Stroke Overview and Advances

Stroke Overview

• Stroke is a sudden neurological event of vascular origin.
• Stroke may be acute ischemic stroke (infarction, embolus, thrombus), hemorrhagic stroke (intracerebral, subarachnoid), or transient ischemic attack (TIA).

Learning Objectives

• Define "stroke".
• Describe the Circle of Willis and extracranial cerebral circulation.
• Understand Transient Ischemic Attack (TIA).
• Know stroke causes and types in young and old individuals.
• Understand stroke prevention factors.
• Know acute stroke investigation and management principles.
• Understand the natural history of acute stroke.

Stroke Advances

• Stroke units - full workup within 3-4 hours, enabling early recognition and neuroimaging.
• Early treatment - thrombolysis (door to needle < 60 min) and clot retrieval.
• Stroke prevention - risk factor management.
• Neurorehabilitation - intensive care.

Stroke Mimics

• Conditions to watch out for include: hypoglycaemia, mass lesions, seizures, migraine, functional hemiparesis, toxic/metabolic encephalopathy.
• Be aware of disguised strokes (movement disorders, confusion, vomiting).

Frequency of Stroke by Type

• Acute ischemic stroke - 65%+ (infarction - thromboembolic).
• Hemorrhage - 12% (subarachnoid - 6.6%, intracerebral - 5.1%).
• Transient ischemic attack (TIA) - 21%.

Stroke Risk Factors

• Vessel Wall: Hypertension, smoking, atherosclerosis, hyperlipidemia, diabetes.
• Vessel Lumen: Embolism (heart disease, impaired cardiac function, CHD, AFib, LVH, valvular disease), thrombosis (hematocrit, fibrinogen).
• Other: Race, family history, oral contraceptives, obesity.

Young Stroke (<50)

• All risk factors above.
• Vessel wall disease (large vessel, fibromuscular dysplasia, dissection, migraine).
• Small vessel disease (vasculitis, drug-induced, sickle cell anemia, anti-phospholipid syndrome).
• Congenital heart disease and complications (valve prolapse, patent foramen ovale).

Cerebral Autoregulation

• Pressure-dependent cerebral blood flow.
• Ischemic thresholds - electrical failures, complete ion pump failures, K+ release, failure to clear extracellular fluid (ECF), and cell death.
• Vasodilation in metabolically active tissue (increased blood flow & swelling).

Blood Supply to Brain

• Artery names (anterior cerebral artery, middle cerebral artery, posterior cerebral artery, anterior choroidal artery, posterior communicating artery)
• Important for understanding ischemic stroke locations.

Collateral Blood Supply to Brain

• Good collateral = silent occlusion, reduced infarct extent.
• No collateral = massive infarction, increased infarct size.
• Clot lysis = propagation 2, necrotic brain tissue, hemorrhagic infarcts.

Multiphase CT Angiography

• Used to assess collateral blood flow to brain.
• Phases 1, 2, and 3 show the impact of the blockage.

Stroke Imaging

• CT scanning evaluates for haemorrhage.
• It may detect ischemic changes delayed (60+ minutes) and usually requires follow-up MR.

Alberta Stroke Programme Early CT Score

• Evaluation of MCA (middle cerebral artery) infarct with points assigned to cortical & subcortical involvement.

Early Ischemic Changes (EIC)

• CT (non-contrast) shows swelling, sulcal effacement, hypoattenuation, and loss of differentiation, loss of lentiform nucleus.
• EIC response to reperfusion 1/3-2/3 of patients.
• Risk of hemorrhage and evaluation of clinical outcomes.

Stroke Classification

• Atherothrombosis (primary).
• Small vessel disease.
• Cardioembolism.
• Other causes.

Middle Cerebral Artery Occlusion

• Acute MCA infarction, signs of mass effect.
• Old MCA infarct, 5 years later (shows lesion).

Large Artery - Atherothrombosis

• Emboli originate at carotid bifurcation.
• Presence of ulcers in blood vessels, causing stenosis.
• Examples: arterial dissections, fibromuscular dysplasia.

Arterial Dissections

• Condition with damaged vessel walls.
• May involve any artery in the body, including the carotid.

Cardioembolic

• Conditions causing emboli (murals thrombus, prosthetic valve, endocarditis, patent foramen ovale, valvular heart disease, atrial myxoma).

Non-Valvular Atrial Fibrillation (Risk of Stroke)

• Paroxysmal, persistent, and permanent AF have varying stroke risks.

National Clinical Guideline for Stroke (UK & Ireland)

• Provides clinical guidance on stroke management in the UK & Ireland.

Thrombolysis & Clot Retrieval

• Time is crucial for treatment.
• Optimal outcomes occur within the first few hours.
• Less successful outcomes occur later in the timeframe.

Endovascular Treatment of Stroke

• Techniques for treating ischemic strokes.

Small Vessel Disease

• Focused on perforating vessels: end arteries, no collateral, no pressure reduction systems.
• Supply critical areas: brain stem.
• Common problems: design faults (Charcot-Bouchard aneurysms), lacunar infarctions.

Intracerebral Haemorrhage

• Hypertension, amyloid deficits, coagulation deficits, aneurysm, AVM, cavernoma, drugs, trauma are causes.

• Prevention includes controlling hypertension, coagulation issues, and avoiding drugs impacting blood clotting mechanisms.

Subarachnoid Haemorrhage

• Symptoms include severe headaches and neck stiffness.
• Risk factors include cigarettes and hypertension.
• Caused by berry (saccular) aneurysms.

Spontaneous Subarachnoid Haemorrhage

• "Worst headache".
• Possible outcomes: death, coma/alert status, survive/rebleed in 4-8 days, death.

Diagnostic Process (Subarachnoid)

• Initial assessment includes neuro-exam, neck stiffness, and CT scan with blood testing for subarachnoid.
• Lumbar puncture (if no xanthochromia).
• Angiography for determining exact cause.

Case Studies (Examples)

• Patient presentations, CT results, and diagnoses.