Ischemic Stroke Patho Flashcards
What occurs when the arterial blood supply cannot meet the demands of the brain cells causing cell damage or death?
An ischemic stroke
Cells that are damaged are
Ischemic
Cells that are dead are
Infarcted
What is the penumbra?
The cells around the core infarct that are ischemic but not infarcted
Tissue in the penumbra is called
Apoptotic
Tissue in the infarcted area is called
Necrotic
What is the central mechanism of neuronal death?
Hypoxia or anoxia
What is the necrotic pathway?
Cell energy failure and rapid breakdown. Caused by lack of O2 and glucose and cellular electrolyte exchange from the loss of arterial perfusion
What is apoptotic pathway
Programmed cell death in penumbra
Why do the cells die in the penumbra?
Cells are “programmed” to die in an organized fashion caused by nearby cell death.
Necrotic cells swell and turn liquidy…this puts pressure on nearby cells which then die
The goal of therapy in the first few hours of an ischemic stroke is to
Restore blood flow to the penumbra
What factors influence the rate and extent of penumbral tissue and infarcted tissue is
The rate and onset of ischemia.
The degree of collateral circulation perfusing the infarcted zone.
Functionality of systemic circulation.
Hematologic factors.
Metabolic factors such as elevated temp, hyper/hypoglycemia.
Why does a low EF increase the risk for an embolic stroke?
An EF of 20-30% can cause stasis
What are the 2 mechanisms of carotid occlusive strokes
Hemodynamic reduction of flow.
Embolism into downstream cerebral circulation
What are the MRI characteristics of Hemodynamic strokes causes by carotid occlusion
Hemodynamic strokes will have a watershed distribution of infarction and reduced flow in the distal beds of MCA, ACA,and PCA
