Lapis ISSN 2398-2969

Seizures

Synonym(s): Ictus, Convulsions, Fits

Contributor(s): Michelle Campbell-Ward, Lesa Longley, Lesa Thompson, Molly Varga, Sarah Pellett

Introduction

  • Seizures are an uncommon presentation in rabbits Decision tree: seizures.
  • Cause: a seizure, fit or convulsion is a manifestation of abnormal neuronal hyperactivity. Seizures may occur due to a primary intracranial lesion or secondary to aberrations elsewhere in the body. They are most often caused by infectious agents, toxins or metabolic disorders. 
  • Signs: the clinical appearance is variable, but typically paroxysmal uncontrolled tonic-clonic contractions of the voluntary muscles are observed.
  • Diagnosis: signs, history, physical and neurological examination, CBC, urinalysis, biochemistry, radiography, CT, MRI, CSF analysis, EEG.
  • Treatment: diazepam/midazolam to control seizures. Alfaxan or propofol should be used to anesthetize animal if diazepam/midazolam fail to control seizures.
  • Prognosis: variable to poor.
Print off the Owner factsheet on Seizures - convulsions/fitting to give to your client.

Presenting signs

  • Rabbits may present during a seizure.  
  • More commonly, the animal is examined after having had one or more seizures from which it has partially or wholly recovered. 
  • Seizures may be generalized (loss of consciousness with bilaterally, symmetrical motor signs involving the whole body) or, less frequently, partial (focal motor activity without loss of consciousness).
  • There may be no clinical signs apparent at the time of presentation. 
  • Seizures may occur in the terminal stages of disease, immediately prior to death. 
  • Owners often describe a seizure as sudden collapse or an episode of generalized weakness.
  • Accompanying presenting signs vary depending on the underlying cause.

Acute presentation

  • Seizures, by definition, are acute in onset. 
  • Status epilepticus: 
    • Describes rapidly recurring seizures with incomplete recovery between episodes.
    • Is a serious emergency that can result in transient brain hypoxia, permanent brain damage or death of the patient. 
    • May be associated with toxicities, metabolic abnormalities or progressive brain disease.

Breed predisposition

  • Idiopathic epilepsy has only been reported in Beveren White and Vienna White rabbits.

Public health considerations

  • A number of zoonotic diseases are associated with seizures in rabbits. 
  • The most common is Encephalitozoon cuniculi infection Encephalitozoon cuniculi, which can potentially pose a risk to immunocompromised people.
  • In areas where rabies is endemic, this serious zoonosis should remain a differential diagnosis until proven otherwise.

Cost considerations

  • Moderate to expensive.
  • If the cause of a seizure is readily identified and treatment uncomplicated, the costs may be minimal. 
  • A complete evaluation for most seizuring patients involves extensive (and expensive) diagnostic tests. 
  • Emergency fees and hospitalization costs may be considerable. 

Special risks

  • The following drugs are contraindicated and should be used with extreme caution in rabbits with a recent or previous history of seizures: 
    • Acepromazine Acepromazine maleate.
    • Xylazine Xylazine.
    • Metoclopramide Metoclopramide is relatively contraindicated in epileptic patients. Assess use based on gut motility and clinical appearance of the rabbit.
    • Bronchodilators such as aminophylline, terbutuline, theophylline may lower seizure threshold.
  • Care with prescribing the following drugs:
    • Dexamethasone is contraindicated in rabbits with infectious diseases. Rabbits are steroid-sensitive so only prescribe based on an individual case basis.
    • Albendazole/fenbendazole has been associated with immunosuppression and albendazole has been associated with bone marrow toxicity in rabbits.
    • Cimetidine, ranitidine and chloramphenicol may decrease the metabolism of phenobarbital.
    • Steroid therapy if indicated on clinical findings such as brain edema or CNS signs should be used with extreme caution in rabbits due to immunosuppressive effects and exacerbation of subclinical bacterial infections Therapeutics: glucocorticoids:
      • Corticosteroid use can be detrimental in rabbits.
      • Severe pathological changes can occur even with small, one off doses.
      • Careful consideration of use and monitoring should ensue if corticosteroids must be used.

