Imbalanced neuronal activity where excitation>inhibition. This leads to Uncontrolled, synchronous neuronal discharge
what is epilepsy? idiopathic epilepsy?
This is RECURRENT seizures. Idiopathic epilepsy is when there is Unknown cause for recurrent seizures
what is PRIMARY epilepsy?
what is SECONDARY (symptomatic) epilepsy?
Intracranial causes (actual brain prob)
what is REACTIVE epilepsy?
Extracranial causes- Not truly considered to be epilepsy.
what can be some metabolic causes of reactive epilepsy? where will the seizures be brain-location wise
(extracranial causes of epilepsy, not considered true epilepsy- something extracranial is making the brain go nuts) Hepatic encephalopathy, hypoglycemia, electrolyte abnormalities. It will be Bilaterally symmetric (global)
what can be some toxic causes of reactive epilepsy? before you see the epilepsy, what might you see firsT?
Might see GI signs first- can really be almost any toxin, but Lead, strychnine, organophosphates, ivermectin, metronidazole are common
Idiopathic Epilepsy-- WHO gets this, and HOW? AGE?
Inherited or familial problem which you see in (Beagle, Labrador retriever, Dachshund, golden retriever, Collie, English Springer spaniel, Belgian tervuren, keeshond, British Alsatian <--lol not even trying to memorize this) Can occur in any breed! RARE in the cat. Age of onset 1-5 years
is Idiopathic Epilepsy generalized or partial?
Usually generalized but may be partial
When does idiopathic epilepsy occur in patients? how frequent are the seizures?
When theyre sleeping o_O. Seizures are Relatively infrequent- May increase in frequency if not treated. Rarely cluster or status epilepticus.
what will (interictal) neuro exam be like in idiopathic epilepsy sufferers?
Normal neurologic examination (interictal)
What is ictus?
The seizure itself
what is something that occurs in the preictal period, explain what is going on with that
There will be a Prodrome/aura which is a Change in sensorium or behavior. This is happening because of Initial focal signs that precede generalization
what is the postictal period, and what does it present like?
Recovery period after the seizure. Confusion, blindness, ataxia, somnolence, polyphagia
what is the interictal period?
time between seizures
what would make a seizure a Isolated seizure?
One seizure in a 24 hour time period
Which are ER: isolated seizure, cluster seizure, status epilepticus
cluster and status are both ER
what are cluster seizures? (definition of their frequency basically)
greater than one seizure in a 24 hour time period, but with normal interictal periods
what is status epilepticus?
(frequency) Seizure that lasts for > 5 minutes, Or, a series of seizures with abnormal interictal periods
Partial Seizures: what are these? Why do they happen?
Nature of the seizure depends on its location (it isnt the whole brain). Typically reflect structural brain disease but can be Can be idiopathic
what is a SIMPLE partial seizure?
Contralateral **motor disturbance with no change in sensorium
what is the MOA for Phenobarbital (in terms of stopping seizures also)
Antiglutamate effects (glutamate=excitatory), also Increased neuronal reactivity to GABA(more inhibitory), Decreased Ca ++ influx into neurons
what is the cheaper, first line drug for maintenance tx of seizure?
what are the EXPECTED side effects of phenobarbital? what about the ADVERSE SEs?
EXPECTED: Polyuria, polydipsia, polyphagia, Sedation, ataxia, possibly restlessness (These signs usually abate within 2-3wk). ADVERSE: Hepatotoxicity* which can be possibly fatal, Blood dyscrasias, Skin eruption
what is the major adverse reaction to phenobarb that you should look out for?
hepatotoxicity- possibly fatal
what are two lab abnormalities that being on maintenance phenobarb will cause?
ALP elevation, Apparent hypothyroidism (cant do accurate thyroid testing once theyre on this)
when are the times/situations where you would want to do therapeutic drug monitoring with a phenobarbital maintenance plan?
First, at steady state (~2 weeks), Routinely, every 6 months (with routine blood work), After a dose change, If side effects arise.
What are the things you should be aware of if the dog is on maintenance phenobarb?
Beware MANY drug-drug interactions, Do not draw in a serum separator tube (Therapeutic level: 15-40 μg/ml, 25-30 in reality <--idk if these things are worth memorizing)
what are the two types of bromides you can use as maintenance therapy? How do you give them differently?
Potassium bromide (oral), sodium bromide (IV) ((obv no K+ IV lol)
MOA of the bromides?
Hyperpolarizes neurons (in class she said acts like Cl-, so inhibitory neuronal enviro. Hypo-polarize= lower threshold. hyperpolarize= bigger difference=inc threshold)
WHO do you give the bromides to? (how much?)
***Only for use in dogs**** (im not bothering to memorize doses) 20-40 mg/kg/day....Use slightly higher dose if NaBr (bc not overloading potassium, lol), Can be given once daily. Divide to avoid osmotic GI effects
what are the EXPECTED side effects of the NaBr/KBr? What are the ADVERSE side effects?
