (heart / neck)
cerebral artery blocked by embolism
cerebral ischaemia infarction
area of necrosis/ tissue death
Ischaemic stroke consequences depend on…
Collateral blood flow – Circle of Willis attempts to compensate for occlusion of major brain vessels, some blood can be supplied to the affected area by the opening of these collateral channels.
Vulnerability of cells in the affected area – neurones are most vulnerable to ischaemia (deprived of oxygen rich blood), followed by oligodendrocytes, astrocytes and finally endothelial cells.
Severity & Duration of ischaemia – initially autoregulation compensates. When max vasodilation fails to compensate O2 & glucose extraction fractions are increased. When cerebral blood flow drops to approx 50% of normal, electrical activity is suppressed in an attempt to conserve energy.
three cerebral vessels
anterior
middle
posterior
TACI
TACI - Total anterior circulation infarct
17% stroke
Large anterior circulation infarcts with cortical & subcortical involvement.
Poor prognosis, 50% 6month mortality.
PACI
PACI - Partial anterior circulation infarct
34% stroke
More restricted & predominantly cortical infarcts.
More likely to have an early recurrent stroke than other groups.
10% 6-month mortality
POCI
POCI - Posterior circulation infarct
24% stroke
Infarcts associated with vertebrobasilar artery.
Best chance of good functional outcome.
15% 6-month mortality
LACI
LACI - Lacunar infarct
25% CVA
Infarcts confined to deep perforating arteries.
Also infarcts are small in anatomical size, high level of disability associated
7% 6-month mortality
Intracerebral haemorrhage
15% of stroke
History of hypertension / weakening & microaneurysms arterial walls rupture haematoma
May spread to white matter & cause extensive mass lesion. Usually affects deeper structures.
Onset - severe headache / vomiting
Clinical - hemiparesis, hemisensory loss, homonymous hemianopia
Poor prognosis - 50% loss of consciousness (LOC), increased intracranial pressure (ICP)
subarachnoid haemorrhage
3 - 4% - high mortality
Bleeding into subarachnoid space
Causes:
Berry aneurysm in Circle of Willis
Congenital abnormalities - Arteriovenous malformation (AVM)
Hypertension / vascular disease
Clinical - intense headache, vomiting, neck stiffness, loss of consciousness (LOC)
actue medial management
Diagnosis
Medical assessment
Thrombolysis/Aspirin
Thrombectomy (ESCAPE trial)
Prevent complications Pneumonia, depression Post stroke pain syndrome Pressure sores, Falls Swallow assessment 24hr Physiotherapy assessment 24hr
Escape trial
ESCAPE trial Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing CT to recanalization times
Effects of stroke
A stroke causes damage to the brain, which affects how the body works
The effects will depend on the part of the brain affected
Every stroke is different, people who have a stroke are affected in different ways
Risk factors for stroke
Family history Age Prior stroke/Transient Ischaemic attack (TIA) High blood pressure Smoking High cholesterol Sedentary Lifestyle Obesity Carotid artery disease Atrial fibrillation Diabetes Heart disease Excess alcohol intake
Carotid artery disease
build up of plaque in carotid arteries increases the chances of stroke.
This plaque can block the circulation to the brain or a clot can break off and become lodged in the brain, causing a stroke
Risk factors for ICH or SAH
Aneurysm - a localised, blood-filled balloon-like bulge in the wall of a blood vessel.
Arteriovenous malformation (AVM) - an abnormal connection between veins and arteries, usually congenital. This pathology is widely known because of its occurrence in the central nervous system, but can appear in any location.
Hypertension
TIA
Stroke like syndrome - signs and symptoms of stroke are evident & have recovered within 24 hours -‘mini stroke’
Weakness on one side of body + dysphasia
Risk factor modification / Investigations & Nuseals Aspirin (NSA)
TIA vs. mild stroke?
