Terminology/Etiology
What is a transient ischemic attack?
A temporary, focal cerebral ischemic event that results in reversible neurological symptoms but is not associated with a visible acute infarct on neuroimaging
In an ischemic stroke:
Infarction => ______ necrosis => Cystic cavity formation
Infarction => Liquefactive necrosis => Cystic cavity formation
What would be a classic cerebellar stroke sign?
Ataxia, nystagmus, slurred speech
Above what age is someone more likely to have an ischemic stroke?
Age >= 65 years of age
Corticobulbar innervation of facial motoneurons to muscles of the lower face are ispi/contra/bi-lateral
contralateral
What's the difference between an embolic stroke and thrombotic stroke?
Embolic: Embolic strokes are caused by the dislodgment of a blood clot (embolus) or other material (such as debris from a cardiac source) from a distant location in the body
Thrombotic: caused by the formation of a blood clot (thrombus) within an artery supplying the brain. This clot typically develops at the site of atherosclerotic plaque buildup
Name a likely cause of a transient ischemic attack
Cardiogenic embolism (e.g., from afib)
atherosclerosis (e.g., carotid artery stenosis)
If an MCA stroke affects the ______ lobe, the frontal eye fields cause gaze deviation toward the affected side and away from the side of hemiplegia
Frontal
What races are at a higher risk?
African Americans, Native Americans, Alaska Natives, and Hispanics are at higher risk.
The _______________ tract carries information for pressure, vibration, fine touch, and proprioception.
dosal column-medial lemniscal tract
Name 2 ways that someone can get an embolic stroke
What is glutamate excitotoxicity?
When you have energy deprivation, glutamate is excessively released in response to ischemia.
Brain infarction:
Blood flow disruption=> energy depletion=> excitotoxicity=> calcium dysregulation=>reactive oxygen species
Embolic strokes are most commonly affected by what artery?
Middle cerebral artery
Name 3 different modifiable risk factors for ischemic stroke.
Which cranial nerve has some lower motor neurons that receive only contralateral corticobulbar innervation?
Facial nerve (CN VII)
What are differences between transient ischemic attack and ischemic stroke?
TIA: temporary, focal cerebral ischemia that results in neurologic deficits without acute infarction or permanent loss of function (previously defined as lasting < 24 hours)
Ischemic Stroke: cerebral infarction due to insufficient cerebral blood flow (hypoperfusion), which results in ischemia and neuronal injury
During a brain infarction, calcium levels rise significantly due to excessive influx through _____ receptors. This disrupts cellular function.
NMDA receptors
If the parietal lobe is affected by stroke, what are 2 clinical features seen?
Contralateral sensory loss
Disorientation
Dominant hemisphere: Damage to angular gyrus results in Gerstmann syndrome.
Agraphia
Finger agnosia
Left-right disorientation
Acalculia
Nondominant hemisphere: contralateral agnosia (hemispatial neglect)
The cutoff for tPA administration is 3-4.5 hrs and Norma wasn't a candidate for tPA therapy.
What is an example of a tPA drug that would have been given if she was eligible?
Alteplase or Tenecteplase
Lesions in the brain stem that affect the _________ tract result in contra-lateral alteration of pain and temperature in the arm and leg
Spinothalamic tract
What is hemineglect and what are consequences of hemineglect/hemispacial neglect from a stroke affecting the non-dominant hemisphere?
In hemineglect, the integration of both hemispheres is impaired, resulting in stimuli processing of only one hemisphere. However, the underlying mechanisms are not well understood
Motor neglect: No spontaneous movements on one side of the body (the patient might be able to move the extremity if asked to).
Sensory/perceptual neglect: Patients become unaware of objects on their contralesional side.
What is the pathophysiology for a brain infarction?
Brain infarction:
Blood flow disruption=> energy depletion=> excitotoxicity=> calcium dysregulation=>reactive oxygen species
The case mentioned that Norma Jones had "a hypodense region extending from the basal ganglia to parietal cortex on the right side."
What artery was affecting this and what are 2 symptoms that Norma had that are caused by this?
MCA or lenticulostriate
To initiate secondary prevention of recurrent ischemic stroke, you can start antiplatelet treatment with ____ or _____ within 24-48 hours after symptom onset.
Aspirin or clopidogrel
The 2nd order neurons of the spinothalamic tract synapse in the ventral posterolateral nucleus of the ________.
Thalamus