Cerebral Infarction (Clinical) Flashcards
What is the global burden of stroke?
5 million stroke deaths each year
2nd leading cause of death worldwide
>15 million non-fatal strokes each year
>50 million stroke/TIA survivors alive
What is the UK stroke burden?
>100,000 new strokes per year
~75% of strokes occur in people > age 65
~1/3 of patients die within 1 year of stroke
1.2 million stroke survivors
50% of survivors remain dependent on others
Stroke accounts for more hospital and nursing home bed-days than any other condition.
Annual cost of stroke £26 billion (set to triple by 2035)
(includes direct health care costs, productivity loses due to mortality and morbidity, and informal care costs)
Stroke Risk _________ with Age
Stroke Risk Increases with Age
It is a disese of ageing
Are all stroke presentations the same?
No all different
depends what area of the brain is affected
What is a stroke?
is the sudden onset of focal or global neurological symptoms caused by ischemia or hemorrhage and lasting more than 24 hours
What are the 2 different types of stroke?
85% are ischaemic strokes
15% haemorrhagic strokes
What is a transient ischemic attack (TIA)?
the term used if the symptoms resolve within 24 hours
Most TIAs resolve within 1-60 min
Ischemic strokes make up 85% of strokes, what are the different types of ischemic strokes?
- Large artery atherosclerosis (e.g. Carotid) 35%
- Cardioembolic (e.g. atrial fibrillation) 25%
- Small artery occlusion (Lacune) 25%
- Undetermined/Cryptogenic 10-15%
- Rare causes <5%
- Arterial dissection
- Venous sinus thrombosis
Haemorrhagic strokes make up 15% of all strokes, what are the different types of haemorrhagic strokes?
- Primary intracerebral hemorrhage 70%
- Secondary hemorrhage 30%
- Subarachnoid hemorrhage
- Arteriovenous malformation
Wht are the 2 different types of risk factors for a stroke?
modifiable
non-modifiable
What are the non-modefiable risk factors for a stroke
Previous stroke
Age
Male
Family history
WHat are modifiable risk factors of a stroke?
the pill
smoking
western diet
obesity
high blood pressure
drugs
lack of exercise
What is the most important modifiable risk factor?
Hypertension
The most important modifiable risk factor
The risk of stroke is related to the level of blood pressure
Chronic hypertension exacerbates atheroma and increases involvement of smaller distal arteries
WHat are small end arteries more at risk of?
Small end arteries coming directly off large arteries experience higher pressure and are at risk of lipohyalinosis causing:
I. Lacunar ischaemic stroke
II. Small vessel haemorrahges
Especially in:
- Brainstem
- Basal ganglia
- Subcortical areas
How does smoking increase the risk of strokes?
·Smokers have:
- 2x increased risk of cerebral infarction
- 3x increased risk for sub-arachnoid hemorrhage
Some of the increased risk relates to the complications of cardiac problems
How does diabetes and lipids affect the risk of a stroke?
Diabetes mellitus increases the incidence of strokes 3x
Hypertension, cigarette smoke, and diabetes contribute to LDL-C deposition in arterial walls
How do lipids relate to the risk of a stroke?
The relationship between serum lipids and stroke is established
Risk related to development of atheroma in blood vessel walls
A high plasma level of low density lipoprotein (LDL) results in excessive amounts of LDL within the arterial wall
How does alcohol increase the risk of stroke?
Complex relationship
Small amounts of alcohol may decrease stroke risk
Heavy drinking increases the risk 2.5 x
How does inactivity and obesity (especially abdominal/thigh) increase the risk of a stroke?
independent risk factor for vascular disease including stroke
How does AF affect a persons risk of a stroke?
Prevalence of AF doubles with age: 9% at 80-90 years
5x increased risk embolic stroke
More severe strokes
Higher mortality and morbidity, longer hospital stays, and lower rates of discharge to patients’ own homes
What is used to help reduce the risk of ischemic strokes?
In patients with AF antiplatelets (e.g. Aspirin) have no benefit in reducing ischaemic stroke
Anticoagulants (warfarin and DOACS) reduce the risk of ischaemic stroke by 2/3rds
DOACS (e.g. Edoxaban and Apixaban) have less risk of causing bleeding than Warfarin
What are some other risk factors of a stroke?
Other cardiac causes (recent heart attack, myxoma, PFO - patent foramen ovale)
Oral contraceptives (+ HRT) with a high estrogen content. Progesterone-only OK
Hyper-coagulable states:
- malignancy
- genetic
What is the arterial circulation to the brain?
