NEURO 1: BRAIN INJURY & STROKE Flashcards
Name 4 mechanisms that cause acute brain injury
- Ischemia & hypoxia
- Excitotoxins
- Reperfusion injury
- Abnormal autoregulation of blood flow
Why is the brain so sensitive to decreased perfusion?
Has low glycogen stores and low capacity for anaerobic metabolism
How long does the brain need to be deprived of oxygen to cause irreversible damage?
5-10 minutes
What is the main excitatory amino acid neurotransmitter that can cause excitotoxic effects?
Glutamate
What are 2 reasons why there may be excess glutamate in the brain?
- Cell membrane damage causing excess glutamate release
- Lack of ATP being made causing impaired glutamate reuptake
How does excess glutamate cause cell damage?
It binds to cell receptors that allow calcium and water entry into the cell causing cell swelling
What are 4 ways reperfusion can cause further damage to brain tissue?
- Reactive oxygen species
- Invasion of immune cells causing inflammation
- Compromised blood-brain barrier
- Platelet aggregation
If blood flow to the brain shows an impaired ability vasodilate (e.g. thrombosis, vasospasm, neutrophil aggregation), what is the end result?
Ischemia
If blood flow to the brain shows an impaired ability to vasoconstrict (e.g. vascular injury), what is the end result?
Hyperperfusion and edema
Which part of the Glasgow coma scale is the best predictor of patient outcomes following brain injury?
Motor response
What is the term for an abnormal flexion response to pain?
Decorticate posturing
What is the term for an abnormal extension response to pain?
Decerebrate posturing
What is the term for an abnormal persistent rhythmic/jerky movement of the eyes?
Nystagmus
What is the term for eyes not moving in the same direction?
Dysconjugate movement
What is the term for paralysis of the eye muscles?
Ocular palsy
What is the proper term for “doll eyes?”
Abnormal oculovestibular reflex
What is the proper term for the blink response?
Corneal reflex
What are 3 kinds of primary traumatic brain injury based on location?
- Focal (coup)
- Polar (coup-contrecoup)
- Diffuse
What are 3 kinds of primary TBI based on severity of injury?
- Concussion (altered LOC but no damage)
- Contusion (tissue damage present)
- Intracranial hematoma (bleed)
What are 3 types of intracranial hematoma based on compartment?
- Epidural
- Subdural
- Subarachnoid
What may cause an epidural hematoma?
Rupture of meningeal artery
What is the typical presentation of an epidural hematoma?
- Decreased LOC
- “Lucid interval”
- Rapid deterioration
What may cause a subdural hematoma?
Damage to bridging veins
How are the symptoms of subdural hematoma different from epidural hematoma?
May have a slower onset (e.g. subacute type shows symptoms 2-10 days later)
Why may a subdural hematoma become chronic?
After healing, granulation tissue is more fragile
What may cause a subarachnoid hematoma?
Rupture of cerebral aneurysm or AVM
What causes symptoms of subarachnoid hematoma like meningeal irritation, hydrocephalus, and ischemia?
Blood spreads through CSF
What does the acronym BEFAST stand for?
Balance (loss of balance, headache, dizziness)
Eyes (blurred vision)
Face (drooping)
Arms (weakness, esp. one sided)
Speech (difficulty)
Time (call 911 immediately)
What is the most common type of stroke?
Ischemic
What are 2 risk factors for thrombotic stroke?
Atherosclerosis
Coagulative disorders
What are 2 risk factors for embolic stroke?
Cardiac dysfunction
Cardiac dysrhythmia
In stroke patients, what is the term for the region of cells in the brain surrounding an ischemic core that still receive partial blood flow and may still be viable?
Penumbra
What is the term for a procedure to remove plaque from an artery to restore bloodflow?
Endarterectomy
What is the term for a procedure to open up an artery using a ballon or stent?
Angioplasty
Why should a transient ischemic attack be considered serious even if symptoms completely resolve?
About 1/3 of strokes are preceded by a TIA
What are 2 kinds of hemorrhagic stroke?
- Intracerebral hemorrhage (bleeding into brain parenchyma)
- Subarachnoid hemorrhage (bleeding into subarachnoid space–between arachnoid and pia)
What are 2 cardiac related risk factors for hemorrhagic stroke?
- Hypertension
- Use of anticoagulants
What are 4 ways a hemorrhagic stroke damages the brain?
- Compression injury to surrounding tissue
- Cuts off blood supply causing ischemia
- Direct toxic effects from bleed on brain tissue and vasculature
- Inflammation
How do the symptoms of hemorrhagic stroke differ from ischemic stroke?
The present in the same way, so imaging is required to determine the cause
In what way is the pharmacological management of ischemic and hemorrhagic stroke different?
Ischemic stroke: trying to break up the clot by using thrombolytics and anticoagulants
Hemorrhagic stroke: trying to encourage clotting to stop the bleeding by using reverse anticoagulants
