Prodigy- Neuro Flashcards
What comprises the limbic system? (2.5)
- 3 roles
Hippocampus, amygdala, and part of the cortex
-role: cognition, memory, emotions
What 2 things is the cerebellum responsible for?
- Propioception
2. Maintaining posture and gait
What supplies 70% of the brains blood supply?
What about the other 30%?
70% - internal carotids
30%- two vertebral arteries
Increased/decreased/no effect on secretion/absorption rate of CSF:
Iso Sevo Des Fentanyl Etomidate
Iso & Fent - increase absoprtion (i love you so much i’m just going to absorb you into me)
Des- increased secretion (devil secretes/”secrets”)
Etomidate- decreases secretion (acetazolamide also decreases CSF secretion)
Normal CSF production is about _____mls/day
500
Which inhaled agent increased the secretion of CSF?
Desflurane
All the volatile anesthetics increase CBF in a dose-depedent manner - what is this referred to as?
uncoupling
What inhaled agent increases CMRO2?
nitrous oxide
Desflurane at ____MAC or less does not increase ICP
= 0.8MAC
T/F midazolam has a decrease in cerebral blood flow and CMRO2
True
T/F- midazolam depresses ventilation
True - by suppressing hypoxic drive
What are the 2 best preictors of outcomes in patients with a hemorrhagic stroke?
- Volume of hemorrhage
2. pt’s level of concsiousness
What is intraparenchymal hemorrhage?
bleeding into the brain tissue itself
Elective surgery should be delayed for at least how long following a stroke?
9 months
Elderly patients on anticoagulants are antiplatelet drugs who fall down and go boom are most likely to have what type of brain bleed
subdural hematoma
arachnoid - blood - dura
What kind of EKG changes are commonly seen within 48 hours of subarachnoid hemorrhage?
ST depression &
T Wave inversion
T/F cerebral AVM’s carry a high risk of rupture during induction of anesthesia
False
Pt’s taking cholinesterase inhibitors may exhibit a (sensitivity/resistance) to nondepolarizing agents
resistance
- have to compete with more acetylcholine
What is torticollis and what is another name for it.
*It can happen suddenly after the administration of anesthetic drugs - how would you reverse this ?
spasmodic contraction of the neck muscles
>thought to be a dysfunction of the basal ganglia
AKA Cervical dystonia
*Reverse with diphenydramine 25-50mg IV
Simple vs Complex seizures
Simple = no loss of consciousness
Complex = loss of consciousness
When someone has a nerve stimulator for seizures, what nerve is it stimulating?
The LEFT vagal nerve
*the right vagal nerve root is not used because it innervates the heart
Stimulating the (right/left) vagus nerve can produce severe bradycardia
right
Seizure control with diazepam dosing
0.1mg/kg q 10 minutes until seizure control or max dose of 30mg
Seizures medications primarily work by blocking what?
sodium channels
Which anticonvulant may produce a false-positive on a urine ketone test?
Valproic acid
Which anticonvulsant exerts it’s effect by decreasing the release of glutamate?
gabapentin
Pt’s with chiari malformation can cause medullary and cord compression with (flexion/extension) of the neck
extension
-think, it’s a defect where the cerebellum is deplaced downward, so if you extend you head back, it will go down further and cuase this compression
The incidence of pheochromocytoma and renal cell carcinoma is higher in patients with what syndrome?
Von Hippel-Lindau
Which drug is given to decrease CSF production?
What can it’s chronic use lead to and why?
Acetazolamide
-acidemia; because it inhibits tubular secretion of hydrogen ions (more hydrogen ions = acidemia)
What type of anesthetic should be avoided in those with bennign intracranial HTN?
Epidural anesthesia
bc the large volume of drug injected into the epidural space could further increase the ICP
What is a condition in which one vertebral body has slipped forward just past the adjacent vertebral body?
Spondylolisthesis
An anterior surgical approach to the cervical spine used to treat cervical disk disease requires retraction that can potentially damage which nerve?
The recurrent laryngeal nerve
What kind of fracture must be ruled out prior to nasal intubation?
basilar skull fracture
The diaphragm is innervated by fibers orgininating which nerve roots?
