Stroke/TIA Flashcards
Definition of stroke.
“An acute onset of focal neurology deficit or global neurological dysfunction leading to death, or lasting longer than 24 hours as a result of damage to the central nervous system that is vascular in origin”
Definition of TIA.
An acute onset of focal neurology deficit or global neurological dysfunction which resolves within 24hrs with no lasting effect - No death to CNS
What is the largest burden of stroke on the NHS?
The disability care and carers required post-stroke
How many people in the UK have a stroke each year?
152,000
What is the 4th leading cause of death in the UK?
stroke
What is the lifetime risk of having a stroke for men and women?
Men 1 in4
Women 1 in 5
What are the non-modifiable risk factors for stroke?
Age Gender Genes Ethnicity Previous TIA/stroke
What are the modifiable risks for stroke/TIA?
AF high BP high cholesterol vascular disease diabetes heart failure smoking/ recreational drug use physical inactivity/ obesity/ diet Contraceptive pills Thrombophilia OSA
How much of the cardiac output is to the brain?
20%
What is the normal cerebral perfusion rate?
50ml/100g/min
What perfusion rate can the brain compensate to?
about 20ml/100g/min
What perfusion rate does the brain become seriously affected?
10ml/100g/min
Why is the brain so dependent on glucose?
CAnt really respire anaerobically
Does everyone have co-dominant vertebral arteries?
No - one is normally dominant
What is the simplified purpose of the frontal lobe?
higher level cognition
language
Primary motor cortex
What are the simplified functions of the parietal lobe?
Reasoning tactile senses
verbal memory
expressive language
somatosensory cortex
What are the simplified functions of the temporal lobe?
speech perception, interpreting sounds/language
Hippocampus: memory – not often a key defining feature of a lot of stroke
What are the common symptoms of frontal lobe strokes?
Disinhibition Apathy Irritabilty/anger innapropriately Innapropriate placidity Obsessional behaviour Distractability Poor planning skills Utilisation behaviour (see a tool- use it) Release of primitive reflexes (pout, palmomental) Gait apraxia
What are the main catergories of aetiologies of ischaemic stroke?
Carotid disease and verterobasilar disease
Embolic sources
Hypoperfusion
Inflammatory
What are some examples of carotid disease and vertebrobasilar disease?
Carotid stenosis- chronic atherosclerotic disease
Plaque rupture with either thrombosis (causing stenosis/occlusion) or embolism
Dissection- splits the blood vessel, blood flows into the slit instead of the vessel, blocks off vessel or causes thrombus. Typically painful. Usually history of trauma with neck pain and can be associated with Horner’s syndrome.
What are some examples of embolic sources of ischaemic stroke?
AF – static blood will clot
Paradoxical emboli and patent foramen ovale (25% of people have this)
SBE – subacute bacterial endocarditis – bacterial infection in heart, vegetation from growth of bacteria can dislodge
LV thrombus/post MI
Mechanical valves (usually with suboptimal anticoagulation) – metal valve can be traumatic and pro-thrombotic
Post operative carotid/peripheral vascular/valvular/cardiac surgery
Prothrombotic states – antiphospholipid syndrome, polycythaemias and hyperviscosity syndrome, cancer
What are some causes of hypoperfusion?
Sepsis, iatrogenic, hypovolaemia
Starotid stenosis
What is an example of an inflammatory disease that can cause ischaemic stroke?
Vasculitis
What is the aetiology of haemorrhagic stroke?
Rupture of vessels
Through excessive pressure (hypertension)
Or friable/damaged vessels:
Vasculitis
Amyloid angiopathy – blood vessel become weak leading to multiple small haemorrhages, can present similar to TIAs
Vascular malformations – cavernoma (benign vascular tumour) or arteriovenous malformations (generally present with epilepsy
Moyamoya
Trauma eg traumatic SAH
Malignancy – bleed due to abnormal vascular composition – weird to have a large haemorrhage further away from the centre – indicates cancer
What is the danger of blood in the ventricular system?
Blood in ventricular system – clot and block outflows of CSF = hydrocephalus
What is the common presentation of stroke of anterior circulation
Hemiplegia hemisensory loss neglect/ inattention Speech problems – dysarthria is slurred speech due to muscle problems, dysphasia is speech due to brain Amarausis fugax
What are the common presentations of stroke of the posterior circulation?
balance problems visual field defects swallowing problems Poor co-ordination Drowsiness – hypothalamus is key for keeping alert and awake cognitive issues (thalamic involvement)
What is haemorrhagic stroke commonly associated with that ischaemic stroke isnt
headache
drowsiness if a large bleed
What are common focal motor deficits
Patterns of motor weakness and examination
Hemiparesis
Focal single limb/facial weakness, could be proximal or distal, try and note if there is truncal weakness
Pyramidal in pattern (arms flexors>extensors, legs flexors
What are some motor symptoms that can lead to a wrong diagnosis of stroke?