EXPECTED: Polyuria, polydipsia, polyphagia, Sedation, ataxia or stiffness, possibly restlessness. (abate w/in 2-3wk). ADVERSE: Pruritic skin eruption, Association with pancreatitis, megaesophagus, Cats: fatal pneumonitis (Idiosyncratic, allergic reaction)
which drug causes a fatal pneumonitis in cats so only should be given to dogs?
bromides (NaBr KBr)
how does maintenance bromide affect the chem panel?
CI in cats: you are a cat. Because idiosyncratic fatal pneumonitis. DOGS: Eliminated through kidneys, so avoid in renal compromise.
in what situations would you do therapeutic drug monitoring for bromides?
After one elimination half life (1 mo) (Gives you a ballpark and can adjust dose early if needed), At steady state (3 months), Routinely, every 6 months (with routine blood work), After a dose change, if SEs arise. (Theraputic doses: 1-3 mg/ml if monotherapy. 1-2 mg/ml if also on phenobarbital )
MOA of Levetiracetam?
Binds the synaptic vesicle protein SV2A --> Prevents excitatory neurotransmitter release. Also, Neuroprotective, prevents kindling
is levetiracetam safe for both dogs and cats? SEs?
ok for both, also SEs are few and far between-- BUT EXPENSIVE :(
When would you therapeutic drug monitor with levetiracetam?
...lol dont need to, very safe drug
MOA for Zonisamide?
Largely unknown, but Blocks Na + and Ca ++ channels, and then Binds GABA’s Cl - channel, hyperpolarizing
SEs of zonisamide? When should you therapeutic drug monitor?
Few and far between! Sporadic case reports of renal tubular acidosis. TDM is not required
If there are refractory seizures on drug therapy, what should you think about and do?
Is the pt getting the rug? question the owners. Then do Therapeutic drug monitoring-- Dosing adjustment or owner counseling may be needed. Can also do add-on drug therapy If drug levels are within therapeutic range. Lastly, consider Organic brain disease and Discuss referral to a neurologist for a full seizure work-up (Treatment of underlying disease ).
cluster seizures (>1 seizure/24hr w/normal interictal periods) and status epilepticus (seizure >5min or series of seizures w/abnormal interictal period)
what are the 7 drugs you can give as ER tx?
*Diazepam/midazolam! Also propofol, pentobarbital (lol wut), Gas anesthesia, and then 3 of the 4 maintenance drugs: phenobarb, KBr, Levetiracetam (not zonisamide or NaBr)
what should your initial tx of ER seizure pt be?
(1) Stop the seizure: Establish intravenous access if possible, Diazepam/midazolam: 0.5 mg/kg or to effect (Can be given rectally 1-2 mg/kg also). (2) Treat the rest of the patient (admin O2 if needed) (a) Establish a patent airway (b) Quick assessment tests (Establish euglycemia and/or euvolemia) (c) Treat hyperthermia if present
If you have your sz pt arrive, you give ER drug, they stop, but then they have another seizure... what do now?
0.5 mg/kg IV bolus diazepam/midazolam or to effect. Can try this up to 3 times
To prevent further seizures in the ER pt, what should you do, and when do you start maintenance?
Give Phenobarbital in a 24 hour load (in increments every 6 hours), typically IV but can be given orally. Monitor the patient for respiratory depression!! Then, Begin maintenance therapy the following day. ( Draw blood for drug level after the loading is complete )
If the pt continues to seizure no matter what, THEN what do you do?
Diazepam/midazolam constant rate infusion (CRI). OR Levetiracetam 60 mg/kg IV slow bolus
what should you know about using diazepam/midazolam in a CRI when they continue to seizure? (precautions about how to admin)
Both are light-sensitive, Diazepam adsorbs to plastic and doesn’t really like to mix with other things
What are some last-ditch efforts (drugs) to control seizures? Why are they considered last ditch?
Propofol CRI, Pentobarbital CRI, gas anesthesia. Last ditch bc These all cause (cardio)respiratory depression, requiring extremely close monitoring and/or intubation (ventilator).
what are some supportive therapies you can provide for them?
Express/manage urinary bladder q6-8 hr, Keep patient clean and dry of urine/feces, Well-padded bedding and frequent rotation, Intravenous fluids and nutrition assistance, Close monitoring of hemodynamic parameters, oxygenation, ventilation, etc.
what is considered good at home seizure control?
Good seizure control: no more than one seizure per 4-6 weeks
what at-home seizure control drug can you give for cluster seizures?
what at-home seizure control drug can you give for status epilepticus?
Rectal diazepam 1-2 mg/kg using a red rubber catheter (valium adsorbs to plastic so can't send home in a syringe. lots of client education. ), or Bring to a local emergency clinic
how should you stop your antiseizure drugs?
NOT cold turkey
what does tx do to seizure amount/frequency?
Seizures (unless reactive) likely will not disappear with treatment. Goal= reduce seizure frequency and severity