Stroke Flashcards
Define stroke
The damage or killing of brain cells starved of oxygen as a result of the blood supply to part of the brain being cut off.
Infarction or bleeding into the brain manifests with sudden onset focal CNS signs
What is a TIA?
Transient ischaemic attack - a stroke that recovers within 24 hours from the onset of symptoms
What is a stroke syndrome?
Constellation of signs and symptoms produced due to occlusion or damage of an artery supplying part of the brain
What percentage of strokes are ischaemic?
85%
What percentage of strokes are haemorrhagic?
10%
What are the 5 subtypes of ischaemic stroke? (Toast classification)
Large artery atherosclerosis (thrombus or embolus) Small artery strokes (lacunae) Cardioemoblic Other determined pathology Undetermined
What are some stroke risk factors?
HTN Diabetes Hyperlipidaemia Heart disease - AF, valvular heart disease, PVD Smoking Alcohol Cocaine Age esp over 55 Haematological disorders - multiple myeloma, sickle cell disease, polycythemia Vera COCP Increased homocysteine
What does the anterior cerebral artery supply?
The medial frontal and parietal area of brain
Anterior corpus collosum
How would a stroke involving the anterior cerebral artery present?
Contralateral hemiparesis of lower limb - initially flaccid paralysis then spasticity -> UMN signs
Incontinence (damage to paracentral lobule x suppresses micturition)
Contralateral loss of all sensory modalities in lower limb
Inability to understand and/ or produce speech (left hemisphere)
What does the middle cerebral artery supply?
Lateral frontal, parietal and superior temporal part of brain
Deeper branches- basal ganglia, internal capsule, macular cortex
How would a stroke involving the middle cerebral artery present?
Contralateral paresis - upper limb and face. If proximal occlusion: internal capsule also affected (carries descending motor fibres) so leg may also be affected
Contralateral loss of all sensory modalities upper limb and face
Vision: proximal - contralateral homonymous hemianopia, distal - contralateral homonymous superior or inferior quadrantinopia
Speech: depends on dominant hemisphere and which branch of MCA occluded. If dominant hemisphere (most likely left) affected: global aphasia - main trunk occlusion. OR Broca’s expressive aphasia or Wernicke’s receptive aphasia
If non dominant (likely right) side affected:
- hemispatial neglect
- tactile extinction
- visual extinction
- anosognosia
Main trunk occlusion of MCA can cause considerable cerebral oedema and raised intracranial pressure. What term is used to describe this?
Malignant MCA
Decompressive hemicraniotomy needed
What does the posterior cerebral artery supply?
Inferior temporal and occipital region
How would a stroke involving the posterior cerebral artery present?
Contralateral homonymous hemianopia with macular sparing
What do the cerebellar arteries supply?
Cerebellum and brainstem
What signs can be seen as a result of a cerebellar stroke?
Dysdiadochokinesia Ataxia Nystagmus Intention tremor Slurred speech (staccato) Hypotonia (more subtle than LMN lesion)
Due to the cerebellar arteries also supplying the brainstem, what signs can be see as a result of a proximal occlusion?
Cerebellar signs
Brainstem signs - crossed deficits
-> damage to ascending/ descending tracts affects contralateral side, damage to CNS or their nuclei gives ipsilateral signs
What do the lenticulostriate arteries supply?
Internal capsule (posterior limb carries descending motor fibres)
A stroke involving the lenticulostriate arteries would cause…
Contralateral motor hemiparesis
What does the thalamoperforator artery supply?
Part of the thalamus
What are some stroke mimics?
Hypoglycaemia
Epilepsy - post ictal
Migraine (hemiplegic)
Intracranial tumours/ infections
Are the signs of a stroke sudden in onset or do they occur over a long time?
Sudden in onset
What are some haemorrhagic pointers?
Meningism Severe headache Decrease in level of consciousness Nausea and vomiting Seizure
What are some ischaemic pointers?
Carotid bruit
AF
Past TIA
IHD
What imaging needs to be done to rule out haemorrhagic stroke?
CT scan
Once haemorrhagic stroke is excluded, what medication should be given?
