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
Evolution of CT findings in Stroke
Hyperacute infarct (Normal up to 12 hours):
- **Hyperdense artery (∵ Thromboembolism)
- **Hypodense Lentiform nucleus (Putamen + Globus pallidus)
- Normal in 50-60%
12-24 hours:
- Progressive **loss of gray-white differentiation, insular ribbon
- **Sulcal effacement
1-3 days:
- Wedge-shaped **Hypodensity (∵ **Cytotoxic edema)
- Haemorrhagic transformation of infarct
4-7 days:
- **Maximal cytotoxic edema (may need craniectomy)
- **Gyral enhancement with contrast injection (persistent breakdown of BBB —> leakage of contrast into infarcted tissue)
1-8 weeks:
- **Subsiding edema
- **↓ Attenuation in hypodense area (back to normal appearance)
> 8 weeks:
- ***Encephalomalacia (Brain shrinkage: Infarcted tissues totally lost, replaced by fluid)
- Resolution of Gyral enhancement
Evolution of MRI findings in Stroke
Hyperacute infarct (Within 1 hour):
- **Abnormal (+ve) DWI (Diffusion-weighted imaging): visualise developing acute infarction
- **Abnormal perfusion pattern: Artery without flow void, reveal ischaemic area / established infarction
12-24 hours:
- T2W hyperintensity (edema)
- **Loss of gray-white differentiation / insular ribbon
- **Sulcal effacement
- Meningeal enhancement
1-3 days:
- Wedge-shaped ***T2W hyperintensity (∵ ↑ H2O)
- Cytotoxic edema
- Haemorrhagic transformation
4-7 days:
- Maximal cytotoxic edema
- Gyral enhancement
1-8 weeks:
- Subsiding edema
> 8 weeks:
- Encephalomalacia
- Resolution of Gyral enhancement
Interventional Neuroradiology
- Transarterial thrombolysis
- Embolotherapy for AVM and aneurysm
- Angioplasty (+/- Stenting) for arterial stenosis
SAH CT
- ***Subarachnoid blood
- ***Blood-CSF level in ventricles
- ***Ballooning of ventricles (Acute hydrocephalus)
Last seen well time vs Symptom onset time (web)
Last seen well time:
- Date and time at which the patient was last known to be ***without the signs and symptoms of the current stroke or at their prior baseline.
Symptom onset time:
- Date and time of discovery of **patient’s symptoms (i.e. when the patient was found with symptoms). This should be the **earliest time that patient was known to have symptoms.
If the event was witnessed, then the last known well date and time and the discovery date and time will be identical. Record both, even if identical.
Stroke Severity Score (SC Teaching Clinic)
***NIHSS (National Institutes of Health Stroke Scale):
- Quantify impairment caused by a stroke
- 11 items, each of which scores a specific ability between a 0 and 4
- Max score: 42
Score:
- 0: No stroke symptoms
- 1-4: Minor stroke symptoms
- 5-15: Moderate stroke
- 16-20: Moderate - Severe stroke
- 21-42: Severe stroke
