Stroke Flashcards
Define stroke.
Stroke is:
- An acute onset
- Neurological deficit
- Of vascular origin
- Lasting >24hrs
It is subdivided into:
- ischaemic stroke (caused by vascular occlusion or stenosis) (87%)
- haemorrhagic stroke (caused by vascular rupture, resulting in intra-parenchymal and/or subarachnoid haemorrhage). (10% and SAH 3%)
What are the risk factors for ischaemic stroke?
Non-modifiable:
- Old age
- FH
Modifiable:
- HTN
- Smoking
- Diabetes
- Dyslipidaemia
- AF
- Comorbid cardiac conditions - valvular disease, congestive HF
- Carotid artery stenosis
- Sickle cell disease
What are the risk factors for haemorrhagic stroke?
- Cerebral amyloid angiopathy (related to dementias)
- Haemophilia
- HTN
- Smoking
- FH e.g. heritable connective tissue disease
- Anticoagulation
- Use of illicit sympathomimetic drugs
- Vascular malformations
- Moyamoya syndrome
Describe the aetiology of ischaemic stroke.
TOAST criteria classify ischaemic stroke according to pathophysiology
Large artery atherosclerosis (usually >50%) - most commonly extracranial carotid or vertebral arteries or less commonly intracranial arteries. A site for thrombus formation which embolises to distal sites.
Cardioembolism e.g. in AF a thrombus forms in heart and embolises to intracranial circulation
Small vessel occlusion (lacunar) - caused by lipid accumulation due to ageing and hypertension
Other causes: vasculitis, arterial dissection, venous thrombosis, hypercoagulable states, SCD, antiphospholipid antibody syndrome.
What is classification of stroke based on vascular territory of infarction?
Bamford classification
- Total anterior circulation infarction
- Partial anterior circulation syndrome
- Lacunar infarction
- Posterior circulation infarction.
TACI(3/3)/PACI(⅔):
- unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- homonymous hemianopia
- higher cognitive dysfunction e.g. dysphasia
POCI:
- Involves vertebrobasilar arteries
- presents with 1 of the following:
- cerebellar or brainstem syndromes
- 2. loss of consciousness
- isolated homonymous hemianopia
- e.g. Cranial nerve syndromes, Horner’s syndrome, Cerebellar syndromes
LACI (involves internal capsule, thalamus, basal ganglia)
- presents with 1 of the following:
- unilateral weakness (and/or sensory deficit) of face and arm, arm and leg or all three.
- pure sensory stroke.
- ataxic hemiparesis
What type of stroke causes cranial nerve deficits and visual field defects?
Posterior circulation stroke
Describe the cortical vascular territories of the brain.
What type of stroke affects face and/or limbs?
Anterior circulation stroke
Describe arm and leg involvement in a MCA and ACA strokes.
MCA - affects arm more than the leg
ACA - affects leg more than the arm
Due to the layout of the motor homunculus in the primary motor cortex.
What are the clinical features of an MCA stroke?
- Contralateral hemiparesis/hemiplegia
- Contralateral sensory loss
- Contralateral homonymous hemianopsia
- Left hemispheric : aphasia (Broca’s)
- Right hemispheric: visual perception deficits including left neglect
Left neglect (R lesion) is more common than right neglect because right hemisphere regulates attention more than left hemisphere so when it is knocked out there is nothing to compensate for left hemisphere in stroke.
What are the different types of aphasia?
What is the pathophysiology of haemorrhagic stroke?
Bleeding into parenchyma causes primary mechanical injury to brain tissue
Expanding haematoma may cause secondary injury due to mass effect, increased ICP and reduced perfusion causing ischaemia or even cerebral herniation
What is the most important part of a history in stroke?
Time of onset (apart from neurological symptoms)
Seconds or minutes and may be preceded by one or more TIA
What are the signs of stroke? Distinguish between ischaemic and haemorrhagic.
Worst at onset
Pointers to haemorrhagic: (unreliable)
- Meningism
- Severe headache
- Coma
Pointers to ischaemia:
- Carotid bruit
- AF
- Past TIA
- IHD
What are the signs and symptoms of cerebral infarcts?
(make up 50%)
Depending on site
- Contralateral sensory loss or hemiplegia
- Initially flaccid (floppy limb)
- Becomes spastic (UMN)
- Dysphasia
- Homonymous hemianopia
- Visuo-spatial deficit
What are the signs and symptoms of brainstem infarcts?
(make up 25%)
Varied
- quadriplegia
- disturbances in gaze and vision
- locked-in syndrome (aware but unable to respond)
What are the signs and symptoms of lacunar infarcts? What are the locations commonly affected?
(make up 25%)
Affect:
- basal ganglia
- internal capsule
- thalamus
- pons
Present with:
- ataxic hemiparesis - dysarthria/clumsy hand
- pure motor or sensorimotor
- pure sensory
Intact cognition/consciousness except in thalamic strokes
CT or MRI for stroke?
Diffusion-weighted MRI is most sensitive for acute infarct
but CT rules out primary haemorrhage
List some contraindications to thrombolysis.
What is the acute management of ischaemic stroke?
Admission to acute stroke unit
Strict supportive management -
- Glucose - 4-11mmol/L
- Oxygen - maintain at 95%
- BP - do not lower in the acute phase unless there is HTN encephalopathy; consider lowering to at least 185/110mmHg in those going for IV thrombolysis
- NBM
Exclude haemorrhage (CT) and confirm stroke then:
- Aspirin 300mg PO/PR ASAP and OD for 2 weeks or until discharge +/- PPI
- Thrombolysis - alteplase - if <4.5hrs since symptom onset. Given by stroke team only.
