JC25 (Medicine) - Stroke Flashcards
Define stroke
Rapid onset
Focal or global disturbances of cerebral functions
due to non-traumatic vascular causes
Symptoms lasting >24 hours or leading to death
Stroke vs TIA
Difference?
Stroke = permanent neurological dysfunction/ impairment + imaging evidence of ischemia/ infarct
TIA: Focal neurological symptoms <24 hour without evidence of permanent neurological impairment or acute infarct
3 major types of stroke, prevalence
1) Ischemic stroke (75-80%): cortical, subcortical, posterior circulation, lacunar
2) Intracerebral hemorrhage (20%): Supratentorial, Infratentorial
3) Subarachnoid hemorrhage (<5%)
Mortality rate (in one year) of 3 major types of stroke
Subarachnoid hemorrhage (50%) Intracerebral hemorrhage (50%) Ischemic stroke - cortical (35%) Lacunar infarct (rare)
Causes of ischemic stroke
Ischemia:
1) Thrombosis
- Large vessel: atherosclerosis, arterial dissection, arterial vasospasm, fibromuscular dysplasia, moya moya disease, hyper-coagulability
- Small vessel: lipohyalinosis, athersclerosis
2) Embolism - clot fragment from heart or proximal vessels causing infarct, cardioembolic or non- cardioembolic stroke
3) Hypoxia - Poor cerebral perfusion causing border zone/ watershed area infarcts, no vascular occlusion
- Hypotension, diffuse athersclerosis
Common sites of carotid artery occlusion (5)
1) Atheroma +/- clot at bifurcation of common carotid artery into external and internal c.a. (most common)
2) Dissecting aneurysm of ICA below base of skull
3) Atheroma +/- clot at bifurcation of ICA into Anterior and middle c.a.
4) At siphon within cavernous sinus
5) Root of Common c.a. from brachiocephalic trunk or aorta (rare)
Causes of hemorrhagic stroke
Intracerebral hemorrhage
- hypertension
- Cerebral amyloid angiopathy
- Trauma
- Bleeding tendency
- AVM
- Aneurysm
- Brain tumor bleeding
- Cerebral venous thrombosis
- Hemorrhagic transformation
- Moya Moya
Subarachnoid hemorrhage:
- Trauma
- Berry aneurysm rupture
- Peri- mesencephalic non- aneurysmal SAH
causes of subarachnoid hemorrhage
Most common cause is spontaneous rupture of Saccular/ Berry aneurysms
Other causes:
Cerebral Vascular malformation, dural AV fistula
Transmural cerebral arterial dissection
Traumatic brain injury
Coagulopathies and bleeding tnedencies
Early vs Late presentation of Moyamoya disease?
Early: Ischemic symptoms due to progressive occlusion of c.a.
Late: Hemorrhagic symptoms due to fragile collateral vessels
Risk factors of stroke
Unmodifiable:
Old age
Male sex
History of TIA or stroke
Peripheral vascular disaease
6 cardiac causes of cerebral emboli
Mitral stenosis - mural and valvular thrombi
Subacute bacterial IE - vegetation, septic emboli
Valve replacement - thrombi
MI - mural thrombi
Ventricular aneurysm with intraluminal clot
Congestive HF, A-fib ***
Distribution of congenital cerebral anurysms that cause SAH?
Anterior circulation = 85%
- Anterior cerebral, middle cerebral and internal carotid artery and branches
Posterior circulation = 15%
- PCA, Basilar, vertebral and PICA
Clinical ddx of stroke?
MINT
Metabolic: hypoglycemia, hyperglycemia, Wernickes encephalopathy, Hypertensive encephalopathy, Hypoxia and hypercarbia
- check ABG, Glucose, O2 saturation, LFT, BP
infection
- CNS abscess and meningoencephalitis
- Bells palsy (HSV)
- Vestibular neuronitis
Check CBC with WBC differential
Neurological:
- Seizure with Todd’s paresis
- Brain tumor
- Traumatic brain injury
- Migraine with aura
- MS
- Conversion disorder
Check EEG, MRI, LP
Toxins - check toxicology screen and blood alcohol levels
Chorea and hemiballismus: typical location of lesion?
Chorea and hemiballismus: subthalamic nucleus
Acute occlusion of ICA leads to which neurological symptoms
Frontal lobe, parietal lobe and eye:
Hemiparesis +/- hemifacial weakness
Hemisensory loss
Visuospatial disorientation
Language disturbance (Parietal and Frontal)
Visual disturbance (Retinal stroke or amaurosis fugax)
Dysarthria and dysphagia (rare, bilateral innervation can typically compensate)
Acute occlusion of vertebro-basilar arteries lead to which neurological symptoms
Occipital lobe: Cortical blindness, homonymous visual field defects
Brain stem: Diplopia, Horner’s syndrome, dysphagia, dysarthria
Cerebellum: nystagmus, ataxia, vertigo
Long tracts: crossed unilateral sensory loss/ bilateral loss, crossed hemiparesis/ tetraparesis
Cerebral complications of stroke
Cerebral edema
Increase ICP, hydrocephalus, herniation
Hemorrhagic transformation of cerebral infarct
Seizure (at onset or later)
Systemic complications of stroke
Lung: bronchopneumonia, aspiration pneumonia
Peripheral vascular: DVT, PE
MSS: pressure sores, contractures, frozen shoulders
Urinary: Atonic bladder, overflow incontinence, UTI, stones
GI: Cholestasis, incontinence, constipation
Psych: anxiety, depression
…etc
First line investigation of suspected stroke
- Clinical dx of stroke type by symptoms, find cause and risk factors
- Imaging: CT (not sensitive to initial ischemic changes)or MRI brain (DWI), Cerebral angiography, Carotid USG
- Blood tests: CBC, Inflammatory markers, Lipoprotein, glucose, ABG, LFT, toxicology, alcohol level, clotting profile
- Cardioembolic cause: ECG, ECHO
- Lumbar puncture: blood in CSF/ xanthochromia if CT negative
Investigations into cardiovascular causes of stroke?
