Stroke - pathology + clinical Flashcards
Risk factors of stroke
- modifiable (7)
- non-modifiable (4)
Hypertension Atrial fibrillation - BIG RF FOR EMBOLIC STROKES Recent MI Smoking Alcohol Hyperlipidaemia Diabetes
Old age
Male
Race
Family history of stroke
Define stroke
focal neurological deficit caused by ischaemia or haemorrhage and lasting more than 24 hours
Define TIA
transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia lasting <24 hrs, usually resolve within an hour
Causes of ischaemic stroke (4)
Atherosclerosis
Thromboembolism (e.g. from LA/LV)
Small artery occlusion (lacunar stroke)
Rare causes – venous sinus thrombosis
Causes of haemorrhage stroke (2)
Ruptured aneurysm of a cerebral vessel –> primary haemorrhage
Secondary haemorrhage e.g. subarachnoid haemorrhage
General symptoms/signs of stroke (5)
Vision loss
Unilateral weakness or paralysis of face/arm/leg (hemiparesis/hemiplegia)
Unilateral sensory deficit/loss
Aphasia (impaired expression/comprehension of speech)
Ataxia (impaired co-ordination and speech)
Symptoms/signs of ACA occlusion stroke (think about the homunculus and what ACA supplies) (4)
- what’s more affected - face/arm/leg (may be more than 1)
- which side affected - contralateral/ipsilateral
- speech
- co-ordination
- vision
Contralateral:
- Weakness/paralysis of esp LEG/face (hemiparesis/plegia)
- Sensory loss of esp LEG/face
Aphasia - more likely if left MCA affected as that’s where Broca’s and wernicke’s is
Ataxia (–> impaired gait)
Homonymous hemianopia
Symptoms/signs of MCA occlusion stroke (think about the homunculus and what ACA supplies) (6)
- what’s more affected - face/arm/leg (may be more than 1)
- which side affected - contralateral/ipsilateral
- vision
- speech
Contralateral:
- Weakness/paralysis of esp face/ARM (hemiparesis/plegia)
- Sensory loss of esp face/ARM
Homonymous hemianopia
Gaze paralysis to weak side
Aphasia (unable to understand + produce speech) - more likely if LEFT MCA AFFECTED as that’s where Broca’s and wernicke’s is
Unilateral neglect/agnosia - if RIGHT MCA affected
Symptoms/signs of a right hemisphere stroke (3)
Left hemiplegia Homonymous hemianopia Agnosias (neglect syndromes) -visual agnosia -sensory agnosia
Name the 4 stroke subtypes
Total anterior circulation stroke (TACS)
Partial anterior circulation stroke (PACS)
Lacunar stroke (LACS)
Posterior circulation stroke (POCS)
Common sites of lacunar stroke (3)
Basal ganglia
Brainstem
Cerebellum
ACA occlusion would cause stroke of what surface of the cerebral hemispheres
MEDIAL
MCA occlusion would cause stroke of what surface of the cerebral hemispheres
Lateral
What supplies the basal ganglia
Small end arteries of the MCA
Occlusion of what arteries causes lacunar strokes
Small end arteries of the MCA
Clinical features of lacunar strokes (LACS) (3)
Motor weakness of ≥2/3 of face/arm/leg AND/OR sensory loss of ≥2/3 of face/arm/leg
No hemianopia/dysphasia
No brainstem/cerebellar signs
Name the 4 types of lacunar strokes
Pure motor (commonest) - unilateral paralysis or weakness of ≥2/3 of face/arm/leg
Pure sensory - sensory loss of ≥2/3 of face/arm/leg
Sensorimotor - combo of above
Ataxis hemiparesis
Clinical features of total anterior circulation strokes (TACS) (4)
Motor weakness of ≥2/3 of face/arm/leg AND/OR sensory loss of ≥2/3 of face/arm/leg
Hemianopia
+ ≥1/2 of dysphasia or neglect
No brainstem/cerebellar signs
Clinical features of partial anterior circulation strokes (PACS) (3)
-very similar to TACS
Motor weakness of ≥2/3 of face/arm/leg AND/OR sensory loss of ≥2/3 of face/arm/leg
1 of hemianopia/dysphasia/neglect
No brainstem/cerebellar signs
Clinical features of posterior circulation strokes (POCS) (4)
May/may not have motor weakness of ≥2/3 of face/arm/leg
May/may not sensory loss of ≥2/3 of face/arm/leg
May/may not have any of hemianopia/dysphasia/neglect
Brainstem/cerebellar signs - usually have this but some may not
Signs of POCS (6)
