Armando Hasudungan
Biology and Medicine videos

Stroke

Overview

Overview Third most common cause of death worldwide and most common cause of neurological disability. It is subdivided into ischaemic stroke (caused by vascular occlusion or stenosis) and haemorrhagic stroke (caused by vascular rupture, resulting in intra-parenchymal and/or subarachnoid haemorrhage).

Defintion
Stroke: Acute onset of a focal neurologic deficit due to a cerebral infarction or hemorrhage.
Transient Ischaemic Attack (TIA): Transient episode of neurological dysfunction caused by focal brain or retinal ischaemia, without infarction. When there is evidence of brain infarction, the episode is considered to be a mild stroke (if symptoms are minor or disappear).
Amaurosis Fugax: Transient monocular blindness that often is described as a gray shade being pulled down over the eye caused by ischemia to the retinal artery.

Risk Factors

Non-Modiafiable Risk Factors

  • Age
  • Family history
  • Diabetes mellitus
  • Chronic kidney disease
  • Sleep apnea
  • Infective endocarditis

Modifiable risk factors

  • Hypertension
  • Atrial fibrillation
  • Smoking
  • Symptomatic carotid artery disease
  • Sickle cell disease
  • Physical inactivity
  • Regular consumption of sweetened beverages
  • Low daily consumption of fish, fruits, or vegetables

In Women

  • Oral contraceptives
  • Migraine with aura
  • Immediate postpartum period
  • Pre-eclampsia
Remember The highest- risk patients for stroke are those with previous ischemic events such as TIA

Classification

Types of stroke

  • Ischaemic
    • Large vessels disease
    • Embolism
    • Small vessels (lacunar)
    • Uncertain
    • Rare – dissection, venus infarction
  • Haemorrhage
    • Primary intracerebral haemorrhage
    • Subarachnoid haemorrhage
Side note Although traditionally included as a type of stroke, subarachnoid haemorrhage is quite distinct. It presents with acute onset of severe headache or sudden loss of consciousness, is diagnosed by CT scan and managed by the neurosurgeon.

Anatomical classification – Oxford territorial classification
Total anterior circulation infarct
Partial anterior circulation infarct
Posterior circulation infarct
Lacunar infarct

Pathophysiological classification – TOAST
Large-artery atherosclerosis (embolus/thrombosis)
Cardioembolism (high-risk/medium-risk)

  • Atrial fibrillation
  • Valvular heart disease
  • Valvular prosthesis
  • Post MI
  • Dilated cardiomyopathy
  • Patent foramen ovale 
Small-vessel occlusion (lacune)
Stroke of determined aetiology

  • Arterial dissection
  • Hypercoagulable state
  • Haematological disorders
Stroke of undertermined aetiology

 

Think cardioembolism can cause multiple infarcts, often in different vascular territories. Whereas large artery atherosclerosis is a single area of infarct.

Anatomy and Phsyiology

Cerebral anatomy and blood supply

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Watch Anatomy – Cerebral anatomy and blood supply (Circle of Willis)

Sensory Pathways

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Motor Pathways

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Watch Motor Pathway

Signs and Symptoms

Rememeber FAST – acute signs and symptoms of stroke
Face: unilateral drooping
Arms: these may feel weak and numb. Patient may not be able to lift them
Speech: slurring of speech
Time: time for emergency medical attention

Symptoms

  • Acute onset
  • Arm weakness
  • Leg weakness
  • Self-reported speech disturbance
  • Facial weakness
  • Arm paresthesia
  • Leg paresthesia
  • Headache
  • Nonorthostatic dizziness

Signs 

  • Arm paresis
  • Leg paresis
  • Dysphasia or dysarthria
  • Hemiparetic/ataxic gait
  • Facial paresis
  • Eye movement abnormality
  • Visual field defect

Clinical Presentation based on location of “stroke” using the Anatomical classification – Oxford territorial classification:

  • Anterior circulation infarct
  • Posterior circulation infarct
  • Lacunar infarct
Anterior circulation (carotid territory)
Amaurosis fugax/retinal infarction.
Hemiparesis
Hemisensory loss
Hemianopia (optic tract and radiation)
Dysphasia
Sensory inattention
Visual inattention

Posterior circulation (vertebrobasilar)
Ataxia
Cranial nerve involvement:

  • diplopia
  • facial sensory loss
  • dysphagia
  • dysarthria
Hemiparesis (may be bilateral)
Hemisensory loss (may be bilateral)
Hemianopia (occipital lobe)
Cortical blindness—basilar artery occlusion

Lacunar
Pure motor strokes (face, arm, and leg) in the posterior limb of internal capsule
Pure sensory stroke (thalamus)
Ataxic hemiparesis (weakness and ataxia affecting the same side) due to a pontine lesion
Clumsy hand/dysarthria due to a lesion in the pons or in its internal capsule.

Investigations

Imaging

  • CT brain non-contrast to rule out haemorrhagic stroke
    • CT show 50% of lesions only however is most available and is fast
  • CT angiogram from aorta to circle of willis (COW)
  • MRI Brain

Infarcts best detected by MRI (but not in first few hours) > CT

Remember Imaging should be performed within 24 hours to exclude haemorrhagic stroke and other causes, e.g. tumours.

