Adult Seizure disorders Flashcards
Seizure?
Episode of abnormally synchronized and high frequency firing of neurons resulting in abnormal behavior or experience
Epilepsy?
Chronic brain disorder of various etiologies characterized by recurrent, unprovoked seizures
Causes of adult onset epileptic seizures?
Cerebrovascular disease Trauma Tumors Infections Cerebral degeneration
Types of partial seizures?
Simple
Complex
Secondarily generalized
Is consciousness preserved in simple partial seizures?
Yes
Is consciousness preserved in complex partial seizures?
No
Characteristics of secondarily generalized?
Consciousness lost
Bilateral cerebral involvement
Characteristics of simple partial seizures?
Consciousness is intact
EEG may appear normal
Auras are brief
Signs/symptoms of simple partial seizures depend on?
Focus
- Motor (Jacksonian)
- Somatosensory
- Autonomic
- Psychic
What is a Jacksonian march?
A focal seizure that starts distally and marches proximally on the same side
Seen in simple partial seizures emanating from motor cortex
How do somatosensory partial seizures present?
Focus on the sensory cortex
Tingling and numbness of an extremity or side of face
Autonomic partial simple seizures present?
Rising epigastric sensations, nausea
Psychic partial simple seizures present?
Sensations of fear
Deja vu
Jamais vu
Characteristics of complex partial seizures?
Impaied consciousness Lasts about 1 minute Blank stare Oral/Ipsilateral hand automatisms Contralateral dystonic posturing Amnesia for ictal event Focal abnormality on routine EEG
Where do complex partial seizures typically emanate from?
Temporal or frontal lobes
What are typical hand automatisms?
Hand rubbing and picking movements
What are oral automatisms?
Chewing and lip smacking movements
What does contralateral dystonic posturing result from?
Spread of seizure activity from the temporal lobe to the ipsilateral basal ganglia
Types of Primary generalized seizures?
Absence (Petit Mal) Tonic-clonic Clonic Tonic Myoclonic Atonic
Pathogenesis of primary generalized seizures?
Arise from deep structures within the brain and spread synchroniously toward cerebral hemispheres
Characteristics of Absence Seizure?
Brief (10-20 secs) loss of consciousness
Staring spell
NO post-ictal confusion
Subtle myoclonic movement, eyelid flutter
NO baseline neurologic defictis
Baseline EEG may show generalized 3 Hz spike - wave discharge
What is pathognomonic for absence seizures?
Baseline EEG may show generalized 3 Hz spike - wave discharges
Most recognized seizure?
Tonic-Clonic
Presentation of Tonic-clonic seizure?
Cry Loss of consciousness Muscular rigidity (tonic) Patient may fall Rhythmic jerking (clonic) Tongue-biting/injury common Bladder/bowel incontinence Post-Ictal confusion/sleep
Presentation myoclonic seizures?
Brief, shock-like muscle contractions -Head -Upper extremities Usually bilaterally symmetrical Consciousness preserved Precipitated by awakening or falling asleep May progress into tonic-clonic seizures Have trouble shaving/drinking coffee in the morning
Presentation of Atonic Seizures?
Impaired consciousness Loss of muscle tone Head drop Fall (if standing and injury is common) Brief duration (few seconds) Injury common
Ligand-gated ion channels are either excitatory or inhibitory depending on?
Ion selectivity
What does GABA activate? That do?
GABAa Receptors that mediate fast synaptic inhibition (IPSP) by permitting rapid influx of Cl ions –> hyperpolarization
What does glutamate activate? That do?
3 classes of ion channels (AMPA, Kainate, NMDA) that mediate fast synaptic excitation by permitting a rapid influx of Na and Ca
When does a seizure occur?
When excitation significantly exceeds inhibition
MoA of phenobarbital?
Enhances activity of GABA receptor
Depresses glutamate activity
Reduces Na/K conductance
MoA of phenytoin?
Blockage of Na Channels and inhibitory action on Ca and Cl conductance
MoA of carbamazepine?
Blockage of neuronal Na channel conductance
MoA of Valproate?
affects GABA glutamatergic activity and reduce threshold of Ca and K conductance
MoA of Ethosuximide?
Inhibits Ca T-channel conductance
MoA of Lamotrigine?
Blockage of voltage-dependent Na conductance
MoA of oxcarbazepine?
Na Channel blockage
MoA of Topiramate?
Blockage of Na channels
Enhancement of GABA medicated chloride influx
MoA of Zonisamide?
Blockage of Na, K, and Ca channels
Inhibits glutamate excitation
MoA of Gabapentin?
Modulation of N-Type Ca channel
What are effective for partial and tonic-clonic seizures?
Valproate, phenytoin, carbamazepine, and phenobarbital
What are effective for absence seizures?
Ethosuximide
Valproate
What are effective only for partial seizures?
Gabapentin
Oxcarbazepine
What are effective for both partial and generalized seizures?
Lamotrigine
Topiramate
Levetiracetam
Zonisamide
SEs of carbamazepine?
Aplastic anemia
Hepatotoxicity
Stevens Johnson syndrome
Lupus-like syndrome
SEs of ethosuximade?
Bone marrow depression
Hepatotoxicity
SEs of Lamotrigine?
SJS
Toxic epidermal necrolysis
SEs of Phenytoin?
Aplastic anemia
Hepatic failure
SJS
Lupus
SEs of Oxcarbazepine?
Hyponatremia
Rash
SEs of Topiratmate?
Renal Calculi
Hypohidrosis
SEs of Zonisamide?
Renal calculi
Hypohidrosis
SEs of Phenobarbital?
Hepatotoxicity
Connective tissue disorder
SJS
SEs of Valproate?
Hepatotoxicity Hyperammonemia Leukopenia Thromocytopenia Pancreatitis
Hepatic cytochrome P450 inducers?
Caramazepine Phenobarbital Phenytoin Oxcarbazepine Topiramate
Older AEDs are which category of drugs? Newer AEDS?
D
C
Disabling seizures?
Causing impaird quality of life, limited educational or occupational opportunities, physical injuries, or social compromise
Generalized convulsive status epilepticus?
Continuous, generalized convulsive seizure lasting more than 5 minutes or two or more sequential seizures occurring without full recovery of consciousness
