SA Med - Neuro - Seizures

drraythe's version from 2017-10-02 05:20


Question Answer
What is a seizure?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 cz for recurrent seizures
What is PRIMARY epilepsy?Idiopathic epilepsy
What is SECONDARY (symptomatic) epilepsy?Intracranial czs (actual brain prob)
What is REACTIVE epilepsy?Extracranial czs - Not truly considered to be epilepsy.
What can be some metabolic czs of reactive epilepsy? Where will the seizures be brain-location wise(Extracranial czs of epilepsy, not considered true epilepsy- something extracranial is making the brain go nuts)
Hepatic encephalopathy
Electrolyte abnormalities
It will be Bilaterally symmetric (global)
What can be some toxic czs of reactive epilepsy? Before you see the epilepsy, what might you see first?Might see GI signs first - can really be almost any toxin
Metronidazole are common
Idiopathic Epilepsy - WHO gets this, & 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 yrs
Is Idiopathic Epilepsy generalized or partial?Usually generalized but may be partial
When does idiopathic epilepsy occur in PTxs? 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 w/ thatThere will be a Prodrome/aura which is a change in sensorium or behavior. This is happening bc of Initial focal signs that precede generalization
What is the postictal period, & what does it present like?Recovery period after the seizure. Confusion, blindness, ataxia, somnolence, polyphagia
What is the interictal period?Time btwn seizures
What would make a seizure an isolated seizure?1 seizure in a 24 hour time period
Which are ER: isolated seizure, cluster seizure, status epilepticusCluster & status are both ER
What are cluster seizures? (Definition of their frequency basically)Greater than 1 seizure in a 24 hour time period, but w/ normal interictal periods
What is status epilepticus?(Frequency) Seizure that lasts for > 5 minutes, Or a series of seizures w/ 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 Dz but can be can be idiopathic
What is a SIMPLE partial seizure?Contralateral **motor disturbance w/ no change in sensorium
What is a Complex partial seizure?Sensory/behavior disturbance. AKA psychomotor seizures
What should you know about the progression of a partial seizure?They can GENERALIZE!!!
What is the most common type of seizure in an animal?Generalized Seizures
What is a Generalized Seizure?Reflects dysfunction in both hemispheres
How will a generalized seizure present?Will see a loss of consciousness. Can observe urination, defecation, ptyalism. Can see apnea & hyperthermia.
What are the 6 Types of Generalized Seizures?(1) Tonic-clonic seizures (grand mal)
(2) Tonic seizures (stiff)
(3) Clonic seizures (paddling)
(4) Atonic seizures (limp)
(5) Myoclonic seizures
(6) Absence seizures (petit mal) ("zone out" for a sec in humans)
What does tonic mean what does clonic meanTonic = stiff
Clonic = paddling.
What is the fancy term for a seizure czd by too much excitation & what are the 2 excitatory NTs regarding this?EPSP: Excitatory postsynaptic potential. Aspartate & glutamate are the NTs
What is the fancy term for a seizure czd by not enough inhibition & what are the 2 inhibitory NTs regarding this?IPSP: inhibitory postsynaptic potential. GABA & Glycine are the NTs
What can cz a change in the threshold for seizures?Changes in the neuronal environment.
List of things which can look like seizures but are notSyncope
Normal or abnormal REM sleep bh
Bh disorders
Vestibular syndrome
Cervical pain
Head tremors
Other collapse
When should you perform your neuro exam?Interictal period
Exs of structural brain probs/Dzs which can lead to seizuresTumor
Trauma malformation
What is CT good for? VS what is MRI good for?CT is good for decent imaging of the forebrain
Especially for large
Focal lesions
HOWEVER, MRI is the superior brain imaging
What will CSF look like w/ encephalitis, meningitis?Pleocytosis, High protein
Which 2 fungi can cz seizures which you can Dx w/ some CSF possibly?Cryptococcus/blastomycosis (Blasto= broad budding base. Cyrpto= india ink, halo around them)
What 2 tumors might cz seizures which you can Dx from CSF?Lymphoma, Histiocytic sarcoma
Spinal tap risks (1) contraindications (1)(1) RISK: Pithing (stabbing brain stem)
(2) CI: Intracranial hypertension → Brain herniation secondary to acute pressure gradient change
What is Electroencephalography? What does it tell you in terms of seizures?Recording of spontaneous electrical brain activity. Provides no structural information & cannot localize Dz, but it Can be useful to determine whether or not seizures are occurring


