Stroke Flashcards
Define subarachnoid haemorrhage
Bleeding into the subarachnoid space
- between the arachnoid mater and pia mater
Epidemiology of subarachnoid haemorrhage
6-8 cases per 100,000
Average onset 50-55
Higher incidence in men and black people
Risk factors for subarachnoid haemorrhage
Hypertension
Smoking
FHx
Autosomal dominant polycystic kidney disease
Pathophysiology of subarachnoid haemorrhage
Most commonly spontaneous rupture of berry aneurysms - commonly in the anterior circle of Willis
AV malformation
Arterial dissections
Use of anticoagulants
Presentation of subarachnoid haemorrhage
Sudden onset, thunderclap headache Photophobia Loss of consciousness CN III palsy - posterior communicating artery aneurysm compressing the ipsilateral CN III N+V Meningism
Ix for subarachnoid haemorrhage
CT head - hyperdense areas in basal cisterns, major fissures and sulci
FBC - leucocytosis
Clotting profile - may show coagulopathy - elevated INR, prolonged PTT
Troponin I - elevated in 1/4 of cases
LP - presence of RBCs or xanthochromia in 3 consecutive samples
Mx of subarachnoid haemorrhage
Cardiopulmonary support
- intubation, mechanical ventilation and sedation with benzodiazepines
- labetalol to keep systolic BP < 160
Surgical clipping/coil embolisation
Calcium channel blockers - vasospasm prophylaxis
Define extradural haemorrhage
Collection of blood between inner surface of skull and periosteal dura mater
Usually secondary to traum / skull fracture
Presentation of extradural haemorrhage
Loss of consciousness normally followed by transient recovery with ongoing headache
- caused by striping of dura from bone by expanding haemorrhage
Rapidly decreasing consciousness - haematoma enlarges increasing ICP
CN palsies - brain structures herniate
Ix for extradural haemorrhage
CT scan - bleeding limited by suture lines of skull
- hyperdense lemon shape
- midline shift away from bleed
- compression of ventricles
Mx of extradural haemorrhage
Prognosis good with early intervention
A-E assessment and neuro exam
Small - observe and manage conservatively
Large - urgent referral to neurosurgery for craniotomy and clot evacuation
Complications of extradural haemorrhage
Permanent brain damage Coma Seizures Weakness Pseudoaneurysm Arteriovenous fistula formation
Define subdural haematoma
Collection of blood between meningeal dura mater and arachnoid mater
Acute < 3 days
Subacute 3-21 days
Chronic > 21 days
Pathophysiology of subdural haematoma
Bleeding occurs due to shearing forces on corticla bridging veins with sudden change in velocity of head
Normally due to trauma
- may be spontaneous in anticoagulated patients
Presentation of subdural haematoma
Headache
Acute - severely depressed GCS, pupillary abnormalities
Chronic - insidious onset of confusion and cognitive decline
Ix for subdural haematoma
CT scan
- bleed does not cross midline due to falx cerebri
- banana shape
- midline shift away from bleed
- loss of cerebral architecture on affected side
- chronic bleed appears darker
Mx of subdural haematoma
Prognosis relatively poor - full recovery in 20% of patients
Small chronic - serial imaging to monitor progression
Acute - neurosurgical intervention to relieve raised ICP
Define stroke
Sudden onset of focal neurological deficit due to vascular cause
Types of strokes
Haemorrhagic - vascular rupture - intracerebral - subarachnoid - subdural Ischaemic - vascular occlusion or stenosis
Types of haemorrhagic strokes
Lobar
- cortex or subcortical white matter of cerebral hemispheres
Deep hemispheric
- supratentorial deep grey matter structures
- most commonly putamne and thalamic nuclei
Brain stem
- mainly pons
Cerebellar
- mostly dentate nucleus
Classification of ischaemic strokes
TOAST classification