Peripheral nerve distribution of weakness e.g. BELL’S PALSY IS NOT A STROKE SYNDROME. Bell’s palsy is LMN – effects whole face unilaterally, in stroke you generally have innervation to both sides of forehead still intact
Bilateral symptoms
Variable weakness during examination or fatiguability
What are some patterns of sensory loss associated with stroke?
Hemisensory loss Confined to one limb Unilateral Does not cross the midline Generally mutlimodal Look for cortical dysfunction such as stereognosis or graphaesthesia
What patterns of sensory loss could lead to wrong diagnosis of stroke?
Positive sensory phenomena generally do not occur in stroke – more likely to be lower motor neuron disorder
Peripheral nerve distribution
Sensory levels
Bilateral symptoms
What visual defects would a left TACS give you?
right homonymous hemianopia
What visual defect might a left superior parietal infarction give?
right inferior quadrantanopia
What are the symptoms needed to class a stroke as total anterior circulation syndrome or partial anterior circulation syndrome
Total anterior circulation syndrome (TACS)
All 3 of unilateral weakness/sensory deficit, homonymous hemianopia, higher cereberal dysfunction (dysphasia, inattention/neglect)
Partial anterior circulation syndrome (PACS)
Either 2 of the above or higher cerebral dysfunction alone
What are the symptoms needed to classify a stroke as posterior circulation syndrome?
Posterior circulation syndrome (POCS)
Any of: ipsilateral cranial nerve palsy with contralateral motor and/or sensory deficit; bilateral motor and/or sensory deficit; disorder of conjugate eye movement; cerebellar dysfunction; isolated homonymous visual field defect
What symptoms cause a stroke to be classed as a lacuna stroke?
Pure hemi-motor, pure hemi-sensory, pure sensori-motor, ataxic hemiparesis
What method is the classification of strokes based on?
Oxford Classification of stroke
What percentage of strokes are ICH?
10%
How does risk of an ICH alter with age?
It increases:
Incidence >55 yrs increases x2 with each decade
>80 yrs then x25
What are common causes of ICH?
Acute and Chronic hypertension Increased cerebral blood flow: Migraine, exercise, cold Vascular anomalies: AVM, venous angina Arteriopathies: Amyloid - 10% of ICH, Apolipoprotein Ee4 allele/ Down’s syndrome Fibrinoid necrosis, lipohyalinosis, cerebral arteritis Tumours: Coagulation disorders CNS sepsis fungal , granuloma, herpes simplex Venous sinus thrombosis Drugs Cocaine Trauma
What does a AVM ICH look like? What does it cause? Where is it often?
Orange as the haemoglobin has stained it.
Causes epilepsy
Often in middle meningeal area?
What is the presentation of AVM?
Haemorrhage: 40 - 60% Less severe than SAH bleeds Epilepsy Neurological deficit Headache Cranial bruit - audible vascular sound
Should you immediately remove clot from a ICH?
Sucking out a clot will actually often kill the penumbra
Leave the clot in if it can be absorbed naturally, just relieve pressure
Quality of life rather than good surgical skills
What are the GCS guidelines for operating on a ICH?
If GCS of 14+ and the bleed is <4cm then treat medically
If GCS of 13 or lower and the bleed is larger than 4cm then treat surgically
Why is the threshold for operating on a clot that caused ICH lower if it is near the cerebellum?
In the cerebellum - lower threshold for as to operate as increased pressure = hydrocephalus
Describe decompressive craniectomies and why they are needed for ICH
Most intracerebral strokes cause oedema WO mortality is 80% Early intervention is better than late Right side is better than left There are predictors of early brain swelling on CT of more than 50% infarct
What is the most common cause of SAH?
trauma
What occurs in SAH?
Occurs when a blood vessels on the brain surface ruptures:
Aneurysm
Arteriovenous malformation (AVM) - arteries join directly to veins without capillary beds which means the blood moves into the vein quickly, without lowering the pressure from the artery. The veins are thin walled and leak blood.
What is the peak age for SAH?
55-60
What are the most common places for aneurysmal SAH?
85-90% carotid system 5-15% vertebrobasilar system 30% AcommA 25% PcommA 20% MCA
What are the stats of fatality of SAH?
10% die before reaching hospital
Further 8% die before neurosurgical care
7% die with neurosurgery because of spasm
What are the symtpoms of SAH?
Headache Nausea Vomiting Brief LOC Neck stiffness Hemiparesis Vertigo Faintness Confusion
What are 2 main factors that cause deteriation in hospital?
major rebleed
hydrocephalus
What are the risk factors for SAH?
Hypertension Smoking OCP Cocaine - surge of BP Age LP/cerebral angiogram Pregnancy Diurnal variation in BP
What are the disease states associated with intracranial aneurysm formation?
