Seizures Flashcards by Payton Bayless

What are the seizure criteria and how many must the episode match to be considered a seizure?

Hypersalivation, urination and/or defecation - PS signs
Tonic/tonic-clonic movements or rhythmic contractions of facial or appendicular muscles
Altered mentation or decr responsiveness
Postictal period - abnormal behavior or mental state noted; blind, frantic, ataxia, dullness

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What are things that could causes a seizure-like episode?

Narcolepsy/cataplexy, REM sleep movement disorders
Syncope
cardiac dz
hypoglycemia
myoclonus
anemia
e- abnormalities
Atlanto-axial luxation
COMS
vestibular events
head bobbing

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Define a seizure. What are some possible causes of a a seizure?

Hypersynchronous electrical activity causing abnormal and excessive discharge of neurons in the brain

Decr inhibition (GABA, glycine)
incr excitation (glutamate, aspartate)
high estrogen levels/low progesterone

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Why is spaying an epileptic patient often indicated?

Because estrogen decreases seizure threshold and progesterone enhances GABA and inhibits glutamate

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What are the phases of seizures?

Pre-ictal: may be a partial seizure

Ictal: seizure

Post-ictal: confused, absent menace

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What is the difference between cluster seizures and status epillepticus?

Cluster - more than 1 seizure in 24 hours

Status epillepticus - longer than 5-20 min or not normal b/t events

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What is epilepsy and what are the 4 etiologies?

Epilepsy = more than 1 seizure

Etiologies:

Familial/idiopathic/primary: presumed genetic 1-4 yrs
Symptomatic/Secondary - known underlying cause (neoplasia, infection, inflammation)
Reactive
Cryptogenic - suspect cause though not identified

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What is a generalized seizure?

Focus in one cortex that reaches thalamus and disseminated throughout the brain

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What is the difference between a simple and complex focal seizure?

Simple - consciousness unimpaired

Complex - consciousness impaired: fear, anger, behavioral abnormality, autonomic, “psychomotor”

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What is a simple partial seizure?

Disturbance of motor function only, no loss of responsiveness

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What is a complex partial seizure?

Disruption of the sensorium +/- motor (fly biting/flank chewing), decreased responsiveness

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What are your initial diagnostics for a seizure work-up?

Hx, exam findings, MDB, rads, abd U/S, fundic exam, endocrine status, hepatic function, current anti-convulsants levels

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What are three advanced diagnostics you can use for a seizure workup?

Advanced imaging - CT vs. MRI (gold standard)

Electroencephalogram (EEG)

CSF analysis - infectious dz titers

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What are diseases that could cause seizures that follow the DAMNITV scheme?

Congenital - hydrocephalus

Metabolic

Neoplasia - primary vs. metastatic

Infectious/Inflammatory - viral, protozoal, fungal, MUE, GME, NME

Vascular event - stroke vs. hemorrhage

Epilepsy - familial vs. cryptogenic

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What are metabolic causes for seizures?

Hypo- or hyperglycemia
DM, insulinoma
Electrolyte disturbances (Na, Ca, Mg)
Renal failure
Hepatic dz/failure - PSS
Toxins

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What types of neoplasia can cause seizures?

Primary - meningioma, glioma, lymphoma, insulinoma

Secondary Metastatic - lymphoma, hemangiosarc

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What are inflammatory/infectious causes of seizures?

Autoimmune, MUE, GME, NME, infectious: tick borne dz, protozoal (Toxo, Neospora), fungal (crypto, blasts, aspergillus), viral (rabies, distemper)

What are some vascular events that can cause seizures?

Ischemic/stroke, hemorrhagic, underlying endocrine disorders, underlying infectious dz

What are the causes of seizures in cats?

Epilepsy
thiamine deficiency
infectious (cuterebra, crypto, FIP, FIV, Toxo)
Hypertensive encephalopathy (CRF, hyperthyroid)
Meningioma, LSA
PSS in kittens
Vascular

What are important factors that play a role in quality of life when managing epilepsy?

Underlying cause, seizure freq and severity, owner compliance, stress associated w/ seizure event, stigma assoc w/ certain AEDs

What are goals of therapy for management of epilepsy?

Decr frequency, decr severity, and good quality of life

What are AEDs that block Na channels?

Phenytoin, Valproate, Topiramate

What are AEDs that block Ca channels?

Topiramate, Gabapentin/Pregabalin

What AEDs enhance GABA?

Benzos, barbiturates

What AED inhibits glutamate?

Topiramate

What are the most common anticonvulsants?

Phenobarbital, KBr, Levetiracetam (Keppra), Zonisamide, Pregabalin (Lyrica)

Describe phenobarbital

**MOA**: incr neuronal responsiveness to GABA, anti-glutamate, decr Ca flow into neurons **Half-life:** 40-90 hours Ideal b/w **25-35 mcg/ml** and monitor q 6mo

What are some side effects of phenobarb?

PU/PD/PP hepatotoxicity (esp. when blood \>35mcg/ml) auto-inducer of cP450 sedation/ataxia

Describe KBr

**MOA**: traverse neuronal Cl channel and hyperpolarize neuronal membrane to cause an incr seizure threshold Half-life: 28d, steady state @ 4 mo Excreted via kidneys

What are some side effects of KBr?

Coughing (pneumonitis in cats) - **DO NOT USE IN CATS** Pancreatitis - may develop elevated triglycerides vomiting

Describe Levetiracetam

**MOA**: inhibit voltage-gated Ca channel, neuro protective Half-life: 3 hours Given PO TID to QID

What are the side effects of Levetiracetam?

Few to no side effects - transient sedation

Describe Zonisamide

**MOA**: block T-type Ca and voltage gated Na channels, bind to Cl channels associated with GABA Half-life: 15 hours in dogs

What are the side effects of Zonisamide?

Ataxia, lethargy, KCS, vomiting, polyarthropathy, suppression of thyroid hormone synthesis, hepatotoxicity, renal tubular acidosis, calcium oxalate urolithiasis

Describe Gabapentin

**MOA**: structural analog to GABA and enhances action, inhibit voltage gated Na/Ca channels Half-life: 3- 4hrs \***Terrible anticonvulsant, great for pain**

Describe pregabalin (lyrica)

**MOA:** Gabapentin analog - decr Ca influx resulting in decr glutamate and substance P Half-life: 7hrs Expensive human product don’t routinely monitor drug levels

What are principles for monitoring AED use in epileptic patients?

* Use a single agent to its maximal effect before adding or switching to another AED * monitor levels for phenobarb, KBr, and Zonisamide * monitor side effects

What are some alternative treatments for epilepsy?

Vagal nerve stimulators - internal and external Ketogenic diet - not easy in dogs Food allergies - novel protein or reduced antigen food?

What are the effects of status epilepticus?

Results in neuronal cell death from excitotoxicity from glutamate and influx of Ca through NMDA glutamate receptors

What are the goals of emergency management therapy for seizures?

* Stop seizures! * support systemic function * protect brain function * assess underlying cause

What are your emergency management medications options for seizures?

Bolus diazepam (IV or per rectum) midazolam (IV or intranasal) AED loading dose (Phenobarb, KBr) CRIs of prop, midazolam, dexmed, Levetiracetam

Which disease is which?