Neurology, Monitoring, & Associated Pharmacology Flashcards

1
Q

This device records electrical activity in the brain?

A

Electroencephalogram (EEG)

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2
Q

Irregular patterns on an EEG can help dx these neurological dysfunctions

A
  • Seizure disorders
  • Head injury
  • Encephalitis(inflammation of the brain)
  • Brain tumor
  • Encephalopathy
  • Sleep disorders
  • Stroke
  • Dementia
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3
Q

Name some Clinical Scenarios where an EEG may be appropriate

A
  • Carotid endarterectomy
  • Aneurysm clipping
  • CV surgery
  • Seizure observation
  • DBS surgery
  • Observation of physiologic derangement
  • Determination of brain death
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4
Q

What kind of waves are indicative of seizures on an EEG?

A

Sharp, spiking waves

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5
Q

What are slow EEG waves (delta waves) indicative of?

A
  • Tumor
  • Stroke
  • Deep Sleep
  • Anesthesia
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6
Q

Amplitude and frequency of delta waves.

A
  • High amplitude
  • Low frequency (1-4 Hz)
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7
Q

What may cause interference on an EEG?

A
  • Hypoglycemia
  • Body or eye movement during the test
  • Lights, especially bright or flashing ones
  • Benzo’s, sedatives
  • Caffeine
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8
Q

What is burst suppression?

A

When EEG shows quiet brain activity and decreased CMRO2

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9
Q

When will burst suppression be used?

A
  • May be used during aneurysm clipping
  • This will significantly reduce the brain’s metabolic rate, allow for safer manipulation of blood vessels, and minimize the risk of ischemic damage caused by clips
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10
Q

How will you induce burst suppression?

A

Bolus + Maintenance gtt Propofol

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11
Q

How will you know you are in burst suppression?

A
  • Communication with evoke techs
  • Flat tracings interspersed w/ “burst” of activity
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12
Q

What will the EEG tracing look like if you are too deep?

A

Isoelectric, zero amplitude

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13
Q

What is a Bispectral Index?

A

Data derived from EEG compressed into single measurement

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14
Q

How does a BIS monitor work?

A
  • Proprietary Algorithm
  • Use of 4 fronto-temporal EEG monitors
  • Signal over 5-10 seconds analyzed (this is called an epoch)
  • Histogram of each frequency is plotted [proprietary algorithm!]
  • Deeper anesthesia = lower frequencies dominate
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15
Q

What BIS score will indicate cortical electrical silence?

A

0

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16
Q

What BIS score will indicate normal awake cortical activity?

A

85-100

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17
Q

What BIS score will be consistent with general anesthesia?

A

40-60

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18
Q

What causes seizures?

A

Sudden uncontrolled discharge of groups of neurons

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19
Q

What transient abnormalities may single seizures result from?

A
  • Hypoglycemia
  • Hyponatremia
  • Hyperthermia
  • Brain injury
  • Drug toxicity
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20
Q

Characteristics of a Focal Seizure

A
  • Also called a “Partial” seizure
  • Start in a particular part of brain
  • Feel/see/hear things that aren’t there
  • Can be mistaken for mental illness
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21
Q

Characteristics of a Generalized Seizure

A
  • Occurs in BOTH sides of brain
  • Muscle spasms
  • LOC possible
  • Several types of Generalized Seizures
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22
Q

Characteristics of an Unknown-onset Seizure

A

May start as one kind, become another kind

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23
Q

Tonic-Clonic seizure

A
  • Grand-mal seizure
  • Full body shaking
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24
Q

Clonic seizure

A
  • Rhythmic jerking
  • Last 1-3 minutes
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25
Q

Tonic seizure

A

Sudden increase in muscle tone that causes the body, arms, or legs to become stiff or tense.

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26
Q

Atonic seizure

A
  • Part or all of the body may become limp.
  • Risk of falling, may wear a helmet
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27
Q

Myoclonic seizure

A

These seizures are characterized by short, sudden, lightning-quick jerking or twitching movements of the body.

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28
Q

Absence Seizure

A
  • Type of seizure that can cause brief lapses in awareness due to abnormal brain activity
  • Eyes roll back/staring
  • Common in kids
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29
Q

How are seizures diagnosed?

A
  • MRI
  • EEG
  • Electrocorticography
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30
Q

Treatment progression for seizures.

A
  • Single antiepileptic drug
  • Followed by drug combinations
  • Final option, surgical resection/ablation
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31
Q

MOA of Antiseizure Drugs

A
  • Reduce the inward VG positive currents, Na+ and Ca+ (Lamictal, Carbamazepine)
  • Increase GABA (Valproate)
  • Decrease Glutamate, Aspartate (Keppra)
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32
Q

Describe the MOA of Keppra

A
  • Keppra binds to SV2 (synaptic vesicle protein 2A to inhibit the release of NT)
  • Commonly given to neurosurgical patients for the prevention of seizures
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33
Q

What concerns would the anesthesia providers have with older-generation anti-seizure drugs?