Vertigo Nausea Vomiting Ataxia - esp fine motor co-ordination and gait if POCS Coma Diplopia
Investigations of stroke
- imaging (3)
- bloods (5)
- other (2)
CT - better at showing haemorrhagic stroke
MRI - better at showing ischaemic stroke
CT angiogram - identifies arterial occlusion (e.g. thrombus) or stenosis
Serum glucose - to exclude hypo/hyperglycaemia
U+Es - to exclude electrolyte disturbance
Cardiac enzymes - may be raised if concomitant with MI
FBC - to detect any contraindications to acute stroke treatment like anaemia
Lipids
ECG - to check for arrhythmia
Carotid Doppler
Acute treatment of ischaemic stroke (4)
Thrombolysis (give within 4.5 hours) - IV tPA (tissue plasminogen activator) or alteplase (recombinant tPA)
Emergency thrombectomy - for severe large ischaemic strokes; not done that often
300mg aspirin (24 hrs after thrombolysis)
+/- venous thromboembolism prophylaxis - with anticoagulant (heparin) if have higher risk of clotting, e.g. if have AF
Secondary prevention of ischaemic stroke (5)
- medical (4)
- surgical
Antiplatelets - clopidogrel/aspirin (reduce form 300 to 75mg)
Statins
Anti-hypertensives - thiazide diuretics, ACEI, CCBs
Anticoagulants (if have AF) - warfarin
Carotid endarterectomy - correcting stenosis of the carotid arteries
Contra-indications to thrombolysis (7)
Recent/CURRENT brain haemorrhage
Brain mass/tumour
Recent ischaemic stroke within 3 months
Recent neurosurgery within 3 months
Bleeding diathesis - very vulnerable to bleeding
Recent head trauma within 3 months
Uncontrolled hypertension - systolic >185 or diastolic >110
Criteria for thrombolysis (2)
Symptom onset <4.5 hrs (CANNOT BE DONE AFTER 4.5 HOURS OF PRESENTATION)
Disabling neurological deficit
Acute treatment of haemorrhagic stroke
- supportive care (4)
- medical (2)
- surgical (1)
Immediate emergency care is crucial - focusing on controlling the bleeding in brain and reducing the pressure caused by the bleeding:
Supportive care - oxygen, intubation (if unconsciousness), fluids, feeding
BP control (to prevent further bleeding) - labetalol
DVT prophylaxis - heparin
Emergency craniotomy occasionally - to remove any clots
Stroke differentials (4)
Hypoglycaemia
TIA
Seizure + post-ictal deficits
Brain tumour
What is the penumbra
area surrounding an ischaemic event - flow and therefore oxygen transport is reduced locally, leading to hypoxia of the cells near the location of the original insult
List the main blood vessels in the brain (5)
Vertebral arteries Basilar artery PCA MCA (Arising from ICA) ACA (Arising from ICA)
Main veins/venous sinuses in the brain (4)
Superior saggital sinus
Transverse sinus
Sigmoid sinus
IJV
2 broad categories of cerebrovascular disease
- Focal or localised interrupted blood supply or hypoxia
2. Generalised problem with blood supply or hypoxia
Transient symptoms are due to what
Reversible ischaemia = brain tissue still viable
Longstanding symptoms (i.e. not transient) due to what
Irreversible ischaemia –> localised brain death = INFARCT
Interruption of blood supply is due to changes in what triad
Virchow’s
What is Virchow’s triad + what 3 things does it consist of
3 factors that cause thrombosis
Changes in vessel wall
Changes in pattern of blood flow
Changes in blood constituents
Name 2 causes of a change in vessel wall (part of Virchow’s triad)
Atheroma
Vasculitis
Causes of changes in pattern of blood flow (part of Virchow’s triad)
- stagnant flow (2)
- turbulent flow (2)
Stagnant blood flow:
On planes
Post op/inactivity
Turbulent blood flow:
Atheroma
Aneurysm
Causes of changes in blood constituents (part of Virchow’s triad) (3)
Hypercoagulability
- pregnancy (Acquired) –> above
- cancer (acquired)
- thrombophilia (inherited)
Thrombosis is often superimposed on what
Atheromas
Causative factors of thrombosis (4)
Atheroma
Stagnant flow - inactivity
Turbulent flow - atheroma
Hypercoagulability - pregnancy, cancer, thrombophilia
Causative factor of parenchymal haemorrhage into the brain
