Neurology JC025: Sudden Hemiplegia And Dysphagia: Strokes, Neuroimaging 2 Flashcards
Stroke
- Most common adult neurological diseases
- 4th leading cause of death in HK
- Major cause of disability
Stroke:
- **Rapid onset of clinical symptoms
- Signs of **focal / global disturbances of cerebral functions
- Due to ***non-traumatic vascular causes
- Symptoms >24 hours or death
Transient Ischaemic Attack (TIA):
- Ischaemic stroke but symptoms resolve ***completely <24 hours
DO NOT use Cerebrovascular accident (CVA)!
New / Proposed definitions of Stroke
Stroke (ischaemic):
- Continuing symptoms >24 hours / fatal
or
- Imaging evidence of ***acute infarction
TIA:
- Focal neurological symptoms ***<1 hour
- Without evidence of acute infarction
Revision: Blood supply of brain
- Internal carotid artery (Anterior)
—> Middle cerebral artery (commonly infarcted) —> Penetrating artery
—> Anterior cerebral artery - Vertebral artery (Posterior)
—> Basilar artery —> Posterior cerebral artery
ALL join to form Circle of Willis at brain base
Types of Stroke
- Ischaemic stroke (ISS)
- 75-80%
- **Cortical / **Subcortical / **Lacunar (deep cerebral white matter, basal ganglia, or pons)
- Anterior / Posterior circulation
- Causes:
—> **Thrombosis
—> ***Embolism
—> Hypoxia - Intracerebral haemorrhage (ICH)
- 20%
- Supratentorial / Infratentorial
- Causes: ***Hypertensive - Subarachnoid haemorrhage (SAH)
- <5%
- Causes: ***Ruptured aneurysm
Mortality:
- SAH > ICH > Cortical infarct > Lacunar infarct
Disability:
- SAH > Cortical infarct > ICH > Lacunar infarct
***Pathogenesis of ISS, ICH, SAH
ISS:
- Atherosclerosis (Large vessel disease)
- **Thromboembolism
- **Cardioembolism
—> Non-valvular AF
—> Rheumatic heart disease
—> IE
—> Mechanical valve
—> Mural thrombus after MI
—> LV aneurysm with intraluminal clot formation
—> CHF
- **Small vessel disease
- Uncommon (Dissection, **Inflammation (Vasculitis (SpC Medicine)), Infection, ***Hypotension, Vasospasm, Hypercoagulability)
ICH:
- **Hypertension (esp. Undiagnosed / Uncontrolled)
- **Aneurysm
- **Vascular malformation
- **Bleeding tendency (more common ∵ widespread use of anticoagulant, antiplatelet)
- ***Cerebral amyloid angiopathy (elderly: deposition of amyloid material in cerebral artery —> fragile + inelastic)
SAH:
- ***Aneurysm (85%)
- Vascular malformation (10%)
Risk factors
Unmodifiable:
- Old age
- Male
- History of TIA / stroke
- ***Peripheral vascular disease
Modifiable:
- **Hypertension
- Heart disease
- **AF
- DM
- Hyperlipidaemia
- Smoking
- Alcohol abuse
- **Carotid artery stenosis
- **Use of oral contraceptives
- High plasma fibrinogen
- High blood viscosity
- Obesity
- Lack of exercise
- Homocystinemia
Common sites of Cerebral aneurysm
Usually at ***Bifurcation points
Visualised using
- ***Digital subtraction angiography (DSA)
- CT angiography
- MR angiography
***Clinical features of Stroke
S/S:
- indicate Location + Extent of damage
- Negative features from loss of functions
- Sudden / Rapid in onset
Carotid territory (ACA, MCA, Ophthalmic artery —> Anterior + Lateral cerebral hemispheres, Retina):
- **Contralateral Hemiparesis +/- Hemifacial weakness (non-specific for localisation)
- **Contralateral Hemisensory loss
- **Aphasia (if **dominant hemisphere involved)
- **Visuospatial disorientation (if **non-dominant hemisphere involved)
- **Visual disturbance (retinal stroke / **Amaurosis fugax: ipsilateral monocular blindness, **Contralateral homonymous hemianopia (Temporal / Parietal optic pathway))
- **Deviation of head and eyes towards lesion side (Prevost sign: ∵ damage of frontal eye fields) (Pontine lesion: Gaze deviation to contralateral side)
- Dysarthria
- Dysphagia
Vertebrobasilar territory (Cerebellum, Medulla, Pons, Midbrain, Occipital cortex):
- **Cortical blindness
- **Homonymous visual field defects
- **Diplopia