Aspirin 300mg (continue for 2 weeks then switch to long term antithrombotic treatment)
When should thrombolysis be considered?
Haemorrhagic stroke excluded
Onset of symptoms less than 4.5 hours ago (best results within 90 minutes)
What is the thrombolysis agent of choice?
Alteplase
Or recombinant tissue plasminogen activator (rt-PA)
What should be done 24 hours post lysis?
A CT to identify bleeds (non contrast)
What are the contraindications to thrombolysis?
Major infarct or haemorrhage on CT Mild/ non disabling deficit Recent surgery or trauma Previous CNS bleed AVM/ aneurysm Severe liver disease, varices, portal hypertension Low platelets Anticoagulants or INR>1.7
What does FAST stand for?
Facial asymmetry
Arm weakness
Speech difficulty
Time to call 999
How does fresh blood in the brain appear on CT scan?
Bright white
What investigations should be done to prevent further strokes?
BP - for hypertension, also look for retinopathy, nephropathy or cardiomegaly on CXR
Cardiac source of emboli - ECG, ECHO
Carotid artery stenosis - do carotid Doppler USS +/- angiography
BM
Lipids
Check for vasculitis and prothrombotic states, thrombocytopenia, hyperviscosity
Lacunar strokes are small infarcts around what areas of the brain?
Basal ganglia, internal capsule, thalamus, pons
Lacunar strokes have a strong association with what?
Hypertension
Approximately how many strokes are there per year in the UK?
150,000
What is the ROSIER score?
A diagnostic tool (in some cases the presenting symptoms may be vague) Firstly exclude hypoglycaemia then.. Loss of consciousness or syncope -1 Seizure activity -1 New acute onset of: Asymmetrical face weakness +1 Asymmetrical arm weakness +1 Asymmetrical leg weakness +1 Speech disturbance +1 Visual field defect +1
A stroke is likely if >0
What is the most commonly used classification system for ischaemic strokes?
Bamford classification (or oxford)
What criteria does the Bamford classification use to classify strokes?
Initial presenting symptoms and clinical signs. The system does not require imaging to classify the stroke (purely clinical diagnosis)
A total anterior circulation stroke affects ares of the brain supplied by…
The middle and anterior cerebral arteries
What 3 criteria need to be present to diagnose a total anterior circulation stroke? (TACS)
- unilateral weakness and or sensory deficit of the face, arm and leg
- homonymous hemianopia
- higher cerebral dysfunction e.g dysphasia, visuospatial disorder
All three need to be present
Describe a partial anterior circulation stroke (PACS)
A less severe form of TACS, in which only part of the anterior circulation has been compromised.
To diagnose a PACS what needs to be present?
Two of the following:
- unilateral weakness and / or sensory deficit of the face, arm and leg
- homonymous hemianopia
- higher cerebral dysfunction e.g dysphasia, visuospatial disorder
What need ps to be present to diagnose a posterior circulation syndrome? (POCS)
One of the following:
- isolated homonymous hemianopia (posterior cerebral artery)
- cerebellar dysfunction DANISH
- bilateral motor/ sensory deficit
- cranial nerve palsy and a contralateral motor/ sensory deficit
Describe a lacunar syndrome (LACS)
A subcortical stroke that occurs secondary to small vessel disease. There is no loss of higher cerebral functions e.g dysphasia
What needs to be present to diagnose lacunar syndrome?
Pure sensory stroke Pure motor stroke Sensory - motor stroke Ataxic hemiparesis Dysarthria- clumsy hand syndrome
When can a thrombectomy be done?
When the blood clot is in a large artery in the brain. Has to be carried out within hours of stroke starting.
Usually involves inserting cannula into an artery in groin and moving it up to the brain.
What is the ABCD2 score?
A risk stratification tool to identify patients at a high risk of stroke following TIA. Scoring > or equal to 4 = higher risk of stroke in 2 day period post TIA.
Age more than or equal to 60 = 1 point BP > or equal to 140/80 = 1 point Clinical features e.g unilateral weakness = 2 points Duration of symptoms > 60 mins = 2 10 to 59 = 1 point Diabetes = 1
In the case of a haemorrhagic stroke where anticoagulants and antiplatelets have been given, how do you reverse the effects?
