epilepsy and seizures Flashcards
Seizure vs epilepsy
Transient occurence of signs and symptoms due to abnormal excessive or synchronous neuronal activity in the brain
Epilepsy- is not one condition, but is a diverse family of disorders, having in common an abnormally increased predisposition to seizures
epilepsy
a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures and by the neurobiologic, cognitive, psychological and social consequences of this condition
To have epilepsy you need to have had one seizure
A disease of the brain defined by any of the following conditions: at least 2 unprovoked/reflex, seizures occuring >24 hrs apart
One unprovoked/reflex seizure and a probability of further seizures similar to the general recurrence risk at least 60% after 2 unprovoked seizures, occuring over the next 10 yrs
Diagnosis of an epilepsy syndrome
Acute symptomatic seizures not epilepsy
many names: provoked seizures, reactive seizure, situation- related seizures
A clinical seizure occuring at the time of a systemic insult or in close temporal association with a documented brain insult
Acute symptomatic seizures clinically
A clinical seizure occurring at the time of a systemic insult or in close temporal association with a documented brain insult
Within 1 week of: stroke, traumatic brain injury, anoxic encephalopathy, intracrania surgery
At first identification of- subdural hematoma, CNS infection, MS or other Autoimmune exacerbation
Febrile illness (38.5C)- Rare over age 5, however anytime in childhood is possible, when documented toxic/metabolic derangement within 24 hours, drug or alcohol intoxication/withdrawal, exposure to epileptogenic drugs, severe metabolic problems
Partial seizures
Partial Simple- NO alteration of awareness
Partial Complex- alteration of awareness
Complex with generalization- Alteration of awareness evolving to a convulsion
Generalized seizures
symptomatic- secondary to a known or presumed disorder of the brain, in reality all epilepsy is symptomatic, but often we just have no clue as to what /how, Stroke, tuberous sclerosis, malformation of cortical development
Idiopathic(genetic)- there is no underlying cause other than a possible hereditary predisposition, idiopathic epilepsies are defined by age related onset, clinical and electrographic characteristics asnd a presumed genetic etiology, Juvenile myoclonic epilepsy waking up epilepsy_, childhood absence epilepsy (kid just stares)
Cryptogenic-presumed symptomatic, but unknown, the confusion was often between idiopathic and cryptogenic
Generalized vs focal(partial) seizures
Generalized seizures- arising within and rapidly engaging bilaterally distributed networks
Focal seizures- originating within networks limited to one hemispheres, remember this is talking about a seizure not a pts epilepsy, pts with epilepsy may have more than one seizure type, thus may have focal epilepsy that thru multiple seizure types, engages both hemispheres
West syndrome
Triad (classic)- infantile spasms, mental retardation, hypsarrhythmia on EEG, Random high voltage 500-1000mV slow waves and spikes
Treatment- ACTH, Infantile spasms are a neurological emergency (early treatment is associated with better outcomes), consider vigabatrin (inhibits GABA degradation) for infantile spasm in TSC
Prognosis- 31% died with 1/3 of those early deaths secontary to ATH complications,
Lennox Gastaut syndrome (LGS)
onset 3-5 yrs (1-7 yrs), slightly more common in boys, development delays common, numerous etiologies but 1/3 is unknown, tonic atonic and atypical absences are classic seizures, falls (including injuries) are common, non-convulsive status occurs in up to 50%
Abnormal EEG with slow background and multifocal discharges or slow spike and wave (ictally tonic seizures with paroxysmal fast activity, atypical absences with slow spike and wave, myoclonic and atonic seizures with spike/polyspike and wave
Prognosis-Poor, 5% will die, the vast majority 90% will continue to have seizures into adulthood, the vast majority have severe neurocognitive deficits
Very treatment resistant- Clobazam and rufinamide have specific FDA indications for LGS
Childhood absence epilepsy CAE
Onset 5-7 (range is 4-10), more common in girls, neurologically normal, school issues are often seen due to the seizures themselves
EEG classically 3 hertz spike and wave #HERTZ SPIKE WAVE(can typically be precipitated by hyperventilation
Ethosuximide is classic drug but lamotrigine and valproate are also cmmonly utilixed
Prognosis is good, remission is typically by 12 yo, <10% go on to develop generalized tonic clonic seizures
Rasmussens Encephalitis aka kr syndrome
onset 5-6 years range 1-10
Neurological normal at presentation, presents with focal motor or sensory seizures (epilepsia partialis continua in 60%), deterioate to more severe seizures with alteration of awareness and convulsions in a period of weeks to months, further worsening within 3-10 months to more prolonged seizures with associated neurologic decline (classically hemiparesis along with heminopia and neurocognitive issues)