Increased BP Increased blood flow Blood vessel disorders Genetic Congenital Tumours metastatic to cerebral arteries Infectious
What are the non-aneurysmal causes of non-traumatic SAH?
Arterial lesions AV shunts Cardiac myxoma Sickle cell disease Vascularitis Infections Tumours drugs
Descibre the grading of SAH
world federation of neurological societies 0-5. Based on GCS and deficit 0 - normal baseline 1 - GCS 15 2 - GCS 13-14 3 - GCS 13-14 + deficit 4 - GCS 7-12 +/- deficit 5 - GCS 3-6 +/- deficit
4 and 5 are basically dead
What does the fisher grade assess?
The amount of haemhorrage on CT scans - blood loss and severity
Describe the management of SAH
Day 3 - 21: major arteries go into spasm so try to keep BP normal:
Treat with lots of fluids
If you can drop normal osmolarity of blood by 1/3rd increases blood flow and decreases the likelihood of another bleed
Loss of Na+ due to BNP:
Need to monitor fluid and salts to keep level
Vasospasm monitored on angiogram/dopplers
Nimodopine - Blocks calcium dumping at end of apoptosis to keep cells alive:
Doesn’t reverse vasospasm
What is the treatment for SAH from an aneursym?
Radiologist can coil aneurysms- not invasve, has massively overtaken clipping:
Surgeons can clip any aneurysm but requires surgery - can be done with hypothermic circulatory arrest to increase time
Gamma knife treatment - slow to work but works really well in long run to prevent long term problems
What are the complications of SAH?
Rebleeding Hydrocephalus Vasospasm Hyponatremia Infarction
What are the risk factors for vasospasm?
Younger Smoking Hyponatremia Hyperthermia Dehydration Hypotension Hypoxia
What are the advantage of early surgery following stroke?
Prevention of rebleeding Aggressive management of vasospasm Removal of sub arachnoid blood Early ambulation Reduced medical complications Shorter hospital stay Pyschosocial reassurance
What are the disadvantages of early surgery following stroke?
Swollen brain
Unstable patient
Scheduling difficulties
Inexperienced operating team
What are the advantages of delaying surgery following stroke?
Slack brain Stabilised patient Esaier dissection Flexibility in scheduling Experienced operative team
What are the disadvantages of delayed surgery following stroke?
Rebleeding
Delayed ambulation
Longer hospital stay
Psychosocial stress
How is the risk of stroke following a TIA assessed?
ABCDD score
Brain imaging - DW MRI
What ABCDD puts a patient at high risk of having a stroke? What does this result in?
> 4 – high risk, seen in 24 hrs
What ABCDD puts a patient at low risk of having a stroke? What does this result in?
<4 – low risk, seen in clinic within 1 week
Why is diagnosing TIA difficult?
• Diagnosing is difficult: post presentation, relying on history
Variety of symptoms - depends where
What are the high risk TIAs
o Crescendo
o Anti-coagulants
o AF
o Known carotid stenosis
What is emergency treatment for a TIA?
o Aspirin 300mg stat – 75mg od
o If on warfarin – test INR and see if the response is good
o Clopidogrel monotherapy
What is the early secondary prevention for TIA?
o BP, DM, cholesterol, smoking, alcohol, weight, exercise
o Warfarin/DOAC for patients in AF
o Statin
What are amyloid spells?
transient neurological phenomena which leaks small amount of blood onto the surface of the brain
What percent of strokes are ischaemic and of them what percent are the different causes?
85%:
25% large vessel disease
25% small vessel disease
25% cardioembolic stroke
25% other/obscure
What is key for atherosclerois (large vessel disease)?
Inflamamtion
Describe the mechanism of formation of atheroma.
o Thrombus on lesion causing local occlusion
o Embolism of plaque debris or thrombus in distal vessel
o Small vessel origin occlusion by growth of plaque
o Severe reduction in diameter of vessel lumen leads to hypoperfusion and infarction of distal “watershed” areas
Why do you not know about carotid stenosis until you have a TIA/stroke?
the cerebro-automatory mechanisms are too good, not like heart where you get angina
What is indications for carotid endarterecteomy or carotid artery drug eluting stent?
if you see severe carotid stenosis with symptoms
What are the risks of CEA?
3-6% of stroke
Where does a carotid bifurcation emboli usually go?
eye or anterior 2/3rds of cerebral hemisphere
What are some examples of antiplatelet treatments?
Clopidogrel, ticagrelor, aspirin
What is lacunar stroke?
occlusions of small penentrating arteries
What causes lacunar strokes?
• Small vessel arteriopathy -hyaline arteriosclerosis:
o Muscle and elastin in arterial wall replaced by collagen
o Wall thickening with subsequent lumen narrowing
o Diabetes, hypertension, age