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)
List some contraindications to thrombolysis.
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 .
What are the different types of aphasia?
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
