Neurology Flashcards
pupil size in coma:
- one dilated, nonreactive or sluggish pupil
- cause
- examples
- cause: parasympathetic nerve problem
- oculomotor nerve compression from uncal herniation
- aneurysm of posterior-communicating artery
pupil size in coma:
- one pinpoint pupil (miosis)
- cause
- examples
- cause: sympathetic nerve problem (Horner)
- lateral medullary syndrome
- hypothalamus injury
- Pancoast tumor
- carotid dissection
pupil size in coma:
- two midpoint, nonreactive pupils
- cause
- examples
- cause: parasympathetic and sympathetic nerve destruction
- midbrain disruption (can affect one or both pupils)
- anoxia
- hypothermia
- anticholinergics
- severe barbituate overdose
pupil size in coma:
- two dilated, nonreactive pupils
- examples
- anoxia
- hypothermia
- anticholinergics
- severe barbituate overdose
pupil size in coma:
- two dilated, nonreactive pupils
- examples
- opiates
- pontine destruction
what is a seizure?
- paroxysmal electrical discharges of brain that cause LOC
- alteration of perception or impairment of psychic function
- convulsive movements
- disturbance of sensation
- or some combination thereof
what is epilepsy?
recurrent, unprovoked seizures
what is status epilepticus?
- prolonged or repetitive seizures
- life-threatening
what are triggers for seizures in susceptible individuals?
- alcohol
- cocaine
- intense emotions
- strobe lighting
- loud music
- stress
- menstruation
- lack of sleep
seizures are categorized into what 2 categories?
- GENERALIZED
- FOCAL
focal seizures involve how many sides of the brain, and motor activity is noted on how many sides?
- 1 hemisphere
- usually 1
generalized seizures involve how many sides of the brain, and motor activity is noted on how many sides?
- both hemispheres
- usually both, but not necessarily
focal (partial) seizures are further classified into what categories?
- simple partial: no LOC
- complex partial: LOC
- partial w/ secondary generalization
generalized seizures are further classified into what categories?
- nonconvulsive: absence seizure
- convulsive:
2a. myoclonic
2b. clonic
2c. tonic-clonic
2d. atonic
focal seizures are commonly d/t what?
focal brain lesions
primary generalized seizures are more typically d/t what?
genetics
if PNES (psychogenic nonepileptic seizures) are suspected or when the events do not respond to tx and the dx is not clear, what should be ordered?
video EEG monitoring
what percentage of pts w/ PNES (psychogenic nonepileptic seizures) also have epilepsy?
20%
what is an aura?
perceptual disturbance that may precede a FOCAL seizure
auras may precede what type of seizure?
FOCAL seizures
auras do NOT occur w/?
PRIMARY generalized seizures
how can auras manifest?
- SENSES
- MOTOR
auras are thought to be produced by?
EARLY seizure activity
describe generalized tonic-clonic seizures
- involve both hemispheres
- BILATERAL motor involvement
- LOC
- pronounced postictal period
describe absence seizures
- nonconvulsive
- no aura
- no postictal symptoms
- sudden interruption of consciousness
- can be induced by HYPERVENTILATING
- 3-per-second spike and wave pattern on EEG
what number of children outgrow absence seizures?
2/3
describe focal (aka simple partial) seizures
- no LOC
- symptoms depend on affected region of cortex
describe focal seizures w/ diminished consciousness (aka complex partial): temporal lobe type
- aura may hallucination
- altered behavior/consciousness
- amnesic
- automatisms: lip-smacking, chewing or swallowing movements, salivation, fumbling of hands, shuffling of feet
definition of status epilepticus
- seizure lasting > 30 minutes
- 2 or more seizures WITHOUT regaining consciousness in between
when should you be aggressive when treating seizures and use abortive therapy?
when seizure lasts 5 minutes or more
what are possible causes of status epilepticus?
- stroke
- alcohol
- drugs
- stopping or changing AEM’s
- hypoxia
- CNS infection
- metabolic causes
- tumor
- trauma
seizure management: history
- alcohol use
- drug use
- head injury
- sleep deprivation
- diabetes
- thyroid or parathyroid surgery
seizure management: laboratory tests
- glucose
- Na+
- Ca++
- Mg++
- transaminases
- BUN
- LP for VDRL if meningeal sxs
seizure management: best neuroimaging test
MRI (to r/o structual abnormality)
seizure management: can confirm dx of seizures and localize the origin
EEG
can a NORMAL EEG exclude the dx of epilepsy?