Pathogenesis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Sequelae

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Meredith A L & Richardson J (2015) Neurological diseases of rabbits and rodents. J Exotic Pet Med 24 (1), 21-33 VetMedResource.
  • Sieg J, Hein J, Jass A et al (2012) Clinical evaluation of therapeutic success in rabbits with suspected encephalitozoonosis. Vet Parasitol 187 (1-2), 328-332 PubMed.
  • Keeble E J (2011) Companion animal practice: encephalitozoonosis in rabbits – what we do and don’t know. In Pract 33 (9), 428-435 VetMedResource.
  • Gruber A, Pakozdy A, Weissenböck H et al (2009) A retrospective study of neurological disease in 118 rabbits. J Comp Pathol 140 (1), 31-37 PubMed.
  • Künzel F, Gruber A, Tichy A et al (2008) Clinical symptoms and diagnosis of encephalitozoonisis in pet rabbits. Vet Parasitol 151 (2-4), 115-124 PubMed.
  • Towfighi J, Housman C, Brucklacher R et al (2004) Neuropathology of seizures in the immature rabbit. Brain Res Dev Brain Res 152 (2), 143-152 PubMed
  • Harcourt-Brown F M & Holloway H K (2003) Encephalitozoon cuniculi in pet rabbits. Vet Rec 152 (14), 427-431 PubMed
  • Kosecki S M (2003) Metoclopramide. Comp Cont Educ Pract Vet 25 (11), 826-828 VetMedResource
  • al-Hader A, Hasan M & Hasan Z (1992) The comparative effects of propofol, thiopental, and diazepam, administered intravenously, on pentylenetetrazol seizure threshold in the rabbit. Life Sci 51 (10), 779-786 PubMed.
  • Young R S, During M J, Aquila W J et al (1992) Hypoxia increases extracellular concentrations of excitatory and inhibitory neurotransmitters in subsequently induced seizure: in vivo microdialysis study in the rabbit. Exp Neurol 117 (2), 204-209 PubMed.
  • Shell L G & Saunders G (1989) Arteriosclerosis in a rabbit. JAVMA 194 (5), 679-680 PubMed.
  • Bergmann F, Costin A, Chaimovitz M et al (1970) Seizure activity evoked by implantation of ouabain and related drugs into cortical and subcortical regions of the rabbit brain. Neuropharmacology 9 (5), 441-449 PubMed

Other sources of information

  • Keeble E (2014) Nervous System and Musculoskeletal Disorders. In: BSAVA Manual of Rabbit Medicine. Eds: Meredith A & Lord B. BSAVA, UK. pp 214-231.
  • Varga M (2014) Infectious Diseases. In: Textbook of Rabbit Medicine. 2nd edn. Butterworth Heinemann Elsevier, UK. pp 435-471.
  • Oglesbee B (2011) Seizures. In: Blackwell’s Five-Minute Veterinary Consult: Small Mammal. 2nd edn. Wiley Blackwell, UK. pp 512-513.
  • Deeb B J & Carpenter J W (2004) Neurologic and musculoskeletal diseases. In: Ferrets, Rabbit and Rodents: Clinical Medicine and Surgery. Eds: Quesenberry K E & Carpenter J W. Saunders, St. Louis. pp 203-210. 
  • Lorenz M D & Kornegay J N (2004) Oliver & Lorenzs Handbook of Veterinary Neurology. 4th edn. Saunders, St Louis.
  • Harcourt-Brown F (2002)Textbook of Rabbit Medicine.Butterworth Heinemann, Edinburgh.
  • Fox N & Bourne D (Online) Epilepsy and Convulsions in Bears, Lagomorphs and Great Apes. Website: wildpro.twycrosszoo.org.  Last accessed 22nd March 2018.


ADDED