A
  • CYP 450 upregulation
  • Fast metabolizers
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34
Q

Anesthetic Management to Prevent Seizures in the Neurosurgical Patient

A
  • Be aware of retraction, incision = cortical irritation. Can induce seizure activity.
  • Be aware of tumors, bleeds, fever, encephalitis, hypoxia, stroke…Can all cause seizures
  • Keppra 500-1000 mg IV
  • Hypoglycemia can cause seizures.
35
Q

Good Anesthetic Agents with Seizure Patients?

A
  • Barbiturates & Propofol
  • BZD (↑ GABA)
  • Magnesium (Inhibits glutamate)
  • Nitrous oxide
  • Ketamine – can increased CMRO2 but it may be safer used with prop or a benzo
36
Q

What induction drug can lower the seizure threshold?

A

Etomidate

37
Q

What drug has an active metabolite that can induce seizures?

A

Meperidine (Demerol)

38
Q

What is Status epilepticus?

A
  • Life-threatening medical emergency
  • Two or more seizures without return of consciousness or a continuous seizure
39
Q

Treatment for Status epilepticus?

What should be done first?

A
  • Airway and Ventilation (Priority)
  • Treatment of hypoglycemia
  • Antiepileptic anesthetics– i.e. benzos, barbs, prop
  • Arterial Blood gases
  • Muscle relaxants
40
Q

What is Multiple Sclerosis?

A
  • Autoimmune disease affecting the central nervous system
  • Damages myelin (demyelinating)
  • Interferes with nerve conduction
41
Q

Hallmark Sign of MS

A
  • Symptoms develop over a few days, remain stable a few weeks, then improve
  • Remission-Exacerbation cycle
42
Q

What age does the onset of MS usually occur?

A

After 35 (usually a slow progression)

43
Q

Symptoms that reflect site of demyelination. What is usually the first sign of MS?

A
  • Optic nerve: visual disturbance (1st sign)
  • Cerebellum: gait disturbance
  • Spinal Cord: paresthesia , weakness, incontinence
  • May see autonomic dysfunction
44
Q

Pharmacological treatment of MS

A
  • Corticosteroids: anti-inflammatory effects, help restore blood/brain barrier
  • Interferon: limited to patients with rapidly progressing symptoms. Cardiac toxicity.
  • Azathioprine: purine analogue
    Immunosuppressant
  • Methotrexate: Immunosuppressant/anti-inflammatory. Slows progression.
45
Q

Anesthetic Management: MS

A
  • Pre-operative assessment of symptoms/recent exacerbations
  • Consider stress dose, steroid coverage
  • Continue MS medications on the day of surgery
  • Note that some medication regimens for MS (immunosuppressants) can have negative effects on CV system & Liver
46
Q

Anesthesia considerations for individuals on Baclofen Pump

A
  • Increases sensitivity to NDMR
  • Use the lowest possible dose of ROC recommended
  • Avoid succinylcholine (Ach receptors may be upregulated, increase K+)
47
Q

Avoid these risk factors for MS relapse

A
  • Fever
  • Hyperthermia (Even temp increase of 1 degree can exacerbate sx)
  • Infection
  • Emotional stress – Versed pre-op!
48
Q

What is Guillain-Barré Syndrome (GBS)

A
  • Rare neurological disorder that occurs when the body’s immune system attacks the peripheral nervous system
  • Acute inflammatory demyelinating polyradiculoneuropathy
49
Q

Hallmark Signs of GBS.
What is usually the first sign?

A
  • Sudden onset of skeletal muscle weakness or paralysis
  • First sign is usually “Pins and needles”/numbness
  • Weakness begins in legs and spreads to upper body
  • Muscle denervation = upregulation of Ach receptors
  • Autonomic nervous system dysfunction
50
Q

Most serious signs of GBS

A
  • Difficulty swallowing
  • Impaired ventilation
51
Q

Symptoms of Autonomic Dysfunction

A
  • BP fluctuations
  • HTN with laryngoscopy
  • HOTN with position/positive airway pressure
  • Resting tachycardia
  • Profuse diaphoresis
  • Orthostatic hypotension
  • Sudden death
52
Q

Anesthetic Management: GBS

A
  • GETA (MAC likely not appropriate)
  • Could have airway reflex dysfunction
  • Respiratory compromise
  • Consider arterial line
  • Avoid succinylcholine, use NMDR judiciously
  • Prepare for postop ventilation.
53
Q

What are Neurodegenerative Diseases?

A

Progressive loss of structure or function of neurons

54
Q

Parkinson’s Disease

A
  • Neurodegenerative disorder of unknown cause
  • Characterized by loss of dopaminergic fibers from the basal ganglia (affecting movement)
  • Results in decreased norepinephrine production (ANS function)
  • Can cause clumps of protein: alpha-synuclein (Lewy bodies)
55
Q

What is the single most important risk factor of Parkinson’s?

