Lecture 25

Question 1

What are the degenerative causes of seizures?

Answer 1

-hippocampal necrosis
-storage diseases
-some inherited diseases

Question 2

What are the characteristics of structural epilepsy?

Answer 2

-exam often abnormal with asymmetric deficits
-normal exam does not rule out structural disease
-type of seizure does not predict cause

Question 3

What are the characteristics of reactive epilepsy?

Answer 3

-majority of cases caused by intoxications and hypoglycemia
-just under half of all cases present in status epilepticus
-variable timing of presentation
-diffuse, bilateral, often symmetrical forebrain involvement

Question 4

Which conditions can appear like seizures?

Answer 4

-syncope
-vestibular dz
-feline hyperesthesia syndrome
-movement disorders/dyskinesia
-narcolepsy/cataplexy
-neck pain

Question 5

What are the goals of seizure treatment?

Answer 5

-decrease epileptic events
-decrease seizure severity
-avoid adverse effects
-decrease morbidity and mortality

Question 6

What should NEVER be the goal of seizure management?

Answer 6

patient never having another seizure (unrealistic goal)

Question 7

What are the findings in humans regarding the start of epilepsy treatment?

Answer 7

-no benefit to starting after a single unprovoked event due to potential side effects from seizure control medications
-the earlier treatment is started, the better potential for seizure control

Question 8

When should anti-epileptic drug treatment be started?

Answer 8

-structural lesion present
-status epilepticus or clusters
-2 or more seizures in a 6 month period
-severe postictal period

Question 9

Which anti-epileptic drugs are used in vet med?

Answer 9

-phenobarbital
-potassium bromide
-levetiracetam
-zonisamide
-diazepam/midazolam

Question 10

What are the characteristics of phenobarbital?

Answer 10

-dosed every 12 hours
-can load the drug over the course of 24 hours
-time to steady state is around 2 weeks
-metabolized by liver
-auto-inducer of p450 system
-leads to elevated ALP
-causes low T4/high TSH

Question 11

What are the dose-dependent side effects of phenobarbital?

Answer 11

-PU/PD/PP
-hyperexcitability
-restlessness
-sedation
-ataxia
-hepatotoxicity

Question 12

What are the idiosyncratic/non-dose-dependent side effects of phenobarbital?

Answer 12

-blood dyscrasias
-idiosyncratic hepatotoxicity
-superficial necrolytic dermatitis
-pancreatitis
-pruritis
-thrombocytopenia/leukopenia (cats)

Question 13

What are the characteristics of potassium bromide?

Answer 13

-dosed every 24 hours
-can load the drug over 5 days; faster will induce vomiting
-time to steady state is 3 months
-excreted in urine
-increased NaCl increases bromide excretion
-caution with renal insufficiency
-will cause elevated Cl on bloodwork

Question 14

What are the dose-dependent side effects of potassium bromide?

Answer 14

-PU/PD/PP
-sedation
-ataxia
-hyperactivity
-vomiting
-bromism

Question 15

What are the idiosyncratic side effects of potassium bromide?

Answer 15

-allergic pneumonitis
-pancreatitis
-adverse skin reactions

Question 16

Why is potassium bromide NEVER used in cats?

Answer 16

causes fatal pneumonitis

Question 17

What are the characteristics of levetiracetam?

Answer 17

-normal form is dosed every 8 hours
-extended release form is dosed every 12 hours
-can load drug with a double dose given one time
-time to steady state is 1 to 3 days
-excreted unchanged in urine
-hydrolyzed in the serum
-can excrete the capsule whole

Question 18

What are the side effects of levetiracetam?

Answer 18

-sedation
-ataxia
-restlessness
-vomiting
-decreased appetite

Question 19

What are the characteristics of zonisamide?

Answer 19

-dosed every 12 hours
-no ability to load drug
-time to steady state is 3 to 5 days
-only available for oral administration
-metabolized by liver
-increased clearance with concurrent phenobarb. use; must increase dose
-weak carbonic anhydrase inhibitor

Question 20

What are the side effects of zonisamide?

Answer 20

-sedation
-ataxia
-vomiting
-inappetence
-sulfonamide reactions
-KCS
-polyarthropathy
-acute hepatopathy
-renal tubular acidosis

Question 21

What are the characteristics of benzodiazepines?

Answer 21

-only for emergency situations
-metabolized primarily by liver
-short half life
-oral diazepam can cause fatal hepatic necrosis in cats
-midazolam is more potent than diazepam

Question 22

What are the characteristics of add-on treatment for seizure control?

Answer 22

-maximize the dose of one drug first before adding another
-do not stop initial drug when adding on

Question 22

Which seizure medications have the best success rates in patients?

Answer 22

-phenobarbital
-bromide

Question 23

What should be considered about the second drug when doing add-on treatment?

Answer 23

-choose drug with different method of action
-minimize drug interactions
-avoid additive toxicity
-poly-pharmacy vs QOL

Question 24

What is the importance of therapeutic monitoring when controlling seizures?

Answer 24

-determine effective concentrations -determine cause of drug failure -prevent toxic effects -individualization of treatment

Question 25

Which seizure control medications can be measured to determine levels in a patient?

Answer 25

-phenobarbital -potassium bromide

Question 26

What should be considered when choosing a seizure drug for a patient?

Answer 26

-cause of seizures -route of admin. -side effects -co-morbidities: liver, kidneys, chronic panc., sulfa reactions -owner factors; dosage frequency, cost, etc.

Question 27

Which diagnostics can be done in general practice to try and identify the cause of seizures?

Answer 27

-CBC/chem/UA -T4 -FIV/FeLV test -BP -fundic exam -infectious titers -bile acids

Question 28

When should a seizure patient receive an MRI?

Answer 28

-unknown seizure cause despite other testing -< 6 months or > 6 years of age -interictal abnormalities -status or cluster seizures -previous idiopathic seizures with drug resistance