Test for coagulation/ prothrombotic states - clotting profile
ECHO
Holter monitoring (continuous ECG)
US doppler for peripheral vascular diseases
Blood culture (IE)
Metrics for continuous monitoring of acute stroke patient
Neuro-observation: GCS, limb power, pupil reflex…etc
All vitals
Electrolyte, fluids, glucose
Treat any infection and fever
Management of dysphagia/ dysarthria in acute stroke patient
Speech therapy
Ryle’s tube feeding
Long term Prophylaxis of further CVA after acute stroke?
Low dose subcutaneous heparin - prevent DVT, PE
Avoid prolong immobilization - repositioning, turning
Risk factor control
Antiplatelet for non-cardioembolic stroke (aspirin, clopidogrel)
Anticoagulation for cardioembolic ischemic stroke (Non-valvular A-Fib can use direct anticoagulants. Valvular A-Fib use warfarin)
Urinary and gastro-intestinal dysfunction management after acute stroke
Condom catheter or indwelling catheter - avoid urinary over-distension and gentio-urinary infection
Intermittent catheterization to measure residual urine volume
High fiber diet and stool softeners (lactulose) - avoid fecal compaction, constipation, soiling (NO LAXATIVES)
Common neuroleptic complication of stroke?
Seizures
11% stroke patients have spontaneous seizure
Ischemic Stroke treatment
Ischemic stroke confirmed after non-contrast CT head confirms no intracranial hemorrhage:
- Recombinant Tissue Plasminogen Activator = within 3-4.5 hours , no antiplatelet or anticoagulant for 24 hours, injected by IV or catheter-directed/ Trans-arterial approach to clot site
- Mechanical endovascular thrombectomy (surgery) = within 6 hours for large artery occlusion, stent retrieval of large clots +/- Catheter directed/ transarterial thrombolysis with tPA
- Carotid endarterectomy, angioplasty and stenting
Indication and contraindication of Anticoagulation therapy for stroke?
Indication = Cerebral Venous Thrombosis, Cardioembolic stroke, DVT, PE
Contraindication = Extensive infarct, Hemorrhagic infarct, Active or unknown bleed, IE, Uncontrolled HTN
Indication of antiplatelet therapy in stroke?
Non-cardioembolic stroke
All ischemic stroke or TIA after imaging excludes intracranial haemorrhage
24 hours AFTER intravenous thrombolysis
Long term prevention for recurrent stroke or short term DAPT therapy for for high risk non-cardioembolic stroke/ TIA (only 21 days)
Indication for carotid endarterectomy?
SYMPTOMATIC severe carotid stenosis, used after treatment of ischemic stroke to prevent ischemic stroke recurrence
Indication for Syangiosis?
Young patients with Moyamoya disease with acute stroke
Create collateral from extradural vessels to supply parenchyma
Indications for surgical decompression after stroke
Supratentorial infarct
Cerebellar infarct with brainstem compression
Intracranial and cerebellar hemorrhage
Most common causes of lobar vs basal ganglia hemorrhage?
Cerebral amyloid angiopathy gives lobar hemorrhage
Hypertension gives basal ganglia hemorrhage
Hemorrhagic stroke treatment
Supportive: ABC, sedatives, (BP control non conclusive),
- anticoagulant reversal (FFP, K infusion, PCC)
- prophylactic anti-epileptics
- Labetolol and Nimodepine to decrease BP and cerebral vasospasm
- Manage high ICP, EVD placement
- Microsurgical clipping, endovascular coiling/ embolization
- Stereotactic radiosurgery: Embolotherapy for AVM, Aneurysms
Ix and Treatment of SAH
Ix: CT brain and CT angiogram, MRI for subacute or recent bleed, LP for xanthochromia if CT negative
Tx:
Manage increase ICP and cerebral edema
Early microsurgical clipping, endovascular coiling
Angioplasty
intra-cranial papaverine OR Nimodepine for cerebral vasospasm
Lower BP - Labetalol
Prophylatic antiepileptics
Analgesics for headache
Conservative Tx for poor condition
Indication for US for neuro-imaging of stroke?
Neonatal brain imaging, Carotid artery imaging
Intraoperative or extracranial vascular imaging with US and doppler US
Use of CT and MRI in neuroimaging of stroke?
Use MRI Diffuse Weighted Image** for acute, subacute and recent bleeding
Use CT to exclude hemorrhagic stroke (NOT sensitive to initial ischemic changes/ edema)
