CPAT 3202 – Neuro 1 Quiz

Stroke Overview

• Stroke is Australia's third leading cause of death and a major disability cause.
• Approximately 60,000 new and recurrent strokes occurred in Australia in 2011.
• Mortality rates: 1 in 5 first-ever stroke victims die within a month; 1 in 3 die within a year.
• Stroke prevalence: more fatalities in women than from breast cancer, and in men than from prostate cancer.
• Around 88% of stroke survivors experience some form of disability.
• Economic impact: approximately 6billionannuallyindirectcosts,plus6 billion annually in direct costs, plus 6billionannuallyindirectcosts,plus26 billion due to premature mortality and disability.

Ischaemia vs Hypoxia

• Ischaemia results from a decrease in blood supply, always pathogenic and leads to nutrient deficiency and waste buildup.
• Hypoxia, a decrease in oxygen supply or utilization, can be non-pathogenic if blood flow increases.

Types of Stroke

• Ischaemic strokes account for 88% and include:
  • Large artery athero-thrombosis (most prevalent)
  • Embolism
• Haemorrhagic strokes represent 12%.
• There are cases categorized as "unknown."

Consequences of Stroke

• Effects vary based on stroke type, affected vessel size, anatomical location, time elapsed since occurrence, and treatment (e.g., thrombolysis within 4 hours).

Risk Factors for Ischaemic Stroke

• Key risk factors include:
  • Age
  • Hypertension
  • Obesity and diabetes
  • Hyperlipidemia
  • Family history of stroke
  • Heart disease, especially atrial fibrillation
  • Cigarette smoking
  • Previous stroke
  • Ethnicity

Stroke Subtypes

• Ischaemic strokes subtypes:
  • Large artery athero-thrombosis
  • Small (penetrating) artery occlusion
  • Embolism
• Haemorrhagic strokes include parenchymal and lobar haemorrhages.

Pathogenesis of Athero-thrombus

• Initiated by hyperlipidaemia and endothelial damage leading to fatty streaks and atherosclerotic plaques, eventually causing vessel occlusion.

Ischaemic Penumbra

• Area surrounding a stroke's core where retaining blood flow can preserve neuron viability.

Acute Ischemia Molecular Events

• Glutamate release increases intracellular calcium, causing membrane and DNA damage.
• Decreased energy production due to failed ionic pumps and mitochondrial injury.

Morphological Changes in Brain Infarct

• Acute (≤ 2 days): Softening, swelling from edema, infiltration of neutrophils, and ischaemic neuronal changes.
• Subacute (days to weeks): Liquefaction leading to cavitation, presence of foamy macrophages, and reactive astrocytes forming glial scar.
• Remote (weeks onward): Presence of cavitation, glial scar, and haemosiderin-laden macrophages indicates past injury.

Lacunar Infarcts

• Caused by occlusion of small penetrating arteries, linked to hypertension, resulting in small infarcts in deep brain structures.
• Often asymptomatic or result in transient ischemic attacks (TIAs).

Sources of Emboli

• Thrombo-emboli can originate from:
  • Arteries (e.g., carotid, aortic arch)
  • Heart conditions like atrial fibrillation
• Other types include atheroma and systemic emboli from sources such as fat or air.

Major Causes of Haemorrhagic Stroke

• Hypertension is the primary risk factor leading to arteriolar sclerosis.
• Can result in parenchymal and lobar hemorrhages, with lobar hemorrhage often associated with cerebral amyloid angiopathy, prevalent in Alzheimer's disease patients.

Diagnosis and Management

• CT scans are essential for identifying hemorrhage; if present, thrombolysis should be avoided to prevent complications.