Later in course seizures tend to burn out but deficits typically persists
MRI- progressive hemiatrophy (often temporal or insular early on), EEG- may be focal or multifocal
Prognosis- poor with treatment seizures and significant neurologic deficit, Treatment AEDs are poor responsive, results with immunomodulation are unconvincing (early is better, younger is better
Juvenile myoclonic epilepsy (JME)- JANZ syndrome
Onset- myoclonus 14-15 (range 8-26), tonic-clonic seizures after onset of myoclonus, absence- 10 years (range 5-16) often unnoticed
Presumed polygenic complex inheritance, neurologically normal, myoclonic jerks on awakening are classic, myoclonic-tonic-clonic seizures (convulsion preceded by myoclonus)
Prognosis- seizures are lifelong but improvement after 40 yrs of age is common, majority are controlled with medication, patients with all 3 seizure types are more likely to be resistant, treatment with broad spectrum AEDs, clonazepam is particularly effective for myoclonus and lamotrigine may worsen myoclonus
Progressive myoclonic epilepsy syndromes
unverricht-lundborg disease
Lafora body disease, myoclonic epilepsy with ragged-red fibers (MERRF), neuronal ceroid lipofuscinoses, sialidosis, dentato-rubro-pallido-luysian atrophy (DRPLA), Initial presentations may look like a more typical generalized epilepsy, classically have very large somatosensory evoked potentials
Landau kleffner syndrome
AKA acquired epileptic aphasia, onset 3-6 yrs
More common in boys, Hallmark is development of language problems (often starts with not responding to words, cognitive/behavioral issues may also develop, seizures are reported in about 75%), EEG classically with posterior temporal epileptiform discharges, Continuous spike and waves during slow wave sleep is typically seen, also can be called electrical status epilepticus of sleep or ESES
prognosis is poor- Seizures if present typically remit by 115, EEG typically normalizes by 15, language and cognitive issues resolve completely in only 10-20%, remainder typically with severe sequalae
Treatment- AEDs to treat seizures, often to treat spikes as well, surgical treatments are reported (even in cases without Seizures)including utilizing multiple subpial transections (MSTs)
LANGUAGE
Hypothalamic Epilepsy
Present from birth to 3 yrs, more common in boys, hallmark is gelastic Laughing seizures but also with dacrystic (crying) seizures- both lack the emotional content, dacrystic seizures are relatively uncommon 13%, hypothalamic hamartoma seen on imaging, EEG interitally is often normal or non-lateralizing (ictally low voltage suppression is common), often resistant to treatment with AEDs, surgery is often recommended- has been done with laser ablation including
Status epilepticus
continuous seizure actavity for more than 30 minutes
With or without impaired consciousness (30 minutes–estimate of duration necessary to cause neuronal injury)
Also included- recurrent seizures- no complete recovery of consciousness between attacks
Emergency- neuronal injury in 30mins
> 5 mins in adults of seizure
generalized convulsive status epilepticus
Most common 75%
Treatment- erarly and aggressive
ABCs- Airway breathing and circulation
Lorazepam, fosphenyton, Valproate and levetricatem, lacosamide
Treatment general measures
Avoid hyperglycemia as this can exacerbate neuronal damage, treat hypotension and hypeerpyrexia, intubation when necessary if not 100% O2, EEG monitoring for pts who require prolonged NM blockade, remain unconscious following termination of seizure activity, or require prolonged treatment for refactory se
Once pt stabilized, search for etiology
Epilepsy treatment strategies and mechanisms
general strategies (decrease excessive rates of neuronal discharge within a focus), prevent propagation of seizure activity from the focus to other regions
Basic mechanisms for antiseizure drugs- affect abnormal membrane function (changes in voltage regulated ion channels that lead to depolarization)
Correct decreased inhibition - increase GABA, reduce excitation (block glutamate receptors)
oral and metabolism is high
Phenytoin
MOA- alters ion conductance, use dependent effect on sodium channels, inhibits the generation of repetitive action potentials, Locks the inactivation gate
Pharmacokinetics-dependent upon drug formulation, highly protein bound, pharmacokinetics are dose dependent, usual therapeutic level 10-20 ug/ml
Clinical use- Generalized tonic clonic seizures, focal seizures
SE- may interact with drugs that are metabolized by microsomal enzymes and drug that are protein bound
Tox- CNS dose dependent, nausea, anorexia, apathy, sedation, ataxia, nystagmus, and diplopia, gingival hyperplasia, hirsutism, teratogenicity - fetal hydantoin syndrome- cariac defects cleft palate, hypersenstivity reaction - rash
Fosphenytoin- water soluble phentoin anolog, used IV in status epilepticus
Carbamazepine
MOA- Blocks Na channels at therapeutic concentrations, Similar to phenytoin, Does not appear to interact with GABA systems
Pharmacokinetics- unpredictable absorption, hepatic enzyme induction
