Neuroanesthesia Pt. 3 (Exam I) Flashcards
Sharp spiking waves noted on an EEG would make the CRNA consider what phenomenon occuring to the patient?
Seizures
Delta waves noted on an EEG would make the CRNA consider what phenomenon occurring to the patient?
- Deep Sleep (or Anesthesia)
- Tumor
- Stroke
What are characteristics of delta waves?
- 1-4 hz
- High amplitude
- Low frequency
What things can cause interference in an EEG reading?
- Hypoglycemia
- Body/Eye movement
- Lights (bright & flashing)
- Sedatives
- Caffeine
Why is burst suppression done during aneurysm clip placement?
- Increases exposure
- Decreases pressure around aneurysm
- ↓ CMRO₂ = brain protection
What is an analyzed EEG signal over 5-10 seconds called?
an epoch
BIS Values:
85 - 100 = ?
40 - 60 = ?
85 - 100 = Normal awake cortical activity
40 - 60 = Consistent w/ GETA
Single seizures (meaning one-off episodes of seizures) may result from transient abnormalities such as….
- Hypoglycemia
- ↓Na⁺
- ↑Temp
- Brain injury
- Drug toxicity
What seizure class can be mistaken for mental illness due to feeling/seeing/hearing things that aren’t there?
Focal Seizures
What’s another name for focal seizures?
Partial Seizures
What seizures are characterized by affecting both sides of the brain and muscle spasms?
Generalized Seizures
What are the subcategories of generalized seizures?
- Tonic-Clonic (Grand Mal)
- Clonic
- Tonic
- Atonic
- Myoclonic
- Absence (Petite Mal)
What age group is at higher risk for petit mal seizures?
Children
Clonic seizures are defined by…
rhythmic jerking
What generalized seizure disorder subtype has the highest risk of falling?
Atonic
Which anti-seizure drugs reduce influx of Na⁺ & Ca⁺⁺ ?
- Lamotrigine (Lamictal)
- Carbamazine (Tegretol)
Which anti-seizure drugs increase GABA?
Valproate
Which anti-seizure drugs decrease excitatory neurotransmitter activity?
Levetiracetam (Keppra)
How does Keppra work?
Decreased glutamate & aspartate activity by binding to SV2A (synaptic vesicle 2A)
What two drugs should be avoided in order to prevent seizure occurrence in neuro patients?
- Etomidate (possibly lowers seizure threshold)
- Meperidine
What anesthetic drugs are best for seizures?
- Propofol
- Barbiturates
- Benzodiazepines
- Mg⁺⁺
What metabolite of meperidine can build up and cause seizures?
Normeperidine
What is status epilepticus?
- Two or more seizures without a return to consciousness
- Continuous seizure activity
Life-Threatening Emergency
What is the treatment for status epilepticus?
- Airway & Ventilation
- Treat hypoglycemia
- Anti-epileptic anesthetics (prop, barbs, bnzos)
- Muscle relaxants
Which common autoimmune disease affects the CNS via demyelination?
Multiple Sclerosis
What gene is MS inherited from?
Trick question. Not directly inherited
What disease is characterized by the following:
- Inflammation
- Demyelination
- Axonal damage in the CNS specifically
Multiple Sclerosis (MS)
MS is typically a ___ progession, with onset most common after the age of ______.
slow progression : age of 35
What demyelinating disease is characterized by symptom development over a few days then stabilization and then temporary improvement?
MS
What is a common 1st sign of multiple sclerosis? Why?
Visual disturbances from optic nerve demyelination
How efficacious are drugs for MS?
Decrease duration of MS relapse but don’t really alter disease progression
What drugs are commonly used for MS?
- Corticosteroids
- Interferon
- Azathioprine
- Methotrexate
How do corticosteroids treat MS?
- Anti-inflammation
- Restoration (to a degree) of the BBB
What patients are candidates for interferon for treatment of MS? Why?
- Rapidly progessing disease
- Cardiac toxicity
*
What type of drug is azathioprine?
Purine analogue immunosuppressant
How does methotrexate treat MS?
Slows progression through immunosuppression/anti-inflammatory effects.
Should MS medications be continued on the day of surgery?
yes; typically
What is the anesthetic relevance of baclofen pumps for MS patients?
Baclofen will increase sensitivity to non-depolarizing paralytics.
What paralytic should be avoided in MS patients? Why?
Succinylcholine
Due to upregulation of extrajunctional ACh receptors
What are risk factors for MS relapse? (that anesthesia can help regulate)
- Fever / Hyperthermia
- Infection
- Emotional stress (consider versed pre-op)
What is another name for Acute Inflammatory Demyelinating Polyradiculoneuropathy?
Guillain Barre Syndrome (GBS)
Guillan Barre Syndrome (GBS) is oft preceded by an _______.
infection
What is often the 1st sign of GBS?
“Pins & needles” and numbness
In GBS, weakness begins in the _____, and then spreads to the ______.
begins in the legs and then spreads to the upper body
What are the most serious signs associated with GBS?
- Difficulty swallowing
- Impaired ventilation
What drug should absolutely be avoided in GBS? Why?
Succinylcholine due to upregulation of ACh receptors
Autonomic dysfunction is possible in GBS but not MS. T/F?
False. Autonomic dysfunction can occur in both
When is hypertension seen with a GBS patient during an anesthetic case?
Laryngoscopy
What aspect of anesthesia tends to cause hypotension seen with a GBS patient during an anesthetic case?
Positive airway pressure
What kind of anesthetic technique is likely inappropriate for GBS patients? Why?
