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66 Cards in this Set
- Front
- Back
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Partial seizures
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group of hyperactive neurons with electrical hyperactivity
restricted to one anatomical lesion |
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2 types fo partial seizures
describe them |
elementary partial (focus in motor or sensory cortex, no LOC)
complex partial (focus in temporal lobe, affecting higher brain fxn --> disturbances in psychomotor/psychosensory fxn, altered consciousness) |
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Generalized seizures
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associated with bilateral synchronous and symmetrical EEG discharge
LOC (can begin as a partial or elementary partial sezizure and eventually progress) |
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Subtypes of generalized seizures
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tonic-clonic (grand mal)
absence myoclonic infantile spasms akinetic/atonic drop attacks |
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manifestations of elementary partial seizures
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motor (frontal cortex tonic and clonic muscle activity)
sensory (hallucinations, from parietal/occipital lobes) EEG: unilat localized spiking activities, contralateral to seizure presentation) NO LOC Jacksonian march can generalize to tonic clonic |
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Who is likely to get elementary partial seizures
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post-stroke pts
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how long do elementary partial seizures last
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seconds to minutes
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manifestations of complex partial seizures
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hallucinations
GI disturbances, dizziness, urination de ja vu/ jamais vu fantasy state, memory loss automatisms |
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EEG in complex partial
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unilateral left side, seen during interictal period or sleep
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how long do complex partial seizures last
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1-2 mins
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what can cause complex partial seizures
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birth trauma
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stages of tonic clonic seizures
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prodromal (autonomic probs, change of mood, can precede by hours)
loss of muscle tone and consciousness tonic (apnea/cyanotic) clonic (1-5 mins) |
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EEG findings in tonic stage of tonic clonic
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symmetrical
bilateral |
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what happens to breathing during tonic-clonic seizures
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apnea and cyanosis during tonic
hyperventilation during the clonic |
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EEG findings in clonic stage of tonic clonic
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spike and wave complexes
bilateral and symmetrical hyperventilation |
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EEG findings in absence seizures
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oscillatory firings in thalamic neurons
mediated by low threshold ca current 3 cps spike/wave complex from thalamus bilateral and symmetrical |
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onset of absence seizures
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4-8 yo, can convert at puberty
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what can elicit absence seizures
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hyperventilation
bright light (these DON'T induce absence variant seizures) |
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what % of pts with absence seizures --> tonic clonic
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50%
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absence variant
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2-2.5 cps spike and wave
poor prognosis, assoc with dementia some motor movts |
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Minor motor seizures
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can occur at any age, but usually young
result from perm neuro damage repetitive, rhythmical, symmetrcal contractions of facial muscles and limbs |
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EEG of minor motor seizures
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polyspike and wave complexes
bilat and symm |
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Infantile spasms
Prognosis |
age specific syndrome (3 mo-2 yr)
90% --> MR 40% --> CP |
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Manifestations of infantile spasms
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flexor spasms or extremities and head for several seconds
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EEG of infantile spasms
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hypsarrhythmia
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cause of infantile spasms
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encephalopathy during development
inflammatory therapy can include ACTH/corticosteroids |
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Akinetic/atonic drop attacks
Prognosis Manifestations |
in kids 2-5 yo
poor prognosis (assoc with MR) head drooping, falling |
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EEG of akinetic/atonic drop attacks
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polyspike and wave complexes
bilat adn symmetrical vary in rhythm |
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MOA Carbamazepine
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slows rate of recovery of volatage activated Na channels from inactivation
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Pharmacokinetic issues of carbamazepine
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autoinduction of p450 --> tolerance
97% metabolic clearance |
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adverse effects of carbamazapine
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diplopia
ataxia dizziness nausea nystagmus HYPONATREMIA (from SIADH) aplastic anemia, agranulocytosis (fatal and irreversible) |
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uses for carbemazepine
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partial seizures (first choice)
