International veterinary epilepsy task force consensus proposal: diagnostic approach to epilepsy in dogs

Abstract

This article outlines the consensus proposal on diagnosis of epilepsy in dogs by the International Veterinary Epilepsy Task Force. The aim of this consensus proposal is to improve consistency in the diagnosis of epilepsy in the clinical and research settings. The diagnostic approach to the patient presenting with a history of suspected epileptic seizures incorporates two fundamental steps: to establish if the events the animal is demonstrating truly represent epileptic seizures and if so, to identify their underlying cause. Differentiation of epileptic seizures from other non-epileptic episodic paroxysmal events can be challenging. Criteria that can be used to make this differentiation are presented in detail and discussed. Criteria for the diagnosis of idiopathic epilepsy (IE) are described in a three-tier system. Tier I confidence level for the diagnosis of IE is based on a history of two or more unprovoked epileptic seizures occurring at least 24 h apart, age at epileptic seizure onset of between six months and six years, unremarkable inter-ictal physical and neurological examination, and no significant abnormalities on minimum data base blood tests and urinalysis. Tier II confidence level for the diagnosis of IE is based on the factors listed in tier I and unremarkable fasting and post-prandial bile acids, magnetic resonance imaging (MRI) of the brain (based on an epilepsy-specific brain MRI protocol) and cerebrospinal fluid (CSF) analysis. Tier III confidence level for the diagnosis of IE is based on the factors listed in tier I and II and identification of electroencephalographic abnormalities characteristic for seizure disorders. The authors recommend performing MRI of the brain and routine CSF analysis, after exclusion of reactive seizures, in dogs with age at epileptic seizure onset <6 months or >6 years, inter-ictal neurological abnormalities consistent with intracranial neurolocalisation, status epilepticus or cluster seizure at epileptic seizure onset, or a previous presumptive diagnosis of IE and drug-resistance with a single antiepileptic drug titrated to the highest tolerable dose.This consensus article represents the basis for a more standardised diagnostic approach to the seizure patient. These recommendations will evolve over time with advances in neuroimaging, electroencephalography, and molecular genetics of canine epilepsy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0462-1) contains supplementary material, which is available to authorized users.

Comparing the effects of first‐line antiepileptic drugs on the gait of dogs with idiopathic epilepsy

“…Dogs with IE were required to fit Tier I or Tier II confidence level of IE diagnosis (De Risio and others 2015). In brief, Tier I dogs had a history of two or more epileptic seizures with unremarkable interictal physical and neurological examination with normal bloodwork and urinalysis.…”

Magnetic resonance imaging findings in epileptic cats with a normal interictal neurological examination: 188 cases

“…They arise through disturbances in forebrain function and can be caused by metabolic derangements, by genetic or acquired abnormalities in neuronal function or by structural brain disease (Berg and others 2011, Muñana 2013, Finnerty and others 2014, Pakozdy and others 2014, Wahle and others 2014, Berendt and others 2015). The diagnostic approach to cats with epileptic seizures includes complete physical and neurological examinations, analysis of various biochemical and haematological parameters, advanced imaging of the brain and analyses of cerebrospinal fluid (CSF) when appropriate (Rusbridge 2005, Smith Bailey and Dewey 2009, De Risio and others 2015). …”

“…An increased likelihood of a significant brain lesion with age has been established in neurologically normal dogs with recurrent seizures, and studies have indicated a substantially higher risk in dogs older than six years of age, which is primarily related to the higher prevalence of neoplastic lesions in older animals (Smith and others 2008, Schwartz and others 2013, Armasu and others 2014, De Risio and others 2015). …”

“…In accordance with the International Veterinary Epilepsy Task Force (IVETF) guidelines for dogs (De Risio and others 2015), the authors divided the cats into three age groups (aged or younger than one year, between one and six years and older than six years) and compared the proportion of cats with a detectable lesion on MRI in these different groups. They also analysed whether there was an optimal cut-off age at which structural epilepsy was more prevalent than idiopathic epilepsy and assessed the association of age with the likelihood of suffering from structural epilepsy.…”

Novel approach to magnetic resonance imaging of epileptic dogs — T2 relaxometry of the brain with emphasised hippocampus

“…For the presumptive diagnosis of primary epilepsy, all dogs met the requirements of the tier I confidence level by De Risio, besides laboratory tests being performed on each dog (De Risio et al, 2015).…”