Anterior circulation:
2 x Internal carotid arteries
• 2 x Anterior Cerebral Artery (ACA)
• 2 x Middle Cerebral Artery (MCA)
Posterior circulation:
2 Vertebral arteries → 1 basilar
• 3 pairs of cerebellar arteries
• 2 Posterior cerebral arteries (PCA)
What are the anastomoses of the arterial supply to the brain?
Circle of Willis - via anterior + posterior communicating arteries
Borderzone anastomoses - between peripheral branches of anterior, middle and posterior cerebral arteries
image showing blood supply to the brain
The signs and symptoms the patient has should make _____: i.e. fit in with an _________ and an _____ of the brain
The signs and symptoms the patient has should make sense: i.e. fit in with an artery territory and an area of the brain
When making a diagnosis of a stroke, the diagnosis should give you the answers to what questions?
What is the neurological deficit?
Where is the lesion?
What is the lesion?
Why has the lesion occurred?
What are the potential complications and prognosis?
What is the functions of the frontal lobe?
High level cognitive functions ie. abstraction, concentration, reasoning
Memory
Control of voluntary eye movement
Motor control of speech (dominant hemisphere) - expressive dysphasia/Broca’s aphasia, “non fluent aphasia”, Brocas area critical for language pronunciation and production and articulation
Brocas area usually left inferior frontal hemisphere
Motor cortex
Urinary continence
Emotion and personality
What are the functions of the parietal lobe?
Sensory cortex
Sensation (identify modalities of touch, pressure, position)
Awareness of parts of the body
Spatial orientation and visuospatial information (non dominant hemisphere)
Ability to perform learned motor tasks (dominant)
What are the functions of the temporal lobe?
Primary auditory receptive area
Comprehension of speech (dominant) – Wernicke’s
(Wernicke’s aphasia – usually left hemisphere. Deficit in language comprehension. Can speak fluently but has semantic errors and may sound nonsensical/jargon)
Visual, auditory and olfactory perception
Important role in learning, memory and emotional affect
Where deos the anterior and middle cerebral arteries represent on the homonculus and what are the effects of them being blocked?
Does the location of stroke matter?
Yes
a small storke in one place may have dramatic effects
What is the function of the cerebellum?
balance and coordination
What is the brainstem?
Midbrain, pons and medulla
10 of 12 cranial nerves arise in brainstem (ipsilateral signs)
Contralateral hemiparesis due to crossing of cortical tracts in lower medulla
Some major functions: eye movement, breathing, swallowing, heart beat, consciousness
What are the functions of the occipital lobe?
Primary visual cortex
Visual perception
Involuntary smooth eye movement
What are some visual field defects tha can effect visual pathways?
What is the clinical presentation of a stroke?
Sudden onset loss of function:
Motor (clumsy or weak limb)
Sensory (loss of feeling)
Speech: Dysarthria/Dysphasia
Neglect/visuospatial problems
Vision: loss in one eye (amaurosis fugax) or hemianopia
Gaze palsy
Ataxia/vertigo/incoordination/nystagmus
Stroke is a dynamic phenomenon where time is brain
What are important things to remeber in regards to a stroke?
The symptoms come on rapidly
The symptoms depend on which part of the brain is affected
Abnormal movements are unusual after stroke
Positive visual phenomena more likely to be migraine
Severe headache is unusual after stroke
What is the OCSP Stroke Classification of different strokes?
Total Anterior Circulation Stroke (TACS)
Partial Anterior Circulation Stroke (PACS)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
What kind of stroke is A?
LACS
What kind of stroke is B?
PACS
What kind of storke is C?
TACS
What kind of storke is D?
POCS
What is a TACS?
Main artery to one hemisphere
“Full house” of effects 3 of 3:
- Complete hemiparesis/numbness
- Loss of vision on one side (hemianopia)
- Loss of awareness on one side (inattention) non-dominant
or
- Dysphasia dominant
TACS is often due to blocked Carotid or Middle cerebral artery
What is a PACS?
Branch of main artery
In-between LACS and TACS
2 of 3 TACS criteria
or
One higher cortical deficit:
Inattention
Or dysphasia
or
Monoparesis
What is a LACS?
Small “perforating” artery
Movement and sensation pathways
Weakness/numbness of:
Face + arm + leg
Or Face + arm
Or Arm + leg
May have dysarthria
Ataxic hemiparesis
No affect on higher function - Will not have dysphasia, inattention or hemianopia
What is a POCS?
Any posterior artery
Combination of symptoms including:
Loss of balance/coordination
Vertigo
Double vision
Dysarthria - difficult or unclear articulation of speech that is otherwise linguistically normal
Visual loss (hemianopia)
What happens when there is a basilar artery occlusion?