Vitamin K
FFP
Platelet transfusions
What are the causes of haemorrhagic stroke?
Nearly always uncontrolled chronic hypertension Cocaine Aneurysm Clotting disorders Tumours
What is the likely cause of LOC in haemorrhagic stroke?
Large bleeds causing increased ICP - leading to herniation of brainstem and
/ or further infarcts in midbrain and pons
What is Weber’s syndrome ?
The result of an infarct on one side of the midbrain. It presents with:
- ipsilateral CN III paralysis
- contralateral hemiplegia
What is the National Institute of Health Stroke Scale used for? NIHSS
To quantity the impairment caused by a stroke. Max score is 42, minimum is 0.
0 = no stroke symptoms 1-4 minor stroke 5-15 moderate 16-20 mod to severe 21-42 severe
After having a stroke or TIA how long can you not drive for?
A month. After this you may do so as long as there is no permanent neurological sequale.
Pontine haemorrhage often occurs as a complication secondary to…
Chronic hypertension
Patients often present with reduced GCS, quadriplegia, miosis, absent horizontal eye movement
What is the standard thrombectomy time in acute ischaemic stroke?
6 hours of symptom onset
NICE recommends a pre stroke functional status of less than 3 on modified Rankin scale and more than 5 on NIHSS
Should IV thrombolysis be offered with thrombectomy?
Yes if within 4.5 hours
- to people who have acute ischaemic stroke and confirmed occlusion of proximal anterior circulation demonstrated by computed tomographic angiography or MRA
CONSIDER for proximal posterior circulation
Can ischaemic strokes occur if blood supply to the brain is reduced?
Systemic hypotension can cause blood supply to entire brain to be reduced resulting in a stroke e.g due to a cardiac arrest
Describe venous sinus thrombosis
Blood clots form in the veins that drain the brain, resulting in venous congestion and tissue hypoxia
How can haemorrhagic strokes be subclassified?
Intracerebral - bleeding within the brains secondary to ruptured blood vessel. Can be intraparenchymal (within brain tissue) and/ or intraventricular
Subarachnoid - bleeding outside brain tissue, between pia and arachnoid mater
How should fluids be managed?
Assess fluid status on admission and regular review
Greater than 80% who cannot swallow post stroke will recover within 2-4 weeks
Hypovolaemia can worsen the ischaemic penumbra and increase risk of complications - infection, DVT, constipation, delirium
Oral hydration if can safely swallow, IV if not
Describe how and why glycaemic control is important post stroke
Closely monitor and control blood sugar especially if NBM
Post stroke patients with hyperglycaemia have increased mortality independent of their age and stroke severity
Maintain BM between 4-11
Provide intensive management for diabetic patients post stroke
Hypoglycaemia can cause neuronal injury as well as mimic stroke related deficits
How should BP be managed?
Use of anti-hypertensives should only be used for BP control post stroke if hypertensive emergency with one or more of following:
Hypertensive encephalopathy
Hypertensive nephropathy
Hypertensive cardiac failure/MI
Aortic dissection
Pre-eclampsia
Lowering BP can potentially compromise collateral flow to affected region
If treatment indicated: cautious lowering by approx 15% in first 24 hours of stroke onset
Use IV labetalol, nicardipine, clevidipine as first line agents (rapid and safe titration)
If patient candidate for thrombolysis - BP reduced to 185/110 or lower
How should those with AF be managed post stroke/TIA?
Warfarin or direct thrombin or factor Xa inhibitor should be given as the anticoagulant of choice
Antiplatelets should only be given if needed for the treatment of other comorbidities
In acute stroke patients, in absence of haemorrhage, anticoagulant therapy should be commenced after 2 weeks, but if imaging shows a large infarct commencement should be delayed
Direct factor Xa inhibitor = Apixaban, rivaroxaban
What score is used to decide if anticoagulant therapy is required?