- +/- Thrombectomy - within 6hrs (up to 24hrs) of SO; for those with a large artery occlusion in proximal anterior circulation (on CT/MRA)
Delayed treatment
- Statin - if TC >3.5mmol/L; 48hrs after acute phase unless already had a statin prescribed
- Anticoagulation for AF - 14 days after acute phase
- Carotid endarterectomy - if non-disabling stroke in carotid territory and occlusion >70% ECST or >50% NASCET
When would you consider thrombectomy?
Otherwise given alone if:
- SO up to 24hrs ago
- Occlusion of proximal anterior circulation
- Potential to salvage brain tissue
NB: thrombectomy can be given in ADDITION to thrombolysis if within 24hrs and there is a proximal POSTERIOR infarct that has hope of tissue salvage with thrombectomy.
What is the management of haemorrhagic stroke?
Stop anticoagulants and antithrombotics
Supportive -
- Glucose - 4-11mmol/L
- BP - consider rapid BP lowering if BP 150-220mmHg and no CI (next card); lower to 140mmHg but by no more than 60mmHg within an hour.
- Oxygen- target of 95%
Neurosurgery referral
Decompressive hemicraniectomy - within 48hrs of symptoms in certain patients
What are contraindications for lowering BP in haemorrhagic stroke? (NICE)
- Tumour, AVM etc causing the stroke
- GCS <6
- Candidate for surgery to evacuate haematoma
- Massive haematoma with poor expected prognosis
Describe management for re-enablement after stroke.
MDT care on a stroke unit is essential –> better patient outcomes
- Formal assessment by SALT to assess swallowing
- Physiotherapy - minimise spasticity
- Avoid early catheterisation - ensure good bladder and bowel function
- Monitor mood - help with depression in patient and carer
- Involve carer/spouse in all aspects
Describe the steps taken for primary and secondary prevention of stroke.
Primary prevention - before any stroke correct:
- HTN
- Hypercholesterolaemia
- Cardiac disease
- Smoking
- Exercise
- Diabetes
- Use lifelong anticoagulation in AF and prosthetic heart valves
Secondary prevention - to prevent further strokes:
- Control above risk factors
- Antiplatelets
- 2 weeks aspirin 300mg
- long term clopidogrel monotherapy OR dipyridamole plus aspirin
Summarise the secondary prevention management of ischaemic stroke.
Antiplatelet agents - aspirin 300mg immediately and for 2 weeks then clopidogrel 75mg OD long-term*
Statin - if cholesterol >3.5mmol/L, delayed 48hrs after stroke
Anti-hypertensives - aim for 130mHg (or 140mmHg if severe carotid stenosis)
Anticoagulation (not if in sinus rhythm) - start anticoagulation at 14days ;
Optimise other risk factors: DM, HTN, OSA, HF, obesity, AF, HRT, stop COCP, SCD, annual flu jab, DVLA.
*MR dipyridamole 200mg BD if aspirin/clopidogrel CI .
How is a patient’s clinical status for thrombectomy assessed?
Modified Rankin scale or National Institutes of Health Stroke Scale - NICE recommend a pre-stroke functional status <3 on the mRS and a score of > 5 on the NIHSS
What is the prognosis with stroke?
- Overall mortality 60,000/yr in UK
- 20% mortality at 1 month then <10%/year
- <40% fully recover
- Drowsiness = poor prognosis
- Avoid pressure ulcers
How do you test for apraxia?
Dressing or copying a clock face
How do you test for agnosia?
Picking out and naming easy objects from a pile
Agnosia = acuity ok, but cannot mime use; guesses are way-out, semantically, and phonetically
How do you test spatial ability?
Copying matchstick patterns
What are the different types of aphasia?
What side is the stroke on?
An 84-year-old right-handed man presents to the emergency department having developed sudden onset unilateral weakness an hour ago. On examination, he is not aphasic (speech is fully intact) but he has homonymous hemianopia. CT shows anterior circulation stroke.
He is right-handed and therefore his speech centre is in the left hemisphere. The patient is not aphasic, and so, the left hemisphere of the brain is intact. He must have had a right-sided stroke which would result in contralateral, left-sided weakness.
What medications are used to control HTN after a stroke?
IV labetalol
IV GTN
What are the signs of a cerebellar stroke?
Vertigo +/- vomiting
Ataxia (i.e. loss of coordination)
Nystagmus
(Holmes) Rebound phenomenon on examination
What kind of VTE prophylaxis is used in stroke?
IPC - intermittent pneumatic compression
What is PICA stroke syndrome?
Lateral medullary syndrome (posterior inferior cerebellar artery) = WALLENBERG’S syndrome
Ipsilateral: facial numbness, ataxia/nystagmus, dysphagia, CN palsy e.g. Horner’s
Contralateral: limb numbness
What is Weber syndrome?
- Ipsilateral CN III palsy
- Contralateral weakness
What does the FAST campaign mean?
- Face - ‘Has their face fallen on one side? Can they smile?’
- Arms - ‘Can they raise both arms and keep them there?’
- Speech - ‘Is their speech slurred?’
- Ttime - ‘Time to call 999 if you see any single one of these signs.’
At the time of writing (August 2019), the DVLA’s guidelines (available at gov.uk) state that ‘homonymous or bitemporal defects … are not usually acceptable for driving’.
He may not drive for the time being and must inform the DVLA who will probably not allow him to drive
The pathology must be on the right side. It may be confined to the visual system and cause no other features, but it may extend into the right parietal lobe causing neglect, or the right frontal lobe causing left-sided weakness. Language problems are almost always due to left-sided brain lesions. Lesions in the cerebral hemispheres do not as a rule cause diplopia.
- Left arm weakness
- Somatosensory neglect