Question Answer
What are the 4 drugs which are MAINTENANCE anticonvulsants?Phenobarbital
Bromide salts
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?Phenobarbital
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 w/in 2-3wk)
ADVERSE: Hepatotoxicity* which can be possibly fatal, Blood dyscrasias, Skin eruption
What is the major adverse Rxn to phenobarb that you should look out for?Hepatotoxicity - possibly fatal
What are 2 lab abnormalities that being on maintenance phenobarb will cz?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 w/ a phenobarbital maintenance plan?First, at steady state (~2 weeks), routinely, every 6 mos (w/ 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 2 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 w/ pancreatitis, megaesophagus, Cats: fatal pneumonitis (Idiosyncratic, allergic Rxn)
Which drug czs a fatal pneumonitis in cats so only should be given to dogs?Bromides (NaBr KBr)
How does maintenance bromide affect the chem panel?Cl- artificially elevated. Avoid diet changes-- chloride content (salt)
CI for bromides in cats? Dogs?CI in cats: you are a cat. Bc idiosyncratic fatal pneumonitis
DOGS: Eliminated through kidneys, so avoid in renal compromise.
In what situations would you do therapeutic drug monitoring for bromides?After 1 elimination half life (1 mo) (Gives you a ballpark & can adjust dose early if needed), At steady state (3 mos), Routinely, every 6 mos (w/ 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 & cats? SEs?Ok for both, also SEs are few & far btwn-- BUT EXPENSIVE :(
When would you therapeutic drug monitor w/ levetiracetam?Lol dont need to, very safe drug
MOA for Zonisamide?Largely unknown, but Blocks Na + & Ca ++ channels, & then Binds GABA’s Cl - channel, hyperpolarizing
SEs of zonisamide? When should you therapeutic drug monitor?Few & far btwn! Sporadic case reports of renal tubular acidosis. TDM is not required
If there are refractory seizures on drug therapy, what should you think about & 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 w/in therapeutic range. Lastly, consider Organic brain Dz & Discuss referral to a neurologist for a full seizure work-up (Tx of underlying Dz)

ER seizure stuff

Question Answer
What are the 2 ER seizure situations again?Cluster seizures (>1 seizure/24hr w/normal interictal periods) & 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 ANx
& 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 PTx (admin O2 if needed)
(a) Establish a patent airway
(b) Quick assessment tests (Establish euglycemia &/or euvolemia)
(c) Treat hyperthermia if present
If you have your Sz PTx 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 PTx, what should you do, & 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 PTx for respiratory depression!! Then, Begin maintenance therapy the following day. ( Draw blood for drug level after the loading is complete )
If the PTx 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 & doesn’t really like to mix w/ other things
What are some last-ditch efforts (drugs) to control seizures? Why are they considered last ditch?Propofol CRI, Pentobarbital CRI, gas ANx. Last ditch bc These all cz (cardio) respiratory depression, requiring extremely close monitoring &/or intubation (ventilator).
What are some supportive therapies you can provide for them?Express/manage urinary bladder q6-8 hr
Keep PTx clean & dry of urine/feces
Well-padded bedding & frequent rotation
Intravenous fluids & nutrition assistance
Close monitoring of hemodynamic parameters, oxygenation
Ventilation, etc.
What is considered good at home seizure control?Good seizure control: no more than 1 seizure per 4-6 weeks
What at-home seizure control drug can you give for cluster seizures?Oral clorazepate
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 anti-seizure drugs?NOT cold turkey
What does Tx do to seizure amt/frequency?Seizures (unless reactive) likely will not disappear w/ Tx. Goal= reduce seizure frequency & severity