CHA2DS2VaSc
Congestive HF (1) HTN or treated HTN (1) A2 age >= 75 (2) 65-74 (1) DM (1) S2 prior stroke or TIA (2) Vascular disease - IHD, PVD (1) Sc sex (female) (1)
Score 0 = no treatment
Score 1 - males consider anticoagulant, females no treatment
Score 2 or more offer anticoagulant
If score suggests no need for anticoagulant, ensure a transthoracic ECHO has been done to exclude valvular HD - in combination with AF = indication for anticoagulant
When decided if a patient needs to be anticoagulated, the…score should be calculated to assess their risk of bleeding
HASBLED score (1 point for each)
HTN - uncontrolled, systolic >160
Abnormal renal function - dialysis or creatinine >200 OR abnormal liver function
Stroke history
Bleeding history
Labile INRs
Elderly >65
Drugs predisposing to bleeding - NSAIDS, antiplatelets or alcohol use
There are no formal rules on how to act on HASBLED score, although a score =>3 is high risk of bleeding
Underpinning the evolution of stroke symptoms = dysfunction of the neurovascular unit. Describe this process
The neurovascular unit = the functional unit of the CNS and relates to the relationships of neurones, glial cells and endothelial lumens. Hypoperfusion in the endothelial lumen will result in depletion if available ATP and consequently an impairment of energy dependent cell processes.
Impairment of membrane transport is responsible for the evolution of stroke symptoms. Membrane transport is essential for AP generation - drive all neuronal transmission.
Stroke syndrome evolves suddenly - AP cessation (binary on/off and no in between)
Focal - only neurovascular units in concerned territory affected
Fit into a vascular territory
Does migration of symptoms and sequential evolution of symptoms sit well with the AP phase transition (from on to off)?
No - consider stroke mimics
What is stereotyping?
Episodic recurrence of neurological disturbance in an identical fashion with complete resolution in between
When there is evidence of stereotyping, especially over weeks, months, years this becomes a strong indicator of stroke mimics - migraine with aura, focal siezures, functional neurological episodes
What is a cryptogenic stroke?
When the cause of the stroke remains unclear after thorough assessment
Cardiac emboli as the source can be strongly suspected in…
Those with AF Evidence of cardiomegaly Valvular heart disease HF Suspected endocarditis Following acute MI
When may you suspect thrombophilia as a cause?
Pregnant stroke patient
History of VTE
Multiple miscarriages
Active cancer
What should be part of routine post stroke surveillance?
Routine EWS review Mood Bowel and urine function Progress of stroke impairments Sleep Legs and calves for DVT Monitor bloods
What are the most common post stroke complications?
Recurrent stroke and extension - due to unaddressed aetiology, extension is due to loss of ischaemic penumbra
Raised ICP - haematoma expansion, malignant oedema, haemorrhagic transformation, hydrocephalus
Infections - chest infection common due to aspiration and UTIs due to incomplete bladder emptying - constipation/ bed bound
Immobility - VTE, constipation, bed sores
Mood and cognitive dysfunction - mood disorders common and can affect motivation and rehab compliance
Post stroke pain and fatigue - spasticity, joint dislocation, central/neuropathic pain
Spasticity, contractures and secondary epilepsy
When managing stroke, how can the interventions be classified?
Admission to stroke unit Revascularisation therapy Optimising physiology - via surveillance, prevention and early intervention of complications and nutritional support Secondary prevention Rehabilitation
Recovery trajectories and their corresponding functional plateaus can be divided into 3 groups (varying degrees in between ). What are they?
Early, high functioning plateau - extreme version = a TIA or a minor stroke, signifying excellent functional prognosis
Early, low functioning plateau - extreme version = TACS with no meaningful improvement in function as time passes, signifying poor functional prognosis
Delayed and medium functioning plateau - likely will define recovery in most moderate strokes. These patients will benefit from a change at sustained rehabilitation efforts until functional plateau achieved
What is the modified rankin scale?
A measure of global disability used to assess baseline function and evaluate outcomes and treatment impact after interventions
Runs from 0-6
0= no symptoms
1 = no significant disability, some symptoms but can carry out all usual activities
2= slight disability, can look after own affairs without assistance, but unable to carry out all previous activities
3 = moderate disability, requires some help but can walk unassisted
4 = moderate severe disability, unable to attend own bodily needs without assistance, unable to walk without assistance
5= severe disability, constant nursing care, bedridden and incontinent
6 = dead