- **Nystagmus
- **Vertigo
- **Horner’s syndrome
- Dysarthria
- **Dysphagia
- **Crossed hemiparesis (Ipsilateral facial weakness + Contralateral limb weakness)
- Tetraparesis
- **Crossed unilateral sensory loss
- Bilateral sensory loss
- **Ataxia
Common warning symptoms:
- Sudden weakness / numbness of face, arm, leg on one side of body
- **Sudden dimness of loss of vision (particular in 1 eye)
- Loss of speech / trouble talking / understanding speech
- Sudden, severe headaches with no apparent cause
- **Unexpected dizziness, unsteadiness, sudden falls (esp. along with any of previous symptoms)
***DDx of Stroke
- ***Intracranial tumour
- ***Chronic subdural haematoma
- ***Encephalitis
- ***Multiple sclerosis
- ***Seizure
- Hysteria
Complications of Stroke
Cerebral:
- **Cerebral edema
- **↑ ICP
- Herniation
- **Haemorrhagic transformation (cellular swelling —> breakdown of BBB) (preserved collateral perfusion (from adjacent vessels / territories) or from reperfusion of infarcted tissues which have weakened vessels (i.e. from extravasation / diapedesis))
- **Epileptic seizures
Systemic:
- Bronchopneumonia
- **Aspiration pneumonia
- **DVT
- PE
- **Pressure sores
- **UTI
- ***Contractures
- Frozen shoulder
- CVS disturbances
- Fluid, Electrolyte disturbance
- Anxiety, Depression
Investigations of Stroke
Aim:
- Confirm diagnosis of Stroke
- Classify types
- Define underlying etiology + risk factors
- Reveal any complications
- ***CT / MRI of head —> define Ischaemic / Haemorrhagic
- Routine blood
- CBC
- LRFT
- ESR
- **Fasting glucose
- **Fasting lipoprotein pattern - ***ECG
- CXR
Further investigations:
5. Tests for **Prothrombotic states
6. **Echocardiogram (transthoracic / transesophageal)
- evaluate heart valves, cardiac function, intracradiac clots
7. **Holter monitoring
- evaluate presence of Paroxysmal AF / other arrhythmia
8. **USG Doppler study (extracranial, transcranial)
- Stenosis / Occlusion of extracranial, intracranial arteries
9. Cerebral angiography
- ***Digital subtraction angiography
10. LP (not usually used)
- SAH
- CNS infection
General Management of Stroke
- Keep patient comfortable + avoid complications
- Regular ***neuro-observation
- Monitor arterial BP
- avoid rapid lowering of BP - Avoid electrolyte imbalance, hypovolaemia, fluid overload
- ***Speech therapist
- dysarthria
- dysphagia
- aphasia - ***Ryle’s (NG) tube feeding
- depressed conscious level
- dysphagia - ***Monitor blood glucose level, Maintain euglycaemia
- ***Prevent pulmonary complications
- careful feeding practice
- early mobilisation
- chest physiotherapy - ***Low dose SC heparin for prophylaxis of DVT + PE
- Treat any infection vigorously, ↓ core / brain temperature when fever
-
**Avoid bladder over-distension, UTI
- condom catheter in incontinent man
- **indwelling catheter in both sexes if necessary
- intermittent catheterisation to measure post-void residual volume - Avoid constipation, faecal impaction, soiling
- high fibre diet
- stool softener (but not laxative) - Prevent pressure sores
- repositioning of weak limbs
- frequent turning
- use of cushions, egg-crater mattress, air mattress - Avoid contractures
- Early physiotherapy / occupational therapy devices - ***Control seizures
- Anti-convulsant therapy (∵ post-stroke seizure complicates 11% stroke patients without previous history of seizure) - Watch out for depression
- Avoid Iatrogenic complications
- Use medication cautiously + review frequently - Initiate measures to prevent future strokes / CVS events
- Risk factor identification + control - ***Antiplatelets for non-cardioembolic ischaemic stroke
- Aspirin
- Clopidogrel
- Slow-release form of dipyridamole - ***Anticoagulants for cardioembolic ischaemic stroke
- Healthy life style
- Regular exercise
Specific management of Stroke
- Acute Thrombolytic therapy: Recombinant Tissue Plasminogen Activator (tPA)