C3, C4, C5
Injury at or above which vertebra can result in severe bradycardia and hypotension
T6
The greatest risk of sux-induced hyperkalemia occurs during what time frame after SCI?
first 6 months after injury
sux should be avoided for the rest of their life though
Cheyne-Stokes breathing can indicate damage where? (2)
To the basal ganglia or cerebral hemispheres
What 3 conditions are associated with cnetral neurogenic hyperventilation?
- Closed head injury
- Thrombosis
- Cerebral embolism
What is anisocoria?
unequal pupils
What would you do if you saw that one patients pupil was +3mm and the other was +4mm
If no reason of concern, it’s okay - 20% of the poulation have this as a norma variant
What 2 things can caused fixed, dilated pupils?
- oculomotor nerve compression (uncal herniation)
2. administering anticholinergic drugs
T/F - anticholinergics can produce fixed and dilated pupils
True
What 3 things can cause pinpoint pupils?
- opioids
- organophosphate poisioning
- pons lesions
Which posturing is flexion vs extension?
flexion = decorticate (flex your core) decerebrate = extension
What is decorticate posturing signify impairment in?
what about decerebrate?
decorticate = diencephalon impairment
decerebrate = severe brain dysfunction
T/F- spinal reflexes may still be intact to declare brain death
True
Evoked potential waveforms have two major parameters that are observed- what are they?
Amplitude- measurement of intensity
Latency- how long it takes for the single and response to travel along the neural pathway
T/F- EMG is a monitor of ischemia
-false, but it is sensitive to mechanical and thermal damage
T/F- EMG is particuaraly sensitive to msucle relaxants
True - they should be avoided
What 3 procedures are SSEPs useful for?
spinal surgery,
CEA,
aortic surgery
Signficant changes in SSEPs are usually noted as a decrease in amplitude by at least ___% or increase in latecy by at least ____%
amplitude 50%
latency 10%
T/F- volatile anesthetics and N20 have the greatest adverse effect on SSEPs
True
-they both produce a decrease in amplitude and prolongation of latency.
What 2 medications can interfere with SSEPs by increasing the amplitude of signals
Etomidate and Ketamine
Motor evoked potentials would most accurately reflect an interruption of (anterior/posterior) spinal cord perfusion
anterior
Who shouldn’t undergo MEPs via magnetic stimulation? (4)
- spinal or bladder stimulatiors
- metallic foreign bodies
- pacemakers
- previous crani
what kind of evoked potentials utilize a device placed i nthe auditory canal that emits a broadband, repeat clik sound?
Brainstemp auditory evoked potentials
What kind of evoked potentials are useful for monitoring basic brainstem function?
Brainstem auditory EPs
Which evoked potentials are used on awake patients?
Visual patterned or unpatterned?
patterned
What do visual evoked potentials assess the integrity of? (4)
- eye
- optic nerve
- optic chiasm
- visual cortex
An awake, alert individual will primarily exhibit what kind of waves on EEG?
alpha and beta
When volatile agents are administered, there is an initial (increase/decrease) in (amplitude/latency) followed by a (increase/decrease) in both amplitude and latency
initial increase in amplitude
>decrease in both
What 2 things would display high frequency, low voltage activity on the EEG monitor?
Surigical stimulation or light anesthesia
Volatile anesthetics affect which kind of EPs the most vs least
most = visual
least - brainstem
How does the BIS monitor work?
it measures EEG waveforms in real-time and computes an index that can be used to measure the patients LOC
BIS range
-which indicates flatline vs awake
0-100
0- no activity/flatline
100- awake
a BIS score of ____ represents mild to moderate sedation
80
What BIS score represents an appropriate level of anesthesia with a low probability of explicit recall and being unresponsive to verbal stimuli.
40-60
Which agent can produce a suitable anesthetic state and still exhibit a high BIS value
Ketamine
T/F- the BIS monitor is considered to be less accurate in pediatric patients
True
T/F: transcranial doppler ultra sound measures the VOLUME of blood moving through the arteries
False
- it only assesses the velocity
Cerebral oximetry works based off which law?
Beer law
-states depedence betwee nthe transmission of light through a substance and product of absoprtion coefficent of the substance, and the distance the light travels through the material
T/F- patients with mass lesions should be presumed and managed as if they ahve increased ICP until proven otherwise
True
If your neuro patient is on corticosteroids or antiseizure medications, should the be held or continued perioperatively?
continued
In a patient with intracranial aneurysm, HTN during ___________ could cause rupture of the aneurysm
laryngoscopy
*these pts need a slow and deliberate induction with use of lidocaine and short-acting opioids to blunt the hemodynamic response to laryngoscopy.