Ruptured aneurysm
3 main causes of localised interrupted blood supply which lead to stroke
Atheroma + superimposed thrombosis –> ischaemia
Thromboemoblism –> ischaemia
Ruptured aneurysm –> haemorrhage
Atheromas that commonly cause ischaemic strokes are located where
Bifurcation of the carotid artery
Thrombosis (blood clot) is made of what 2 things
Platelets + fibrin
Thrombosis in the ICA typically leads to ischaemia of which cerebral artery
MCA
Thromboembolism in the carotid arteries commonly comes from where + what other place
LA
LV
Why do thromboemboli commonly come from the LA
Because the left atrial appendage (auricle) is a reservoir of stagnant blood so the blood is more likely to thrombose
How do emboli from the LA or LV get to the carotid arteries
Travel up the ascending aorta and up the carotids
Are cerebral artery walls thick or thin + why
Thin
Because little smooth muscle so don’t constrict/expand much as we don’t want the brain to respond to small things that change BP like caffeine
Cerebral vessels don’t handle … well
+ what does this do to the vessels
+ what can then form from this
Hypertension
Weakens and stretches the wall –> aneurysm formation
2 common sites of ruptured aneurysm (i.e. common sites of haemorrhage strokes)
Basal ganglia
Circle of willis
What type of aneurysms form in the basal ganglia
Microaneurysms
What type of aneurysms form in the circle of willis vessels
Berry aneurysms (look like a berry)
Most common type of aneurysm
Berry aneurysm
3 main causes of generalised interrupted blood supply
Low blood O2,
Lack of blood supply,
Inability to use O2 - RARE, e.g. cyanide poisoning
Causes of low blood O2 (2)
CO2 poisoning
Resp arrest
Name 3 causes of lack of blood supply
Hypotension
Cardiac arrest
Brain swelling (Trauma)
What are watershed areas
When area A supplied by a an artery different from area B meet
Pure hypotension but still with oxygenated blood leads to what kind of infarctions
Watershed infarcts
Name a cause of inability to use O2
Cyanide poisoning
2 causes of ischaemic strokes
Atheroma + thrombosis
Thromboembolism
Cause of haemorrhage strokes
Ruptured aneurysm of a cerebral vessel
Ischaemia =
Lack of blood flow
Hypoxia =
Lack of oxygen
Anoxia =
Complete absence of oxygen
Ischaemia leads to what
Hypoxia
Pathological appearance of an ischaemic stroke due to atheroma/thromboembolsim (5)
- shape
- texture
- colour
Wedge shaped Soft and cystic like Yellow discolouration from foamy macrophages Gliosis (Scarring) Congested swollen vessels
Pathological appearance of an ischaemic stroke due to hypotension (1)
Symmetrical watershed infarcts
Pathological appearance of an ischaemic stroke due to cardiac arrest (2)
Grey matter thinning/necrosis
Laminar necrosis of cortical ribbon (i.e. necrosis of the line of grey matter lining the brain)
Pathological appearance of a haemorrhage stroke
Large area of old, black blood
To be diagnosed as a LACS, patient must be presenting with one of following (3)
Unilateral weakness and/or sensory deficit of ≥2/3 of face/arm/leg
Pure sensory stroke
Ataxic hemiparesis
To be diagnosed as a TACS, patient must have all 3 of the following
Unilateral weakness and/or sensory deficit of face, arm and leg
Homonymous hemianopia
Higher cerebral dysfunction (dysphasia, visuospatial disorder)
To be diagnosed as a PACS, patient must have 2 of the following 3
Unilateral weakness and/or sensory deficit of face, arm and leg
Homonymous hemianopia
Higher cerebral dysfunction (dysphasia, visuospatial disorder)
To be diagnosed as a POCS, patient must have 1 of the following 3
Cerebellar or brainstem syndrome
Loss of consciousness
Isolated homonymous hemianopia
INITIAL investigations of stroke
- bloods (5)
- imaging (1)
- other
Bloods
- FBC
- glucose
- cardiac enzymes
- U+Es
- lipids
CT head
Carotid doppler
ECG
ACA supplies primarily motor output from brain to what extremity
MCA supplies primarily motor output from brain to what extremity
ACA - leg
MCA - arm
