Seizure Disorder

Question 1

What is Syncope? causes?

Answer 1

• Sudden loss of consciousness
• Deprivation of oxygen or glucose
  
  • Cardiopulmonary disease
  • obstructive vascular disease
  • lose blood pressure
  • metabolic
• Complete recovery in seconds to minutes

Question 2

What are the signs of syncope?

Answer 2

• Muscle weakness ⇢ Ataxia ⇢ Collapse
• Initially motionless, flaccid
• Progress to stiffness, jerking
• Urination, defecation
• Very brief confusion upon recovery

Question 3

What is a seizure?

Answer 3

• Any event that is brief, recurrent, episodic, unpredictable and unexplained should be considered a possible seizure event
• Abnormal hypersynchronous electrical activity of neuronal networks
• Alteration in behavior, consciousness, motor activity, sensation, autonomic function
• Seizure focus

Question 4

What are the types of seizures?

Answer 4

• Generalized
  
  • most commonly tonic-clonic (stiffness - movement)
  • Consciousness is lost
  • Loss of autonomic control
  • Can include absence seizures, myoclonic
• Partial
  
  • one hemisphere or lobe
  • confusion as to presence in dogs/cats
  • Consciousness may be retained, herking motion of muscle/muscle groups
  • Fly biting
• Other Types:
  
  • mild generalized
  • Focal motor (paroxysmal dyskinesia differential)
  • Psychomotor
  • Visceral

Question 5

Summarize episodic neurologic symptoms and their causes

Answer 5

• Focal neurologic dysfunction
  
  • transient ischemic events
  • partial seizures
• Alterations of consciousness
  
  • seizures, syncope
  • Narcolepsy
  • portosystemic shunt
• Dizziness
  
  • Peripheral vestibular
  • Hypertension
• Misc:
  
  • pheochromocytoma
  • Arrhythmias
  • Hypoglycemia
  • Cataplexy
  • Exercise-induced collapse
  • Paroxysmal dyskinesia

Question 6

What is Paroxysmal Dyskinesia?

Answer 6

• Hyperkinetic movement disorder
• “Cramping syndrome”
• Episodes of disturbed movement
  
  • self-limiting, non-painful
  • Absence of autonomic signs
  • Consciousness, not impaired
  • Can last seconds, minutes, hours
  • Beginning and end are abrupt
  • Normal in between episodes
• Various presentations
  
  • Staggering without falling
  • Unable to stand but crawl deliberately
  • Uncontrollable trembling
  • Increased muscle tone; head tremor
• Causes:
  
  • Gluten-responsive; fluoxetine; acetazolamide; anti-epileptics (zonisamide); scientific neglect

Question 7

What are the phases of a seizure

Answer 7

• Aura, Pre0ictal period
• Ictus - seizure itself
• Post-ictus - variable duration, temp blindess
• Interictal period

Question 8

What are teh classifications of seizure etiology?

Answer 8

• Primary Epileptic
  
  • no underlying cause
  • familial epilepsy
• Secondary Epileptic
  
  • identifiable structural cerebral lesion
  • Hydrocephalus, neoplasia
• Reactive epileptic
  
  • normal brain, metabolic cause

Question 9

How can the type of seizure (etiology) be differentiated?

Answer 9

• Signalment
  
  • Juvenile, old dogs, cats = secondary or reactive
  • Breeds with high prevalence of familial
• Normalcy between seizures
  
  • abnormal interictal period = secondary
    
    • Can still have a normal period
• Time between 1st and 2nd seizure
  
  • Short = secondary or reactive
  • >4wks = Primary
• Physical & Neurological exam
  
  • Dome-shaped head: hydrocephalus (SES)
  • Copper-colored eyes in cats: PSS (RES)
  • Asymmetric, localizing signs interictal (SES)
• Abnormalities on CBC, Chemistry = Reactive

Question 10

What are primary epileptic seizure?

Answer 10

• No underlying pathology
• Familial in many breeds
• Epileptic neurons
  
  • excessive discharges from spontaneous depolarization
  • Synchronous discharge of a population required for seizure
  • Paroxysmal Depolarizing Shift
• Epileptiform activity spread by cerebral connections
  
  • Transverse, projection, and association fibers
• Secondary epileptogenic focus development
  
  • dependent, intermediate, and independent phases

Question 11

What are Secondary Epileptic Seizures?

Answer 11

• Intracranial disease affecting the cerebrum
• Juvenile dogs:
  
  • congenital or developmental (hydrocephalus)
  • Hereditary (lysosomal storage disease)
  • Infectious (canine distemper)
• Old dogs: neoplasia
• Cats: FIP, Feline ischemic encephalopathy, FIV/FeLV, Cuterebra, prior trauma

Question 12

What are Reactive Epileptic Seizures

Answer 12

• Extracranial disease affecting the cerebrum
  
  • hypoglycemia (toy breeds, puppies, hunting dogs, old dogs with insulinoma)
  • Hypocalcemia (other electrolyte abnormalities)
  • Hypertension (CKD, essential, hyperviscosisty syndrome)
  • Portosystemic shunts (cats)
  • Encephalopathy (thiamine deficiency, hypothyroid or hyperthyroid
  • Toxicities (lead)
  • Renal failure

Question 13

How do you determine when to treat seizures?

Answer 13

• No:
  
  • Very infrequent seizures (2-3 / year)
  • Infrequent with no change (1/month or less)
    
    • Repetitive seizures may lead to kindling and mirroring
• Yes:
  
  • Frequent seizures
  • decreasing interictal period
  • cluster seizures

Question 14

What are the treatment options for epileptic seizures?

Answer 14

• Facilitate GABA
  
  • Phenobarb
  • KBr
  • Benzos
• Inhibit glutamate
  
  • Zonisamide
  • Levetiracetam
  • Gabapentin
  • Felbamate
  • Topiramate

Question 15

Why is potassium bromide contradicted in cats?

Answer 15

pulmonary toxicity

Question 16

What are Cluster Seizures

Answer 16

• Multiple seizures within 24-hour period
• At home management
  
  • per rectum or intranasal diazepam
  • Gabapentin
  • Additional doses of phenobarb
• Goal is to reduce severity and duration of cluster

Question 17

What is Status Epilepticus?

Answer 17

• Failure of normal termination
  
  • seizure >5 min
  • >3 seizures w/out return of consciousness
• Results in Brain Damage
  
  • Hypoxia, hyperthermia, acidosis
  • Loss of autoregulation
• Must terminate ALL seizure activity
  
  • Diazepam or Midazolam (bolus, CRI)
  • IV levetiracetam
  • Propofol CRI
  • Isoflurane anesthesia
  • Initiate phenobarb therapy