Large artery atherosclerosis
- infarction in perfusion of extracranial or intracranial artery with > 50% stenosis
Cardioembolism
- infarction in presence of one cardiac condition
- AF
Small vessel occlusion
- infarction < 1.5cm in diameter in perfusion territory of small penetrating blood vessel
Stroke of other determined aetiology
- vasculitis, arterial dissection, hypercoagulable states
Stroke of indeterminate aetiology
Epidemiology of stroke
3rd leading cause of death and major disability
180 per 100,000
Ischaemic = 87%
Risk factors for stroke
Older age Fhx PMHx Hypertension Smoking DM AF Comorbid cardiac conditions - MI, decreased left VEF, valvular disease, cardiomyopathy Carotid artery stenosis Sickle cell disease Dyslipidaemia Obesity Alcohol abuse Oestrogen-containing therapy Illicit drug use Migraine Hypercoagulable state Haemophilia Anticoagulation
Pathophysiology of stroke
Ischaemic
- blood supply in cerebral vascular territory critically reduced
- thrombosis risk increased by Virchow’s triad
Haemorrhagic
- vascular rupture with bleeding into brain parenchyma
- expanding haematoma may shear neighbouring arteries -> futher bleeding
- mass effect -> increased ICP, reduced cerebral perfusion, ischaemic injury
Presentation of stroke
Visual loss or visual field deficit - commonly in patients with posterior circulation ischaemia - unilateral - carotid or vertebrobasilar ischaemia - bilateral - vertebrobasilar ischaemia Weakness - complete or partial loss of muscle strength in face/arms/kegs - all three suggests deep hemispheric involvement Aphasia - expressive or receptive Ataxia - cerebellar pathology Sudden onset Diplopia Sensory loss Dysarthria Gaze paresis Neck pain Miosis, ptosis facial anhidrosis Altered level of consciousness Photophobia and headache
Define stroke chameleons
Presentations which resemble other conditions but are actually stroke
Venous infarcts - impaired drainage and gradual onset
Small cortical strokes - peripheral nerve lesions
Limb shaking TIA
Occipital stroke - present with confusion and delirium - visual field defects
Ix for stroke
Non-enhanced CT - within 1 hour - ischaemic - CT normal in first few hours, hyperattenuation of relevant vessel due to clotted blood, loss of grey-white matter differentiation, hypodensity of cortical tissue - haemorrhagic - hyperdense lesion CT with contrast angiography - if thrombectomy indicated CT perfusion imaging or MRI alternative Serum glucose - exclude hypogylcaemia Serum electrolytes Urea + creatinine - renal failure may be contraindication to mx Cardiac enzymes - concomitant MI ECG - exclude arrhythmia or ischaemia FBC Clotting screen Carotid USS - carotid stenosis
Oxford classification of ischaemic strokes
Total Anterior Circulation Stroke - TACS
- usually cardiac emboli
- affects area of brain supplied by middle and anterior cerebral arteries
Partial Anterior Circulation Stroke - PACS
- usually large vessel disease
- less severe form or TACS
Posterior Circulation Syndrome - POCS
- involves damage to area of brain supplied by the posterior circulation - occipital lobe, cerebellum or brainstem
Lacunar Syndromes - LACS
- usually atheroma in situ
- subcortical stroke that occurs secondary to small vessel disease
- no loss of higher cerebral functions
Classification of Total Anterior Circulation Stroke
All 3 must be present
- unilateral weakness of face, arm and leg
- homonymous hemianopia
- higher cerebral dysfunction - dysphasia, visuospatial disorder
Classification of Partial Anterior Circulation Stroke
2 of the following present
- unilateral weakness of face, arm and leg
- homonymous hemianopia
- higher cerebral dysfunction - dysphasia, visuospatial disorder
Classification of Posterior Circulation Syndrome
One of the following