Toxicity- diplopia and ataxia, GI upset, drowsiness, blood dyscrasias (rare and not dose dependent) can be fatal, hyponatremia, teratogen
Relatives- Oxcarbazepine (newer analog improved side effect, less hepatic induction), Eslicarbazepine (newest analog, pure active isomer, both associated with hyponatremia
Phenobarbital
oldest prescription anti seizure medication, Enhances action of GABA at GABA a receptors, effective in most types of seizure disorder, including focal, tonic- clonic, and myoclonic seizures
Use is limited by sedation
Childhood absence epilepsy CAE
Onset 5-7 (range 4-10), more common in girls, neurologically normal , School issues are often seen due to the seizures themselves
EEG classically 3 hertz spike and wave, can typically be precipitated by hyperventilation
Ethosuximide
Drug of choice for absence seizures
MOA- Reduces low threshold (T type) calcium currents in thalamic neurons
Pharmacokinetics- well absorbed after oral administration, not protein bound, liver metabolism- inhibited by valproate, long half life
Toxicity- GI distress twice daily dosing can help, lethargy, fatigue
Clinical use- absence seizures, not useful in other seizure types
Valproate
MOA- Blocks repetitive neuronal firing, may reduce T type calcium currents, increases GABA concentrations
Pharmacokinetics- bound to plasma protein (competes with phenytoin), distributes in extracellular fluid P450 inhibitor- inhibts metabolism of phenobarbital, phenytoin, and carbamazepine
Toxicity- GI distressm fatigue, weight gain, hairloss, heptotoxicity teratotogenicity, avoid use in women of child bearing age
Clinical use- broad spectrum
Felbamate
acts at the glycine modulatory site on the N- methyl-d aspartate (NMDA) receptor- antagonist, also potentiates GABA,
Used for focal seizures that are refractory to other agents, use is limited by the occurence of aplastic anemia, and hepatic failure to seizurres refractory to other drugs
Gabapentin
Analog of GABA, role of GABA in its action is not clear, it is not a GABA agonis, Adjuct therapy in the treatment of focal seizures with or without secondarily generalized tonic- clonic seizures
Gabapentin is not metbolized and has no protein binging making it devoid of the usual drug interaction, may produce lower extremity edema, also used for neuropathic pain and ALs
Pregabalin
more potent form of gabapentin
May produce lower extremity peripheral edema
May interact with alpha 2 - delta subunit of voltage gated calcium channels reducing neurotransmitter release
Indicated for- Adjunctive therapy for focal seizure, management of neuropathic pain associated with diabetic peripheral neuropathy and postherpetic neuralgia and fibromyalgia
DEA schedule 5 drug- very limited abuse potential
Lamotrigine
Blocks repetitive action potentials and may block Na channels, used for focal, generalized tonic- clonic and absence (Not FDA approved) seizures including monotherapy
Approved for bipolar disorder
Does not interfere with pharmacokinetics of other drugs
May cause serious rash including Stevens Johnson syndrome
Topiramate
Derived from D-fructose, inhibts excitatory transmission by antagonizing the ability of excitatory amino acids to activate the kainate AMPA subtype of glutamate receptor, may also block sodium channels similar to phentoin
Blocks the spread of seizures rather than raise the seizure threshold
Used as add- on therapy of adults with focal seizures
Also used for prevention of migraines, side effects include fatigue, nausea, and confusion
Can cause weight loss and is a component, along with phentermine of a combination, diet drug that is now being marketed
Tiagabine
inhibits the GABA transporter, GAT 1, and thus reuptake of GABA, increased GABA in synapse
Add on treatment for both complex and simple focal seizure, rarely used, the principal adverse effects include dizziness, tremor and somnolence
Levetiracetam
Used as adjuctive therapy for focal seizure, also indicated for adjunctive treatment of myoclonic seizure and primary generalized tonic clonic
MOA- idk
Few interactions with concomitantly administered anti seizure agents
Side effects include somnolence, asthenia and dizziness, brivaractam, more potent analog
Zonisamide
acts at both sodium and calcium channels, it reduces the voltage dependent transient inward currents (t-type calcium currents)
Stops the spread of seizures and suppresses their focus
CNS adverse reactions such as ataxia, anorexia, nervousness, fatigue and speech impairment are common and can limit the usefulness of the drug in some patients, approved for adjunctive treatment of adults with focal seizures
Lacosamide
Enhances slow inactivation of voltage gated sodium channels (in contrast to the prolongation of fast inactivation shown by some other AEDs) the antiseizure effects and the CNS side effects of lacosamide are additive to those of established AEDs acting by prolonging inactivation of the Na cahnnel
Approved for adjunctive treatment of focal seizures
Perampanel
Orally active antagonist approved for the treatment of focal and primary genralized tonic clonic seizures,
MOA- post synaptic AMPA receptors
