Seizures Flashcards
What is the difference between seizures and epilepsy?
Seizure is an isolated incident
Epilepsy – recurrent unprovoked seizures
What are common leading factors that contribute to a patient having epilepsy?
- altered connection / structure of neurons
- Decreased GABA synthesis / Receptors
- Excess glycine – activating GABA receptors
What is a partial seizure and what is key difference between partial and general seizure?
- Very Brief
- Consciousness NOT impaired
- No Post-ictal symptoms
- Clonic (repeatitive) movements of face, arm, or leg
- Can have changes in sensation or psychiatric symptoms
What is the difference between partial seizure and complex partial seizure?
Complex:
- consciousness impaired with manifestations of automatic functions without patient’s knowing input
- gestures, chewing, lip smacking, repeating speech
- patient unable to recall and has post-ictal state
What are the different location/etiology of complex partial seizures?
Temporal Lobe Origin -- Preceded by an Aura of some kind of indication -- Autonomic Symptoms -- Postictal Phase Frontal Lobe Origin -- Arrest of current activity -- Motor manifestations / blank stare -- Brief On/Off attacks
What is an Absence seizure?
- Abrupt Cessation of Activity
- Change in Facial expression – blank stare
- No Aura / Less than 30 seconds / No post-icle
- Clonic Eye Movements – blinking/nystagmus
- Autonomic Phenomena – dilation, sweating, pallor
- *Preservation of Actions/Speech** «- Actions?
What seizures are considered generalized seizures?
- Absence
- Tonic
- Atonic
- Clonic
Would full body clonus be considered a Clonic Seizure?
- NO.
Clonic Seizure is focal or multifocal, but NOT generalized.
– if the clonus migrates, indicates there is an abnormality
What is the difference between a Tonic Seizure and Atonic Seizure?
Tonic – brief, sudden onset of EXTENSOR tonicity with impaired consciousness
Atonic Seizures – Sudden loss of muscle tone with a brief loss of consciousness – very rare
What can be a precursor to Absence or Tonic seizures?
Myoclonic Seizures can be seen just prior to Absence or Tonic/Clonic seizures
– Sudden, very brief Shock-like, jerk-like motions
If a seizure is sustained for more than 30 minutes or repetitive seizures?
- Status Epilepticus
How would you need to evaluate a patient if they have new onset seizures?
Initial Work up
– General Lab Work – Glucose/Chem/CBC, etc
Second Line – after patient recovers
– LP, LFT, Toxo, EEG, MRI
What do Valproic Acid, Carbamazepine, Oxcarbazepine, and Phenytoin all have in common?
They all block sodium channels from rapid repetitive firing.
Phenytoin and Carbamazepine have similar mechanisms, but how are they different?
Phenytoin – changes from first-order to zero order as dose increases (within therapeutic range).
Carbamazepine - Unpredictable absorption, induces P450s, and can cause Spina Bifida
If there is generalized clonic activity that is very sudden and brief lasting, appearing as shocks of movement, what might be classified as?
Myoclonic Seizures
- Generalized shock-like actions
- Can be confined to the face
What kind of health maintenance is important for patients who are chronically on Phenytoin?
- Dental Check Ups
- - Checking/Looking for gingival hyperplasia
If a patient is currently undergoing status epilecticus?
Fosphenytoin – IV Phenytoin
What is a frequent consequence of taking Phenytoin and Carbamazepine?
CNS Toxicity – Ataxia, Diplopia, etc.
What drug with a similar mechanism to Phenytoin has less CNS side effects?
Oxcarbazepine
What is the first line therapy for Absence Seizures and why is it better than the other choices?
Ethosuximide
- long half-life, not protein bound, well-absorbed
What is the mechanism of action of Ethosuximide?
Reduces low-threshold calcium currents that flow in the thalamic neurons
When would Valproic Acid be indicated for use?
- A patient with Absence seizures, but also tonic-clonic seizures
- Not first line for Absence Seizures
- Can be used for most anything. Generalized Tonic-Clonic, Partial, and Myoclonic Seizures
If a patient is on Valproic Acid, what might need to be monitored?
- Hepatotoxicity
- If Female, make sure not pregnant. Spina Bifida
What are the mechanisms of action of Valproic Acid?
- Blocks repetitive firing of Na+ channels
- Reduces low-threshold Calcium currents
- Increases GABA concentrations
What drug acts antagonistically at the allosteric glycine site on the NMDA receptor?
Felbamate
- used when seizures are resistant to other drugs
- aplastic anemia and hepatic failure
What can be used as an adjunctive therapy to partial seizures?
Gabapentin
Pregabalin
What is unique about how NMDA channels are activated?
They require both NMDA and Glycine to activate the gated channel
What drug inhibits repetitive actions of Na+ channels and does NOT interfere with other drugs (doesn’t bind proteins or induce)
Lamotrigine
– FDA approved for bipolar, used well for seizures
What seizure drug can cause Stevens-Johnson syndrome?
- Lamotrigine
What drug blocks the spread of seizures by blocking glutamine receptor subtype, which is typically used as add-on therapy for partial seizures?
Topiramate
- weight loss
- prevents migraines
What drugs inhibits the reuptake of GABA in the clefts?
Tiagabine
- add on therapy for partial and complex seizures
What can be added for treatment for myoclonic and generalized tonic-clonic seizures?
- Levetiracetam - Keppra
What drug reduces the voltage-dependent transient inward currents of both sodium and calcium channels?
Zonisamide
- adjunctive therapy for ADULTS with partial seizures
What drug can cause permanent vision damage?
Vigabatrin
What agent can be used to irreversibly inhibit GABA metabolism, causing them to remain around longer?
Vigabatrin
What are the drugs that should be limited use in women of child bearing age?
- Valproic Acid
- Carbamazepine
