Seizure Disorders Flashcards
Seizure
. Stereotyped episode involving altered sensory, motor, ANS function, and consciousness
. Location and spread in brain determines how it presents
. Due to abnormal and excessive electrical discharges w/in brain
. Diagnosed based on behavioral evidence and EEG
Epilepsy
. Spontaneous recurrent seizures with no cause
. Usually can lead normal lives, but 38% suffer sudden unexpected death in epilepsy (SUDEP)
Partial (focal) seizures
. Begin in restricted brain region and remain localized or spread to djacent cortical areas
. Most common form
Simple partial seizures
. No loss of consciousness
. Abnormal electrical activity localized
. Presentation shows brain region involved
. EEG will appear normal w/ abnormal activity recorded in 1 or 2 areas
Complex partial seizure
. Loss of consciousness
. Abnormal electrical activity localized
. Simple motor activities done during seizure
. Upon recovery patient is not always aware they were doing a specific action
. May be preceded by aura
. Temporal lobe/psychomotor seizures under of nomenclature
. EEG shows focal spikes in temporal lobe areas
Partial seizures w/ secondary generalization
. Loss of consciousness
. Abnormal electrical activity spreads from seizure focus
. Intense motor activity
. Can progress to most or all of the brain
. In this case patient losses consciousness and has convulsions
Generalized seizures
. Involves entire cortex
Absence seizures
. Loss of consciousness
. A Rona last electrical activity through brain
. No convulsions or loss of postural control
. Sudden brief lapses
. Usually diagnosed in school age kids
. Used to be called petit-mal
. EEG shows spike and dome shapes at freq. of 3-4 per second (characterize abnormal synchrony)
. All pairs of electrodes record abnormal activity
Generalized tonic-clinic seizures
. Grand-mal
. Loss of consciousness suddenly
. Abnormal electrical activity through entire brain
. Tonic and clonic phases
. Toncis phase: contraction of mm. Including expiratory mm. Accompanied by cry
. May become cyanotic
. Clonic phase: limbs move rhythmically and person can breathe again
. Person may attempt to swallow tongue
. Gradual return to consciousness after that
. EEG shows excessive neuronal discharge in cortex and even spinal cord w/ hug spikes at very high frequency
Status epilepticus
. Situation when a type of seizure inc on tiny outs and there is no period of recovery period the next one
. Serious condition and can be life-threatening in tonic-clonic seizures
Cause of epilepsy
. 62% unknown . Stroke and head trauma . Alcohol . Neurodegenerative disease . Static encephalopathy . Brain tumors . Infection
Drug types that can cause seizures when high doses given over long periods of time
. CNs stimulates (amphetamines and analeptics)
. Cardia antiarrhythmic drugs (lidocaine)
. Drugs used to treat bipolar (Li)
. Antibiotics (penicillin)
Age groups seizures are more common in
Infants and adults over 60
Causes of seizure in newborns
. Congenital malformation . Perinatal hypoxia/ischemia . Trauma (intracranial birth injury) . Metabolic disturbance (hyperglycemia, hypoatremia, etc) . Genetic . Intracranial hemorrhage . Maternal drug use
Seizure causes for children
. Fever
. Acute infection
. Brain tumors
. Can also occur in infants
Causes of seizure in both children and adults
. Congenital condition (downs, angelman’s, tuberous sclerosis, neurofibromatosis)
. Genetic
. Head trauma
. Progressive brain disease
Seizure causes in seniors
. Stroke
. Metabolic disorders
. Alzheimer’s
. Head trauma
Penicillin cause for causing seizures
. High doses block GABA action
2 primary excitatory NTs
. Glu
. Aspartate
Benzos and barbiturates effect in neurotransmitters
. Binding of drugs to GABAa receptor (Cl channel) enhances effect of GABA on opening channel
. Explains widespread inhibitory effects of these drugs
. May be of some use in preventing seizures
. Benzos bind to gamma subunit of channel
. Barbiturates bind to beta subunit of channel
Strychnine
. Poisonous plant
. Blocks inhibitory action of Gly in spinal cord
. Produces tonic mm. Spasms that can cause asphyxiation from tonic contraction of respiratory mm.
. Muscle spasms result of disinhibited spinal reflexes
. Not considered true seizure of cerebral origin since it is from spinal cord
Treatment goals of epilepsy
. Prevent or reduce excessive firing from damaged or abnormal neural tissue
. Prevent or reduce spread of excessive firing to normal neural tissue
. Most drugs target the spreading portion of goal
Monotherapy vs polytherapy in epileptic treatment
. 70% patients become seizure free w/ single drug
. Many of polytherapy w/ 2nd generation or taking 3 meds w/ a 3rd generation med
. Some patients develop drug-resistant seizures (refractory epilepsy)
. Narrow spectrum drugs only good for focal seizure
. Broad spectrum drugs used in adults no matter what type fo seizure
Traditional anticonvulsants
. Benzos . Phenobarbital . Phenytoin . Carbamazepine . Valproate . Act by potentiating effects of GABA by enhancing Cl channel opening or by inhibiting GABA reuptake
benzo antagonists
. Prevent GABA enhancement but do not reduce basal Cl current
. Prevent gating of Cl channels even in presence of benzos
Other drugs that inhibit GABA
. Vigabatrin: inhibit GABA degradation
. Tiagabine: inhibit GABA reuptake
. Gabapentin: unclear on how it works though
What do newer antiepileptic drugs target?
. excitatory AAs (NMDA, AMPA, and kainate classes of Glu receptors)
. Offer fewer drug interactions, unique methods of action, and broad spectrum activity
. Voltage-dependent ion channel blockage, enhancement of neurotransmission, and reduction of excitatory NTs
Surgery for seizures
. Useful treatment for seizures from tumors and localized epileptic sources
. Severing corpus callosum as last resort for seizure patients
Vagus n. Stimulation as seizure treatment
. Used for patients w/ recurring partial seizures and have been unresponsive to meds
. Works by electrically stimulating vagus n. In neck
. Stimulates inhibitory parts of brain
. Long-term effectiveness still needs to be determined
Ketogenic diet as seizure treatment
. Has anticonvulsant effects similat to that of starvation
. More useful for children
Medical weed as seizure treatment
. CBD could be useful for seizures
. Currently sued to treat 2 rare childhood epilepsy syndromes
