Brain 5 Flashcards
In patients with seizure disorders, these three drugs increase EEG activity and can be used to help determine the location of seizure foci during cortical mapping
methohexital, etomidate, alfentanil
There are several case reports of _________-induced seizures and ___________. Although it is a first-line agent for the control of acute seizure activity.
propofol-induced seizures and opisthotonos (rigid posture with an arched back)
_________ metabolism yields ______________, a proconvulsant.
Atracurium metabolism yield laudanosine
(cisatricurium produces laudanosine in a much smaller amount)
__________ is a metabolite of __________ and is capable of producing seizure activity.
Normeperidine is a metabolite of meperidine
Define status epilepticus.
seizure activity that lasts >30 min or 2 grand mal seizures without regaining consciousness in-between
Acute treatment of status epilepticus is
phenobarbital, thiopental, phenytoin, benzos, propofol, and even GA
Patients with status epilepticus can experience
respiratory arrest–> hypoxia
due to increased oxygen consumption d/t increased brain activity and muscle contraction
______ seizures are more common in children
Akinetic
Akinetic seizures result in
a temporary LOC and postural tone
The concern with akinetic seizures is
can result in a fall–> head injury
An absence seizure is
temporary loss of awareness (but remains awake)
more common in children
Define a focal cortical seizure.
localized to a particular cortical region
-can be motor or sensory
-usually no LOC
What is a grand mal seizure?
characterized by generalized tonic-conic activity
can result in respiratory arrest–> hypoxia
What is a tonic phase?
whole body rigidity
What is a clonic phase?
repetitive jerking motons
Surgical tx. for grand mal seizures includes
vagal nerve stimulator or resection of foci
Acute treatment for grand mal seizures includes
propofol, diazepam, and thiopental
Which drug is excreted unchanged by the kidneys?
a. phenytoin
b. gabapentin
c. carbamazepine
d. valproic acid
B. gabapentin
it’s elimination is dependent on renal function
Phenytoin ________ hepatic enzymes which contributes to _________ to nondepolarizing neuromuscular blockers
induces; resistance to
Extravasation or arterial injection of phenytoin can cause. _________ avoids this risk
significant tissue injury; Fosphenytoin
Valproic acid _________hepatic enzymes.
Inhibits
Valproic acid can cause
hepatotoxicity and thrombocytopenia (risk of surgical bleeding)
Carbamazepine ____________ hepatic enzymes.
induces
Carbamazepine can cause
aplastic anemia, thrombocytopenia, liver dysfunction, and hyponatremia
Gabapentinoids (gabapentin & pregabalin) _______ hepatic enzymes
do not induce; UNDERGO renal excretion instead
Gabapentinoids can cause
postoperative respiratory depression especially when combined with opioids
Gabapentinoids are useful for
neuropathic pain syndromes (diabetic neuropathy, postherpetic neuralgia, and complex regional pain syndrome)
The mechanism of action of phenytoin is
blocks voltage-gated Na+ channels- membrane stabilizer
What operation of kinetics does phenytoin follow?
zero order kinetics
The therapeutic level of phenytoin is
10-20 mcg/mL
Side effects of phenytoin include
dysrhythmias/hypotension (if IV rate >50 mg/min)
gingival hyperplasia
aplastic anemia
Stevens-Johnson syndrome
birth defects
cerebellar-vestibular dysfunction (nystagmus, ataxia)
The mechanism of action of valproic acid is
blocks voltage-gated Na+ channels- membrane stabilizer
The mechanism of action of carbamazepine is
blocks voltage-gated Na+ channels- membrane stabilizer
The mechanism of action of gabapentinoids is
inhibition of alpha 2-delta subunit of voltage-gated calcium channels in the CNS–> decreased excitatory neurotransmitter release
The most common side effects gabapentinoids include
dizziness
somnolence
Abrupt withdrawal of gabapentinoids can produce
seizures if the patient has a history of seizures (taper for at least 1 week)
The duration of action of which drug will be prolonged in the patient treated with donepezil for Alzheimer’s disease?
a. rocuronium
b. vecuronium
c. succinylcholine
d. cisatricurium
c. succinylcholine
Alzheimer’s disease is a
chronic degenerative condition of the CNS
Alzheimer’s disease is the most common cause of ________ in patients 65 years and older
dementia
Signs and symptoms of Alzheimer’s disease include
memory loss, apraxia, aphasia, and agnosia
The pathophysiology of Alzheimer’s disease includes the development of
diffuse beta-amyloid rich plaques and neurofibrillary tangles in the brain
The treatment for Alzheimer’s is
palliative and aims to restore the concentration of Ach, this is accomplished with cholinesterase inhibitors
Examples of cholinesterase inhibitors include
tacrine, donepezil, rivastigmine, and galantamine
Cholinesterase inhibitors increase the duration of action of ___________, although the clinical significance of this is debatable.
Succinylcholine
Patients with Alzheimer’s disease are often
confused, scared, and uncooperative, thus making them poor candidates for MAC or regional anesthesia with or without sedation
Consequences of plaque formation include
dysfunction synaptic transmission (most common in Ach neurons)
apoptosis (programmed cell death)
Describe the anesthetic management for patients with Alzheimer’s.
use shorter-acting drugs with general anesthesia to allow for patient to return to baseline cognition as soon as possible
preoperative sedation can worsen confusion so should be avoided
if an anticholinergic is required, glycopyrrolate is the best option since it does not cross the BBB
cholinesterase drugs increase PNS tone so s/sx of parasympathetic excess can develop (bradycardia, syncope, n/v)
Some of the ______________ increase beta-amyloid production
halogenated anesthetics (halothane & isoflurane)
Some studies suggest that ________________________ & ____________________ increase the rate of apoptosis in the brains of the very young and the very old
NMDA receptor antagonists and GABA agonists