Ischaemia in pons
Predominantly motor/oculomotor signs/symptoms
Bilateral but asymmetrical
Alteration in level of consciousness common - may progress over 12-24hours
May present as reduced responsiveness - ?cause requiring critical care
What is the outcome at 12 months of the different types of srtokes? (mortality and recurrence rate)
What are some storke mimics?
Seizures
Syncope (hypotension)
Sugar (hypo or hyper)
Sepsis (+previous stroke)
Severe migraine
Space occupying lesions
Si-chological (Functional)
Vestibular disorders
Demyelination
Transient global amnesia
Mononeuropathy
What are positive symptoms of a stroke?
excess CNS neurone electrical discharges
visual (eg, flashing lights, zigzags, shapes, lines, objects)
somatosensory (eg, pain, paraesthesia)
motor (eg, jerking limb movements)
What are negative symptoms of a stroke?
Loss or reduction of CNS neurone function
Loss of vision
Loss of sensation
Loss of limb power
What is a migraine aura?
Due to cortical spreading depression
Classical spreading onset
Visual disturbances
geometric (especially zigzag) patterns
positive symptoms (like a kaleidoscope, running water etc)
Can include sensory, motor or speech disturbance
Headache onset can be >1hour after the end of the aura or no headache
>20% of patients with suspected TIA have migraine aura; this is the most common mimic
What is acute vestibular syndrome?
Common, onset can be acute
Can be very disabling
‘True vertigo’ vs unsteadiness vs dizziness
Nystagmus – unidirectional, increases in intensity when patient looks in direction of fast phase
Vomiting
Even an expert taking a careful history may remain uncertain
MRI can be helpful
Acute ischaemic stroke therapies should…
Restore blood supply
Prevent extension of ischemic damage
Protect vulnerable brain tissue
Comparision of storke treatments
Treatment NNT*
IV TPA < 3h 10
IV TPA 3-4.5h 20
Stroke Units 15
Aspirin < 48h 111
Thrombectomy <6h 3-5
*Number needed to treat to prevent 1 death or dependent
TPA = Tissue plasminogen activator is a protein involved in the breakdown of blood clots
How many stroke patients per year in UK* might avoid being ‘dead or dependent’ with each treatment?
Are stroke units beneficial?
Stroke units ↑good outcomes by ~6%
What are the components of a storke unit?
Clinical staff
Stroke nurses
Physiotherapists
Speech and Language therapists
Occupational therapists
Dietician
Psychologist
Orthoptist
Which acute Stroke treatment has the biggest effect on an individual?
1) Aspirin
2) Thrombolysis
3) Thrombolysis and Thrombectomy
4) Stroke unit admission
3
Which Stroke treatment has the biggest effect on all patients?
1) Aspirin
2) Thrombolysis
3) Thrombolysis and Thrombectomy
4) Stroke unit admission
4
What is TPA?
Tissue plasminogen activator is a protein involved in the breakdown of blood clots
What is the sttrict criteria for the use of TPA?
< 4.5 hours from symptom onset
Disabling neurological deficit
Symptoms present > 60 minutes
Consent obtained
What is the exclusion criteria for IV TPA?
Anything that increases the possibility of hemorrhage:
- blood on CT scan
- recent surgery
- recent episodes of bleeding
- coagulation problems
BP >185 systolic or >110 diastolic
Glucose <2.8 or > 22mmol/L
Time is brain: benefit from TPA declines with ______
time
What is a thrombectomy?
the interventional procedure of removing a blood clot (thrombus) from a blood vessel
TIAS to a storke is like how angina is to MI – a ___________
warning sign
10% stroke recurrence within first 2 weeks
Carotid endarterectomy is effective treatment in symptomatic _________________ stenosis
internal carotid artery
Carotid endarterectomy is a surgical procedure to remove a build-up of fatty deposits (plaque), which cause narrowing of a carotid artery
What are investigations done for stroke?
• All/most patients:
- Routine blood tests (FBC, glucose, lipids, ESR…)
- CT or MRI head scan (infarct vs. hemorrhage)
- ECG + Holter (?AF, LVH)
- Carotid doppler ultrasound (?stenosis)
• Some patients:
- Echocardiogram (valves, ASD, VSD, PFO)
- Cerebral angiogram/venogram (vasculitis?)
- Hyper-coagulable blood screen
What is the seocndary prevention for strokes?
Relative risk reduction % :
- Anti-hypertensives >25%
- Anti-platelets 25%
- Lipid lowering agents 25%
- Warfarin for AF 66%
- Carotid endarterectomy NNT of 3