- activate Plasminogen —> Plasmin —> degradation of Fibrinogen + Fibrin
- IV within 3 (4.5) hours of **onset of stroke (or **last seen well time (SC teaching clinic)) (UpToDate: if exact onset time unknown —> use last seen well time)
- higher haemorrhagic complications
- numerous CI
- IV Streptokinase: ***unacceptable risk of haemorrhagic complications - Mechanical thrombectomy
- within **6 hours of onset of stroke due to **large artery occlusion
- Merci Retriever - Anticoagulation in acute stage
- Clinical trials failed to show any beneficial effects
- AVOID if extensive / haemorrhagic infarct, active / unidentified bleeding, lack of monitoring, uncontrolled HT, IE
- Logical but unproven:
—> definite / probable cardiac emboli
—> prophylaxis of thrombus formation / propagation / embolisation distal to occluded / severely stenotic large cerebral artery
- **ONLY used in **Cerebral venous sinus thrombosis (rare type of stroke) - Antiplatelet in acute stage
- ***ONLY small benefit
- Chinese Acute Stroke Trial: Aspirin 160mg within 48 hours of suspected acute ischaemic stroke —> significant risk reduction in mortality + non-significant risk reduction in death / dependency upon discharge
- International Stroke Trial: Aspirin 300mg given in ischaemic stroke within 48 hours —> achieved non-significant benefit - Neurosurgery
- Neuroimaging
- **CT / MRI (mandatory): delineate blood vessels + assess brain perfusion
- USG: neonatal brain, intraoperative imaging, extracranial vascular imaging
- **Conventional angiography: invasive, reserved for selected cases, used for ***Endovascular interventional therapy
Neurosurgery
- Carotid endarterectomy
- beneficial in symptomatic severe stenosis but small benefit in asymptomatic - Extracranial to Intracranial bypass
- negative results
- may have a role in patients with Cerebral hypoperfusion - Moyamoya disease
- ***Synangiosis (re-routing of vessels to provide a new source of blood for ischemic area)
—> Myoencephalosynangiosis
—> Duro-arterio-encephalosynangiosis
—> Formal STA-MCA (superficial temporal artery to middle cerebral artery) bypass - Treatment of ↑ ICP
- guided by ICP monitoring - Supratentorial infarct
- ***Surgical decompression
- QOL not improved, consider in young patients with non-dominant infarct - Cerebellar infarct
- Direct brainstem compression may lead to acute deterioration
- Prompt drainage of hydrocephalus, Infarctectomy, Posterior fossa decompression -
**Cerebellar haemorrhages
- Surgical emergencies: Prompt **CSF drainage + ***Clot evacuation - Basal ganglia haemorrhages (often related to HT)
- ***Endoscopy, Stereotaxy, Chemical clot liquefaction - Brainstem haemorrhages
- very high mortality
- ***Conservative treatment - Lobar haemorrhage
- ***Evacuation + Examination for haematoma cavity under microscope (∵ diverse etiologies, recommended for most cases except Amyloid angiopathy)
- if vascular abnormality suspected: pre-op angiographic study for surgical planning - Intraventricular haemorrhage + Associated hydrocephalus
- **Ventricular drainage + Chemical **clot lysis using Streptokinase, Urokinase, tPA - SAH
- ∵ ruptured cerebral aneurysm (85%)
- high index of suspicion
- prompt referral + early treatment
- Early ***microsurgical clipping (for good surgical candidates)
- Conservative treatment (for poor grade patients)
- Angioplasty + Intra-arterial papaverine (in Vasospasm)
Aims of Neuroimaging
-
Detection of haemorrhage —> **Diagnosis / Exclusion of Haemorrhagic stroke
- CT (*Recents clots are hyperdense)
- MRI (for specific clinical problems) - Ischaemic stroke: Assess age of lesion for planning of ***Thrombolytic therapy
- Evaluation of lesions requiring surgery / interventional therapy (e.g. space-occupying haematoma, aneurysm, AV malformation)
- Triage of patients
- Monitor progress
