Lecture: CVA intro Flashcards
Acute signs and symptoms
F- face drooping
A- arm weakness, can be leg too, usually unilateral
S-slurred speech and confusion, dizziness, bad gait
T- time counts- 911, faster the hospital comes, the better
Loss of blood flow to the brain leads to
↓ O2 and metabolites (glucose), resulting in neuronal dysfunction and cell death
Stores of O2 and glucose are used within minutes triggering the onset of neurologic deficits
Without the blood flow, there is also a toxic build-up of metabolic waste, resulting in additional damage
Secondary damage: Ischemic cascade
Occurs in…
How it leads to tissue death and when does it happen
• Occurs in the aftermath of the acute infarct
• Damaged or dying neurons release excessive amounts of glutamate
• Cells that normally take up this neuro-transmitter are compromised, causing…
-Disturbance of energy metabolism (inability to produce ATP)
- Facilitates entry of Ca2+ into cells
- Activates catabolic enzymes that further degrade the neural structures
An ischemic cascade leads to cell death in how many hours
The ischemic cascade leads to an area of apoptosis & tissue death beyond the infarction, usually within 3-4 hrs
Ischemic stroke 3 mechanisms of injury
- Local hypoxia
- Local hypoglycemia
- Build-up of toxic metabolic waste
Penumbra, what happens in it
collateral arteries anatomizing with branches of the occluded vascular tree for several hours
The ischemic CVA is rarely fatal. . . BUT
Cerebral edema is a potentially fatal sequela!
• ↓ vascular perfusion into the brain à osmolality ↑ during ischemia
-> Influx of fluid into the brain to restore normal osmotic pressure ->EDEMA!
• Begins minutes after occlusion & peaks in 3-4 days
• Can cause ↑↑ ICP resulting in severe 2 ̊ structural damage (i.e.Brainstem herniation)
• Most frequent cause of death, esp. seen in large infarcts involving the MCA & ICA
Thrombotic CVA:
Most common in ___ arteries
Most common in • Internal carotid artery - vertebral artery - Basilar artery - middle cerebral artery
Thrombotic CVA:
Manifests as.. evolves over…
Often occurs during..
Often manifests as a focal neurologic deficit that evolves over several hours or days (symptoms occur over days)
• Often occurs during sleep
Thrombotic CVA:
Caused by…
• Is highly associated with atherosclerotic vessel disease, DM and HTN
Thrombotic CVA:
Poorer prognosis compared to…
• Poorer prognosis compared to embolic CVAs
Most common origins of an emboli
A-fib- blood flow is stagnant in L atrium
MI- damaged myocardium
Fat, bullets, catheter tips, sponge pieces
Onset of Embolic CVA
Onset is sudden with focal deficits occurring within seconds to minutes
• More frequently associated with TIA
• Associated with seizures, precipitating headache, transient confusion
and/or loss of consciousness (LOC)
• Emboli tend to terminally lodge in smaller vessels, producing more
discrete, focal deficits
Systemic cause of Ischemic CVA
- Low systemic perfusion secondary to cardiac failure or significant blood loss
- Widespread hypo-perfusion & ischemia leads to anoxic brain injury
- Neurological deficits are global & bilateral in nature
Areas most prone to an anoxic brain injury from ischemia:
- Hippocampus: memory deficits
- Purkinje fibers of the cerebellum: ataxia
- Basal ganglia: increased muscle tone