General

  • FBC
  • ESR
  • Ca2+ (hypo- or hypercalcaemia may be a cause of focal deficit).
  • EUC
  • LFT
  • Glucose
  • Thyroid function test
  • Lipid Profile
  • Coagulation profile

Other blood investigations to consider

  • Thrombophilia screen
  • Protein C, S, and antithrombin III defects
  • Factor V Leiden mutation
  • Antiphospholipid antibody
  • Lactate
  • Cardiac enzymes

Other investigation

  • Urine analysis – diabetes, haematuria in BE or vasculitis, toxicology screen
  • ECG – AF, MI
  • Echocardiogram and TOE.

Differential Diagnosis

CONDITION CLINICAL MANIFESTATION
Brain tumor Severe unilateral headache with nausea and vomiting
Central nervous system infection (e.g., meningitis, encephalitis) Fever, headache, confusion, neck stiffness, nausea, vomiting, photophobia, change in mental status
Falls/trauma Headache, confusion, bruising
Hypoglycemia Confusion, weakness, diaphoresis
Migraines Severe headaches with or without photophobia, younger age
Multiple sclerosis Diplopia, limb weakness, paresthesia, urinary retention, optic neuritis
Seizure Confusion with or without loss of consciousness, urinary incontinence, tongue biting, tonic-clonic movements
Subarachnoid hemorrhage Severe headache with sudden onset and photophobia
Vertigo (central or peripheral) Generalized dizziness and diaphoresis with or without hearing loss
Remember TIA is more likely with sudden onset, unilateral paresis, speech disturbance, or transient monocular blindness.

Aetiology

  • Ischaemic stroke (80%)
  • Cerebral haemorrhage
  • Subarachnoid haemorrhage

 

Management

The development of an acute stroke or transient ischaemic attack is a medical emergency.

INDICATION FOR CT/MRI
Patient on anticoagulants or with abnormal coagulation
Plan to give thrombolysis or immediate anticoagulants
Deteriorating conscious level or rapidly progressing deficits
Suspected cerebellar haematoma, to exclude hydrocephalus

General management

  • CT – to rule out Haemorrhagic cause
  • Admission to stroke unit
Remember Urgent brain imaging is required. Computerised tomography (CT) can help to exclude a stroke mimic and to differentiate haemorrhagic to ichaemic stroke

Acute ischaemic stroke 

  • Thrombolysis – alteplase (within 4.5 hours. >4.5 hours is not recommended)
    • If thrombolysis is not possible then antithrombotic therapy should be commenced
  • Antiplatelet drugs
    • Contraindicated in haemorrhagic stroke (CT)
    • Within 48 hours reduces mortality and recurrent stroke
  • Surgery
    • Neurosurgical hemicraniectomy – if cerebral oedema (cerebral oedema has 80% mortality)
Pharmacology Alteplase is a recombinant tissue plasminogen activator



Long term interventions following a stroke or TIA are aimed at preventing a future episodes (secondary prevention)

  • Education and rehabilitation
  • Antiplatelet therapy – aspirin + dipyridamole
  • Anticoagulant – warfarin if has Atrial fibrillation
  • Treat hypertension
  • Treat dyslipidaemia with statin
  • Treat Diabetes mellitus
  • Treat Atrial fibrillation
  • Smoking cessation
  • Alcohol cessation
  • Weight loss
  • Increase physical activity
  • Hormone Replacement Therapy should be stopped
  • Carotid endarterectomy or stenting
Side note Eligible stable patients should undergo carotid endarterectomy as soon as possible after the stroke event (ideally within two weeks).

Acute Haemorrhagic Stroke

  • Brain imaging with CT
  • Neurosurgical and neurocritical care evaluation
  • ICU admission
  • Supportive care – airway protection, aspiration protection
  • DVT/PE prophylaxis
  • Anti-pyretic measures – Fever has been associated with worse outcome after intracranial haemorrhage, and hypothermia is neuroprotective in animal models.
Remember Some patients with an intracerebral haemorrhage will be on warfarin therapy. Warfarin therapy must be urgently reversed with a combination of prothrombin complex concentrate, fresh frozen plasma and vitamin K.

Complications and Prognosis

Complications

  • Depression
  • DVT
  • Seizure
  • Brain oedema → ↑Intracranial pressure
  • Aspiration pneumonia
  • Infection
  • Delirium

Prognosis Ischaemic Stroke

  • Mortality following ischaemic stroke is 8% to 12%.
  • Long-term significant disability, sufficient to impair or prevent return to work, is seen in another 15% to 30%
  • Advanced age, female sex, and medical comorbidities have also been associated with worse outcomes

Prognosis Haemorrhagic Stroke

  • Mortality is significantly higher than for ischaemic stroke, in the range of 35% to 40%
  • Haemorrhage volume is the strongest predictor of outcome.

References

AAFP – Diagnosis of Acute Stroke 2015
Best Practice
UpToDate