Why is it important to avoid apnea and hypoventilation during induction of a neuro patient?
to prevent an increase in PaCO2 which would increase CBF and increase ICP
How do volatile agents provide some protection agaisnt cerebral ischemia? (3)
- increase CBF
- decrease ischemia-induced relase of glutamate
- activating ATP-depedent potassium channels
Mannitol:
onset:
peak:
onset 30 minutes
peak - within 2 hours
the neuroprotective ffects of hyperventilation typically diminishes after how many hours?
6
What would a high anion-gap metabolic acidos in a pediatric patient receiving a propofol infusion suggest?
Propofol infusion syndrome
What does hyperthermia do to the brain?
CMRO2 and CBV
what % of people with transsphenoidal hypophysectomy will develop DI?
40%
If having surgery for seizures and ECG is planned for use, what induction agent should be avoided adn which are okay?
avoid benzos
prop, opioids, and muscle relaxants are fine
1/2 hour before EEG, what should be done with your inhalational agent and propofol gtt
decrease to 1/2 MAC and stop propofol gtt if running
glucose consumption of brain is ____mg/100g/min
5mg/100g/min
An accumulation of blood between the arachnoid layer and the dura mater is known as A. a subdural hematoma B. an intraventricular hemorrhage C. a subarachnoid hemorrage D. an epidural hematoma
A. a subdural hematoma
All of the following are symptoms of acute spinal cord injury except:
A. Rigid paralysis below the level of the injury
B. Loss of temperature regulation below the level of the injury
C. Loss of spinal cord reflexes below the level of the injury
D. Loss of cutaneous sensation below the level of the injury
Not C….— I think A- with the key word being ACUTE. - flaccid paralysis is in the acute phase
Which of the following agents does not decrease cerebrospinal fluid production? A. Desflurane B. Furosemide C. Corticosteroids D. Acetazolamide
not C…
A- Des - increases CSF secretion
You are preparing to induce a patient who takes phenytoin for the treatment of seizures. You know that this patient would likely require a higher dose of A. cefazolin B. succinylcholine C. propofol D. vecuronium
D. vecuronium
A side effect of prolonged administration of mannitol is A. Decreased renal blood flow B. Hypokalemic hypochloremic alkalosis C. Hypo-osmolarity D. Arteriolar vasoconstriction
B. Hypokalemic hypochloremic alkalosis
You are preparing to induce a patient with uncorrected hydrocephalus for placement of a ventriculoperitoneal shunt. Which of the following agents would be least appropriate for this patient? A. Spironolactone B. Acetazolamide C. Desflurane D. Isoflurane
Not D —> C: Desflurane increases secretion of CSF and would worsen hydrocephalus
Inhalation anesthetics produce dose-dependent increases in intracranial pressure primarily because they
A. increase cerebrospinal fluid production
B. increase CO2 formation
C. increase the mean arterial pressure
D. increase cerebral blood flow
D. increase cerebral blood flow
At 1.5 MAC, which agent would maintain cerebral autoregulation more effectively? A. halothane B. desflurane C. sevoflurane D. isoflurane
C. sevoflurane
The level of sedation and BIS score are (directly/inversely) related
inversely
-higher score = less sedate
Which of the following alterations would you expect to see in a patient treated with acetylcholinesterase inhibitors for Alzheimer’s disease?
A. Greater tendency to exhibit baseline tachycardia
B. Shorter duration of action with succinylcholine
C. Decreased incidence of nausea
D. Resistance to nondepolarizing muscle relaxants
D. Resistance to nondepolarizing muscle relaxants
Spinal shock is a condition that can last A. 1-3 weeks B. 1-3 days C. 1-3 years D. 1-3 hours
A. 1-3 weeks
A patient with a history of spinal cord injury is undergoing a cesarean section. Which anesthetic modality would be the most effective at preventing autonomic hyperreflexia? A. Epidural anesthesia B. General anesthesia with an LMA C. General endotracheal anesthesia D. Spinal anesthesia
D. Spinal anesthesia
What is the approximate CSF volume (in mL)? A. 100 B. 200 C. 150 D. 50
C. 150
Which of the following characteristics is true of midazolam?