NEVER
after initial seizure, RISK OF RECURRENCE increases w/ the following:
- abnormal EEG
- h/o prior neurological injury
- family h/o seizures
- 1st seizure is a FOCAL seizure
- MRI shows abnormality
ACUTE TX OF SEIZURES
IV benzos
typical tx of status epilepticus in adults
- thiamine, and 1 amp of D50 if blood glucose is low
- LORAZEPAM x 2 doses
- loading dose of PHENYTOIN/fosphenytoin
tx of status epilepticus if pt continues seizing after initial tx
- 3rd dose of lorazepam
- maximize phenytoin dose
- proceed to barbiturate or propofol
- +/- ET intubation and ICU care (generally needed if first 2 doses and dose of phenytoin don’t work)
mainstay of chronic tx of seizures
AEDs, w/ monotherapy as the preferred goal
PRIMARY DRUG for: focal
carbamazepine
advantage of carbamazepine
toxicity is UNcommon
disadvantages (adverse effects) of carbamazepine
- hyponatremia
- leukopenia
- thrombocytopenia
- aplastic anemia
- hepatotoxicity
- teratogenic
- liver inducer; reduces OCP efficacy
PRIMARY DRUG for: generalized tonic-clonic
valproic acid
advantages of valproic acid
- wide spectrum
- good efficacy
- IV form available
disadvantages (adverse effects) of valproic acid
- GI side effects
- can rarely cause BM suppression and hepatotoxicity/liver failure
- teratogenic (neural tube defects)
- tremor
- weight gain
- hair loss
PRIMARY DRUG for: absence (only)
ethosuximide
disadvantage (adverse effects) of ethosuximide
BM suppression (rare)
tx for absence (short-term adjunctive use only)
clonazepam
disadvantages (adverse effects) of clonazepam
loses efficacy
advantages of levetiracetam
- well tolerated in elderly
- safe in Asian pts w/ HLA-B*1502 (increased risk of SJS)
- renally excreted so no interaction w/ levels of other AEDs
disadvantages (adverse effects) of levetiracetam
- depression
- fatigue
- irritability
- increased infections
advantages of gabapentin
- one AED w/ NO significant drug interactions
- renally excreted so useful in pts w/ liver disease
disadvantages (adverse effects) of gabapentin
- ataxia
- amnesia
- limited efficacy
advantages of lamotrigine
- wide spectrum
- good efficacy
- well tolerated in elderly
disadvantage (adverse effects) of lamotrigine
severe rash and SJS w/ rapid titration
last choice tx for focal siezures
phenobarbital
disadvantages (adverse effects) of phenobarbital
- sedation in adults
- hyperactivity in children
- teratogenic
- liver inducer; reduces OCP efficacy
- DECREASES levels of other AEDs
advantages of topiramate
- weight loss
- headache ppx if present
disadvantages (adverse effects) of topiramate
- kidney stones
- increased glaucoma
- weight loss
- paresthesias
- cognitive dysfunction
- teratogenic
- reduces OCP efficacy
which AEDs can be used to tx focal seizures?
ALMOST ALL AEDs, EXCEPT ethosuximide
tx for generalized seizures (tonic-clonic)
- TOPIRAMATE
- LAMOTRIGINE
- VALPROATE
- levetiracetam
- felbamate
- funinamide
- zonisamide
tx for generalized seizures (absence)
- lamotrigine
- ethosuximide
- valproic acid
when can you STOP AEDs?
individualized for each pt
tx options for INTRACTABLE EPILEPSY
- resective surgery
- vagus nerve stimulation
- ketogenic diet (works well in children)
which AEDs reduce OCP efficacy? (6)
- phenytoin
- phenobarbital
- carbamazepine
- lamotrigine
- oxcarbazepine
- topiramate (higher doses)
uncontrolled seizures during pregnancy can cause
- placental abruption
- early labor
- premature delivery
AEDs are still used in pregnancy bc the risk of complications from uncontrolled seizures is even GREATER than
risk of teratogenicity
tx strategy for seizures during pregnancy
- control seizures as much as possible
- MONOTHERAPY
- LOWEST DOSE possible
MOST LIKELY AED to cause NEURAL TUBE defects
valproic acid
teratogenic risk of AEDs is DECREASED by
FOLIC ACID