MAC
- Likely to have airway reflex dysfunction & respiratory compromise
What paralytic should be avoided with GBS?
Succinylcholine
What are the three components of Parkinson’s Disease process?
- Loss of dopaminergic fibers of the basal ganglia
- ↓ NE production
- Lewy Body development
What causes the movement disorder aspect of Parkinson’s?
Loss of dopaminergic neurons of the basal ganglia
What is the name for the α-synuclein clumps of proteins developed in Parkinson’s disease?
Lewy Bodies
What is the most important risk factor for development of Parkinson’s Disease?
Age
What acronym showcases the sign/symptoms associated with Parkinson’s?
TRAP
Tremors
Rigidity
Akinesia
Posture
Where, regionally, does muscle rigidity in Parkinson’s patients first appear?
Proximal muscles of the neck resulting in “loose arm swinging”.
How are the tremors of Parkinson’s disease usually characterized?
- Pill-Rolling = Rhythmic w/ alternating flexion/extension of digits.
- Shaking that usually starts on one side
Tremors in Parkinson’s disease are usually more prominent when moving. T/F?
False. Tremors more prominent at rest.
Is there an autonomic dysfunction component to Parkinson’s? What is the result?
Yes; results in the following being more common:
- Respiratory obstruction
- Aspiration pneumonia
What are the two treatment goals with Parkinsons?
- Increase Dopamine in basal ganglia
- Decrease effects of excess ACh
How do Levodopa/Carbidopa work?
- Levodopa - crosses BBB and forms into dopamine
- Carbidopa (decarboxylase inhibitor) prevents levodopa breakdown prior to crossing of BBB.
What are the side effects of Levodopa/Carbidopa?
- Dyskinesias
- Altered heart contractility
- Orthostatic Hypotension
- N/V
What is the success rate for surgical treatment (DBS) of Parkinson’s disease?
What patients are candidates for surgical treatment?
- 70%
- Reserved for patients w/ disabling & medically refractory symptoms
What type of anesthesia should be considered with patients w/ dementia?
TIVA
Huntington’s Disease is a _______ disorder that is characterized by enlargement of the ____________.
Movement disorder (genetic)
Enlargement of lateral ventricles
ALS is a disorder characterized by what?
Amyotrophic lateral sclerosis
Disorder characterized by progressive degeneration of motor neurons.
What is the pathophysiology of myasthenia gravis?
Destruction of nACh receptors at the NMJ
What are common triggers for development of myasthenia gravis?
- Stress
- Surgery
- Infection
- Pregnancy
What are the hallmark symptoms of MG?
- Weakness (centrally first then peripherally)
- Rapid exhaustion of skeletal muscles followed by partial recovery with rest.
How is MG diagnosed?
- Blood Test
- Edrophonium (Tensilon) test
- EMG nerve stimulation
What autoimmune disorder may result from a tumor forming on the thymus gland?
Myasthenia Gravis (MG)
What type of drug is edrophonium?
Rapid-acting anticholinesterase medication
Have atropine available.
What occurs with a tensilon test?
Edrophonium is given to a patient with presumed MG, if symptoms improve then MG is diagnosed.
What other disorder may be diagnosed with a Tensilon test (other than MG) ?
Lambert Eaton Myasthenic Syndrome
How is myasthenia gravis treated?
Anticholinesterases
- Pyridostigmine
- Neostigmine
Make more ACh available at NMJ.
What is the pathophysiology of cholinergic crisis?
Excess ACh from:
- Too much AChesterase inhibitors
- Pesticides
- Nerve gas (Sarin)
What is the deadliest symptom associated with severe cholinergic crisis?
Profound muscle weakness/ flaccid paralysis
Due to continuous depolarization of postsynaptic membrane.
What acronym describes cholinergic toxicity?
Salivation
Lacrimation
Urination
Defecation
GI Upset
Emesis
Myasthenic Crisis vs Cholinergic Crisis Chart
What drug can be used to differentiate Myasthenic vs Cholinergic Crisis?
Edrophonium
- Edrophonium improves Myasthenic crisis
- Edrophonium worsens Cholinergic crisis
What drugs should be avoided (besides succinylcholine) in MG patients?
- CCBs
- Mg⁺⁺
When are immunosuppressants indicated for MG treatment?
When skeletal muscle weakness is not adequately treated with AChe inhibitors.
How does plasmapheresis treat MG? Is this permanent?
Plasmapheresis removes antibodies attacking the NMJ from the blood.
Purely a temporary measure.
What surgery is used to treat MG?
Thymectomy
Treatment of choice for majority of MG patients, 75% show improvement or remission.
What type of extubation is required for MG patients? Why?
Awake extubation due to ↑ risk of aspiration
MG patients are resistant to _______ paralytics but sensitive to _______ paralytics.
Resistant to succinylcholine
Sensitive to Non-depolarizing paralytics
Consider using VAA for muscle relaxation.
Where do antibodies attack in ELMS (Eaton-Lambert Myasthenic Syndrome) ?
Presynaptic Ca⁺⁺ channels at the NMJ
With ELMS, muscle strength improvement occurs with….
repeated use
ELMS is associated with what type of lung cancer?
Small-cell lung cancer
ELMS patients are sensitive to _______ paralytics.
Non-depolarizing
Proximal muscles are more effected in ________ than in MG.
ELMS
Are reflexes increased or decreased in ELMS?
Decreased
Is autonomic dysfunction a component of ELMS?
yes
MG vs ELMS Chart
Is autonomic dysfunction a component of MG?
No