A

Increased age

56
Q

Triad Symptoms of Parkinson’s

A
  • Skeletal muscle tremor
  • Rigidity
  • Akinesia
57
Q

Complications associated with Parkinson’s

A
  • Autonomic dysfunction
  • Respiratory obstruction
  • Aspiration pneumonia
58
Q

Where does muscle rigidity first appear in Parkinson’s?

A

Proximal muscles of the neck

59
Q

Movement abnormalities associated w/ Parkinson’s

A
  • Reduced arm swinging
  • Pill rolling
  • Tremors at rest
60
Q

Pharmacological treatment of Parkinson’s

A
  • Increase dopamine in basal ganglia
  • Levodopa - Crosses BBB, ↑ dopamine
  • Carbidopa - prevents Levodopa breakdown prior to reaching BBB
61
Q

Side effects of Levodopa

A
  • Dyskinesias
  • Altered myocardial contractility
  • Orthostatic hypotension
  • N/V
62
Q

Surgical Treatment of Parkinson’s Disease.

Who is it reserved for?

A
  • Deep Brain Stimulator (~70% success rate)
  • Reserved for patients with disabling and medically refractory symptoms
63
Q

Anesthetic Consideration for Alzheimer’s

A

Consider TIVA (quicker recovery)

64
Q

What is Huntington’s disease?

A
  • Rare, genetic neurodegenerative disease causing enlargement of lateral ventricles
  • Movement disorder
  • Can cause outburst and depression
65
Q

What is Amyotrophic Lateral Sclerosis (Lou Gehrig Disease)

A
  • Progressive degeneration of motor neurons
  • Will cause paralysis, respiratory failure, fatal
  • No cure, treat symptoms
66
Q

Myasthenia Gravis (MG) is an autoimmune disorder that destroys what receptor?

A

Post-synaptic nicotinic ACh receptor (as much as 80% may be loss)

67
Q

Factors that can trigger MG

A
  • Stress
  • Surgery
  • Pregnancy
68
Q

Hallmark symptoms of MG

A
  • Weakness
  • Rapid exhaustion of voluntary muscles (skeletal) followed by partial recovery with rest
69
Q

How is MG diagnosed?

A
  • Blood test
  • EMG (Electromyography)
  • Nerve Stimulation test
  • Tensilon Test (Edrophonium)
  • Check for a tumor on the thymus gland
70
Q

Pharmacological Treatment of MG

A
  • Anticholinesterase drugs: inhibit enzyme responsible for breakdown of acetylcholine = more Ach
  • Pyridostigmine
  • Neostigmine
71
Q

What are the causes of Cholinergic Crisis

A
  • TOO MUCH Ach or substances that mimic Ach
  • Dose of anticholinesterase medication is too high
  • Also caused by pesticides, nerve gas
  • Profound weakness d/t continuous depolarization of the postsynatpic membrane
72
Q

Edrophonium Effect on Myasthenic Crisis vs Cholinergic Crisis

A
  • Myasthenic Crisis improves with edrophonium
  • Cholinergic Crisis worsens with edrophonium
73
Q

Why do you want to avoid Calcium Channel Blockers with MG?

A

CCB inhibit ca2+ from entering cell; blocking nerve impulse at NMJ

74
Q

Why do you want to avoid magnesium with MG?

A

Mag causes muscle weakness

75
Q

What is indicated when skeletal weakness is not adequately treated with anticholinesterase drugs?

A
  • Immunosuppression Drugs
  • Steroids
  • Azathioprine
  • Cyclophosphamide
  • Cyclosporin
76
Q

What are the effects of short-term immunotherapy in treating MG?

A
  • Removes antibodies from circulation by plasmapheresis
  • Temporary effect but useful in preparation for thymectomy
77
Q

What is the surgical treatment for MG if there is a tumor on the thymus gland?

A
  • Thymectomy
  • Post-op 75% show improvement or remission
78
Q

Anesthetic Management: Myasthenia Gravis

A
  • High risk for aspiration
  • Pharyngeal/laryngeal muscles VERY commonly affected
  • PPI, H2 blocker, prokinetic (Reglan)
  • Extubate AWAKE
  • Continue MG medications
  • Sensitive to opioid & benzo effects… use with caution!
  • Volatile anesthetics may be sufficient for relaxation
  • Resistant to depolarizers (SUX)
  • Very sensitive to non-depolarizers (Roc)
  • Use Sugammadex
79
Q

Where do the antibodies attack in Lambert-Eaton syndrome?

A

Antibodies directed against presynaptic calcium channels at the NMJ

80
Q

What happens to muscle strength with repeated use in Lambert-Eaton syndrome?

A

Improve muscle strength

81
Q

__________ muscles are affected more in LE syndrome than in MG

A

Proximal

82
Q

Lambert-Eaton Syndrome is associated with this cancer

A

Small-cell lung cancer

83
Q

LES vs. MG Chart

A