A. It increases cerebral blood flow
B. It decreases CMRO2
C. It prevents increases in ICP due to laryngoscopy
D. It stimulates the hypoxic ventilatory drive
B. It decreases CMRO2
What symptoms may be seen in a patient who is awake and experiences autonomic hyperreflexia?
Severe headache and blurred vision may occur due to severe hypertension and
nasal stuffiness may occur due to reflexive cutaneous vasodilation.
How is cerebral palsy classified?
according to the extremities involved (quadriplegia, monoplegia, etc.) and the type of neurologic dysfunction (hypotonic, spastic, athetotic, etc.).
What are the anesthetic considerations for the patient with cerebral palsy?
-major concern with intubation
-preferred extubation technique
-is MAC increased or decreased?
-emergence time increased or decreased?
They have an increased incidence of reflux and weak pharyngeal and laryngeal muscles.
Tracheal extubation may need to be delayed until the patient is fully awake and airway reflexes return.
MAC is generally decreased and emergence times are longer.
Is succinylcholine contraindicated in patients with cerebral palsy?
No
Even though they may suffer muscle weakness and spasticity, patients with cerebral palsy do not have an exaggerated hyperkalemic response to succinylcholine, nor are they more susceptible to malignant hyperthermia.
How do patients with cerebral palsy respond to nondepolarizing muscle relaxants?
prolonged recovery
but the opposite can be true if the patient takes antiseizure medications.
When lying in a horizontal position, the normal cerebrospinal fluid pressure is about ____mm of water or ______ mmHg.
130 mm H20
10 mmHg
What are some common causes of increased cerebrospinal fluid pressure?(4)
Brain tumor, hemorrhage, infection, hydrocephalus.
brain tumor = decreased reabsorption of the CSF = increased CSF pressure.
Hemorrhage or infection = blood cells or white cells in CSF obstruct the absorption channels in the arachnoid villi.
Hydrocephalus is an inborn cause of increased CSF pressure.
The neurons only contain about a _____minute supply of glycogen.
2
What percentage of cardiac output goes to the brain?
What % does it contribute to total weight
15% CO
2% weight
What are the four arteries that supply blood to the brain?
carotids and vertebrals
The left and right carotid arteries and left and right vertebral arteries.
70% and 30%
*What is the most effective method for protecting the brain during surgically-induced circulatory arrest?
Profound hypothermia between 14-18 degrees C for up to 20-30 minutes
*nagelhout
Normal rate of CBF in:
ml/100g/min &
ml/min
50-65ml/100g/min
750-900ml/min
What is the normal tissue PO2 in the brain? How do changes in tissue PO2 affect cerebral blood flow?
35-40mmHg
if < 30, body increases CBF to protect tissue from ischemia
<20mmHg = screwed
How do body tissues/organs survive 10-30 minutes without oxygen?
Why can’t the brain?
bc non neurona ltissues can obtain energy from anerobic mechanisms (extract glucose and glyogen for energy)
-the brain has a much higher metabolic rate (7.5x) of non-neuronal tissues and cant utilize these mechanisms very effectively.
T/F- interruption of blood flow to the brain for 5 s econds can produce unconsciousness
True
How does hydrogen ion concentration affect neuronal activity and cerebral blood flow?
An increase in hydrogen ion concentration depresses neuronal activity & causes an increase in blood flow to the brain.
By doing so, it will help ‘wash away’ the hydrogen ions, carbon-dioxide, and other acid precursors away from the brain which returns the hydrogen ion concentration back to normal.
*The brain receiveds 15% cardiac output or about ____ml/100g/min
50ml/100g/min
*nagelhout
*Which of the Rexed laminae are found in the dorsal horn of the spinal column? The ventral horn?
Dorsal = 1-6 Ventral = 7-9
Rate of CSF production
21ml/hr
did my other source say 30?
*What are two factors that may increase specific gravity of CSF?
hyperglycemia + uremia
*nagelhout
normal = 1.004- 1.009
6 drugs that can decrease CSF production
Acetazolamide (diamox) Furosemide corticosteroids spironalactone vasoconstrictors Etomidate
Medical management of hydrocephalus is done with which 2 agents
furosemide or acetazolamide to reduce CSF production