tonic clonic (first choice) trigeminal/glossopharyngeal neuralgia NOT for absecne or minor motor |
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what can carbemazepine NOT be used for
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absence and minor motor seizures
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oxcarbemazepine
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pro-drug
less autoinduction --> less tolerance |
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adverse reactions to oxcarbazepine
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ataxia
diplopia SIADH |
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indications for oxcarbazepine
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partial seziures (complex and simple)
tonic-clonic trigeminal and glossopharyngeal NOT for absence or minor motor |
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advantages of oxcarbazepine
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less tlerance
fewer hypersensitivity rxns less severe interactions with polytherapy |
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phenytoin
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NOT CNS depressant
prolongs inactive state of Na channels, prolonging refractory period |
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pharmacokinetics of phenytoin
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LIMITED ACQUEOUS SOLUBILITY
BIOINEQUIVALENCE COMMON 90% met by p450 non-linear relationship btwn dose adn plasma concentrations |
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benefits of phenytoin
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less autoinduction of p450
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what drugs can displace phenytoin from albumin
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valproate
sulfonamides --> increased free phenytoin but lower total [] |
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what drugs enhance metabolism of phenytoin
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phenobarbital and carbamazepine
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adverse effects of phenytoin
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ataxia
diplopia slurred speech nystagmus confusion hypersensitivity rxn (msot common) gingival hyperplasia hirsutism vit K, D, folate deficiency TERATOGENIC!!! |
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what are the implications of phenytoin during pregnancy
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teratogenic --> cleft lip/palate, heart defect, slowed growth and mental deficiency
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indications for phenytoin
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= to carb for tonic-clonic and partial seizures
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what is used to treat recurrent tonic clonic or focal partial status epi
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IV fosphenytoin
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phenobarbital
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barbiturate with anticonvulsant activity
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mechanism of phenobarbital
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potentiates GABA effects
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pharmacokinetics
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MOST POTENT INDUCER OF P450 --> tolerance
increases metabolism of many therapeutic agents |
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Adverse effects of phenobarbital
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sedation
nystagmus and ataxia w/d vit d, k, and folate deficiency paradoxcial hyperkinesia |
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uses of phenobarbital
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partial seizures
tonic-clonic STATUS EPI NEONATAL SEIZURES NOT useful for absence, atonic, infantile |
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MOA ethosuxamide
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slows Ca curretns in thalamic neurons that discharge during ABSENCE seizures
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pharmacokinetics of ethosuxamide
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doesn't induce p450
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adverse effects of ethosuxamide
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N/V
drowsiness urticaria blood dyscrasias |
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uses for ethosuxamide
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SIMPLE ABSENCE SEIZURES
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MOA valproic acid
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prolongs recovery of Na channels from inactivation
reduces Ca currents in thalamic neurons increases GABA |
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pharmacokinetics valproic acid
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doesn't induce p450
use in combo |
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adverse effects of valproic acid
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N/V
fine tremor weight gain teratogenic --> spina bifida thrombocytopenia hepatotoxicty (fatal hepatic injury) |
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uses of valproic acidq
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FIRST CHOICE FOR ABSENCE SEIZURES
MOST EFFECTIVE FOR MYOCLONIC AND ATONIC hypsarrhthmia almost as good as carb for partial and tonic seizures |
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MOA lamotrigene
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delays recovery of Na channels
inhibits Ca channels |
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adverse rxn of lamotrigene
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skin rash (1-2% life-threatening)
toxic epidermal necrolysis |
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uses of lamotrigene
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comp to carbam for partial and tonic clonic
ABSENCE AND MYOCLONIC good for add-on if used with p450 inducers |
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pharmacokinetics
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no p450 induction
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which drugs will increase clearance of OC
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carbamazepine
phenobarbital phenytoin (these drugs also --> teratogenics) |
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which drugs --> coagulopathy
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carbamazepine
phenobarbital phenytoin all promote vit K catabolism (these drugs --> teratogenicity also) |
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drugs --> teratogenicty
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phenytoin
carbamazepine valproate phenobarbital |