Risk reduction
Through lifestyle modification
Controlling blood pressure
Smoking cessation
Exercise, diet, etc
Through medical management
Antihypertensive medication
Controlling heart disease
Cholesterol reducing medication
early diagnosis
CT brain to exclude haemorrhage in early stages, and direct appropriate intervention
CT has a sensitivity of 50 - 80% in detecting infarcts
Normal CT in about one third cases
Diagnosis of stroke is clinical (WHO)
stroke prevention
public education
primary prevention Risk factors modification – diet, exercise, weight loss, smoking cessation, avoiding alcohol excess, regular checks of BP & cholesterol
Secondary prevention
All of the above & medications
stroke management
Acute
diagnosis
medically stabilise
manage complications
Early rehab
- hospital/ stroke unit
- involvement of MDT
Late rehab
- community rehab
- Primary care
Risk factors : hypertension
Hypertension (High Blood Pressure) - Single greatest risk factor for stroke
Normal BP 120/80mmHg
BP increases with age, changes with exercise state/fitness.
Regular checks
> 135/85mmHg may need medication (beta-blockers, ACE inhibitors, diuretics).
smoking
Smokers - higher risk of developing stroke (2 fold).
Reduces the amount of oxygen in the blood, causing the heart to work harder & allowing blood clots to form more easily.
Smoking also increases the amount of build-up in the arteries, which may block the flow of blood to the brain,
Damages blood vessels, increasing the tendency of blood to clot.
Smoking cessation – RISK OF STROKE DECREASES
cholesterol
High blood cholesterol is a major risk factor for heart disease and stroke.
Buildup of plaque in artery - narrowing Atherosclerosis.
Check cholesterol.
Diet modification.
Medications (statins, aspirin,
niacin)
Normal values <5.2mmol/L
diet
Low in saturated fat, LDL to reduce risk of stroke.
Oily fish contains omega-3 fatty acids (2 portions of fish per week) & HDL.
If high blood pressure - reduce your salt intake (6 grams of salt per day).
Eat more fruit and vegetables (5 portions per day).
exercise and PA
At least 150 minutes of moderate-intensity aerobic physical activity throughout the week or do at least 75 minutes of vigorous-intensity aerobic physical activity throughout the week or an equivalent combination of moderate- and vigorous-intensity activity.
Aerobic activity should be performed in bouts of at least 10 minutes duration.
For additional health benefits, adults should increase their moderate-intensity aerobic physical activity to 300 minutes per week, or engage in 150 minutes of vigorous-intensity aerobic physical activity per week, or an equivalent combination of moderate- and vigorous-intensity activity.
Muscle-strengthening activities should be done involving major muscle groups on 2 or more days a week.
atrial fibrillation
Atrial fibrillation (AF) is a condition involving an irregular heart rhythm, known as an arrhythmia. 7 fold increase in risk of stroke.
The goal for treating AF is to restore the normal, regular rhythm ofthe heart.
Medications (anticoagulants, diuretics).
Use of electrical stimulation (implanted pace-maker).
Alcohol
Alcohol induced cardiac arrhythmias & cardiac wall motion abnormalities.
Predispose to cerebral embolism, induction of hypertension, enhancement of platelet aggregation and activation of the clotting cascade, & reduction of cerebral blood flow by stimulation of cerebral vascular smooth muscle contraction or by altering cerebral metabolism.
Normal limits: 2-3 units woman, 3-4 units man.
diabetes
Diabetes is a risk factor for heart disease & stroke.
Elevated blood glucose levels can cause damage to blood vessels, increasing clotting risk & stroke.
Control of diabetes is an important element in heart disease and stroke prevention.
Controlling blood glucose levels will help minimize plaque buildup.
Normal blood glucose levels: 4.0-5.9mmol/L.
Risk factors
OCP - oral contraception pill increase risk of stroke if any risk factors are present heavy smoker 40+ hypertensive diabetes mellitus obesity
