Stroke Overview and Risk Factors

Stroke Overview

• Stroke is a sudden neurological event of vascular origin.
• Stroke is classified into different types:
  • Acute Ischemic Stroke (65%+):
    • Infarction (thrombo-embolic)
  • Haemorrhage (12%):
    • Subarachnoid haemorrhage (6.6%)
    • Intracerebral haemorrhage (5.1%)
  • Transient Ischemic Attack (21%)

Learning Objectives

• Define "stroke."
• Describe the Circle of Willis and extracranial cerebral circulation.
• Understand Transient Ischaemic Attack (TIA).
• Know causes and types of stroke in different age groups.
• Understand stroke prevention, including risk factors.
• Understand principles of acute stroke investigation and management.
• Understand the natural history of acute stroke.

Stroke Risk Factors

• Vessel Wall:
  • Hypertension
  • Smoking
  • Atherosclerosis
  • Hyperlipidaemia
  • Diabetes
• Vessel Lumen:
  • Embolism (Heart disease, impaired cardiac function, CHD, AFib, LVH by ECG, valvular disease)
  • Thrombosis (Haematococrit, Fibrinogen)
  • Other (Race, family history, oral contraceptives, obesity)

Young Stroke (<50)

• All above factors apply
• Additional factors include:
  • Vessel Wall Disease:
    • Large vessel: fibromuscular dysplasia, dissection
    • Small vessel: migraine, vasculitis, drug-induced conditions, sickle cell anaemia, anti-phospholipid syndrome
  • Heart: Congenital heart disease and complications (valve prolapse, patent foramen ovale)

Cerebral Autoregulation

• Cerebral blood flow (CBF): Ischemia thresholds
• Vasodilation occurs.
• CBV in metabolically active tissue = isodense swelling.

Blood Supply to Brain

• Middle cerebral artery (MCA)
• Anterior cerebral artery
• Posterior cerebral artery
• Anterior choroidal artery
• Posterior communicating artery

Collateral Blood Supply

• Good collateral: silent occlusion, infarct extent reduced
• No collateral: massive infarction
• Collateral blocked: propagating thrombus (massive infarction)

Thrombolysis & Clot Retrieval

• Time is brain:
  • < 1.5 hours: 1:4 patients
  • 1.5 – 3.0 hours: 1:7 patients
  • 3.0 – 4.5 hours: 1:14 patients

Endovascular Treatment

• Techniques and procedures used to deal with strokes.
• Rapid endovascular treatment assessment of ischemic stroke.

Small Vessel Disease

• Perforating vessels: end arteries, no collateral, no pressure reduction
• Critical areas: present brain stem(s), design fault. Conditions like Charcot-Bouchard aneurysm
• Lacunar infarction: small infarct but devastating consequences by location

Intracerebral Haemorrhage

• Causes:
  • Hypertension
  • Amyloid
  • Coagulation deficits
  • Aneurysm (AVM)
  • Cavernoma
  • Tumour
  • Drugs (therapeutic & recreational)
  • Trauma
  • Unknown (family history)
• Special Considerations:
  • Cerebellum and Neurosurgeon
  • Venous sinuses
• Summary
  • Hypertension
  • Small vascular malformation (AVM)
  • Sympathomimetic drugs (cocaine/amphetamines)
  • Cerebral amyloid angiopathy (see lecture)
  • Anticoagulants + other bleeding disorders

Subarachnoid Haemorrhage

• Association: Polycystic kidneys
• Causes:
  • Berry (saccular) aneurysm (congenital defect, progressive enlargement)
  • Risk factors: cigarettes, hypertension
• Outcome:
  • Death
  • Coma or alert
  • Survival - rebleed (4-8 days)
  • Death
• Diagnosis:
  • Worst headache in life
  • Neck stiffness
  • Xanthochromia (yellowing of CSF)

This quiz provides a comprehensive overview of strokes, their classifications, and learning objectives related to their prevention and management. Participants will explore the anatomy involved, recognize risk factors for different demographics, and understand the essential aspects of stroke investigation and management.