- cranial nerve palsy and contralateral motor/sensory deficit
- bilateral motor/sensory deficit
- conjugate eye movement disorder - horizontal gaze palsy
- cerebellar dysfunction - vertigo, nystagmus, ataxia
- isolated homonymous hemianopia
Classification of Lacunar Syndrome
One of the following present
- pure motor stroke - lenticulostriate artery
- pure sensory stroke - thalamoperforator artery
- sensorimotor stroke
- ataxic hemiparesis
Assess the severity of stroke
National Institutes of Health Stroke Scale Level of consciousness o Level of alertness (0-3) o Verbal (0-2) o Visual and motor (0-2) · Best gaze (0-2) · Visual fields (0-3) · Facial Palsy (0-3) · Arm motor (0-4) · Leg motor (0-4) · Limb ataxia (0-2) · Sensory (0-2) · Best language (0-3) · Dysarthria (0-2) · Extinction and inattention (neglect) (0-2) 0 – no stroke symptoms 1-4 – minor stroke 5-15 – moderate stroke 16-20 – moderate to severe stroke 21-42 – severe stroke
Define ROSIER
Used in A+E for stroke diagnosis
Stages of ROSIER
Exclude hyperglycaemia first
Loss of consciousness or syncope = -1
Seizure activity = -1
New, acute onset of asymmetrical face weakness = +1
New, acute onset of asymmetrical arm weakness = +1
New, acute onset of asymmetrical leg weakness = +1
New, acute onset of speech disturbance = +1
New, acute onset of visual field defect = +1
A stroke is likely if the score is > 0
Mx of ischemic stroke
Emergency - IV alteplase - thrombectomy Conservative - admission to stroke unit to optimise physiology and monitor Medical - aspirin 300mg daily for 2 weeks - clopidogrel 75mg TD after aspirin finished Surgical - carotid endarterectomy
How does alteplase work
Activates plasminogen to form plasmin
- degrades fibrin and breaks up thrombi
Indications for alteplase
Clinical diagnosis of ischaemic stroke
- NIHSS 4
- aphasia
- binocular visual field deficit
- swallowing deficit
- unable to walk or self-care independtly
Absolute contraindications for alteplase
BP > 185/110 after 2 attempts to reduce Surgery or trauma within last 14 days Active internal bleeding Haematology abnormalities - INR>1.7 or APTT > 40 Arterial puncture at non-compressible site or LP in last 7 days Symptoms of subarachnoid haemorrhage IE, pericarditis Childbirth in last 4 weeks Acute pancreatitis Severe liver disease
Conservative mx of stroke
Admission to stroke unit to optimise physiology - Maintain good glycaemic control - Ensure BP doesn't drop - Ensure good sleep - Monitor O2 sats - Nutritional support - Rehabilitation Lifestyle modifications - Smoking - Weight - Alcohol - Diet - Exercise
Mx of underlying stroke pathologies
Anticoagulation if has AF - balance bleeding and clot risk - CHADVASC - warfarin - HASBLED - DOACs Antihypertensives - target of 130/80 - ACE inhibitors - CCB - Thiazides Statins for hypercholesterolaemia Glycaemic control for diabetes
Mx of haemorrhagic stroke
Neurosurgical evaluation Airway protection Blood pressure control - labetalol - nicardipine
Complications of stroke
Dysphagia may lead to aspiration
Prolonged immobility
- DVT
- Pressure ulcers
- Constipation
- urinary retention
Seizures - abnormal glial activity
Recurrent strokes
Raised ICP
- malignant oedema
- hydrocephalus
- haemorrhagic transformation
Cognitive issues
Mood changes
Fatigue
Pain
Alteplase-related orolingual oedemaFeatures of TIA
Symptoms lasting less than 24 hours
Refer to TIA clinic within 24 hours
Screen for subsequent stroke post TIA
ABCD2 score
- A - age > 60
- B - blood pressure > 140/90
- C - clinical features - unilateral weakness = 2, dysphasia without weakness = 1
- D - duration - >60mins = 2, 10-60mins = 1
- D - diabetes
Mx of TIA
< 3 = specialist assessment within week
> 3 = specialist assessment in 24 hours
Start aspirin 300mg OD and simvastatin 40 mg OD
