title: Epilepsy in horses: aetiological classification and predictive factors.
abstract: BACKGROUND
  In contrast with reports in man and small animals, a systematic classification of seizures in horses is lacking.
  
  
  OBJECTIVE
  The purpose of this study was to classify seizures based on their aetiology and to characterise epilepsy in 104 horses presented for seizures at the Ohio State University Veterinary Medical Center between 1988 and 2009.
  
  
  METHODS
  In a retrospective observational study, seizures were classified by aetiology based on history, clinical observations, diagnostic investigations (e.g. electroencephalograms, cerebrospinal fluid and computed tomography imaging of the head) and post mortem examinations, when available. Univariate and multivariate logistic regression analyses were performed.
  
  
  RESULTS
  Epilepsy (i.e. 2 or more recurrent seizures) was identified in 70% of cases, and further classified as symptomatic (i.e. structural brain pathology, 35.6% of cases), cryptogenic (i.e. unknown, 54.8% of cases) and idiopathic (i.e. suspected genetic predisposition, 2.7% of cases). Normal neurological examination on admission, the presence of seizures unprovoked by any identified factors and paroxysmal epileptiform activity on electroencephalogram recordings were all strongly (P<0.05) correlated with epilepsy on univariate analysis. For a horse with generalised seizures, the odds of having epilepsy was 7 times lower compared with a similar horse with partial seizures (P<0.05) in multivariate modelling.
  
  
  CONCLUSIONS
  Seizure aetiology was symptomatic or cryptogenic in most horses, whereas reactive seizures and idiopathic epilepsy were less common.
  
  
  CONCLUSIONS
  This study is the first attempt to classify seizures and to characterise epilepsy in a referral-based equine population. Predictive factors of epilepsy in horses were similar to those reported in other species and may assist the clinician with the early diagnosis of epilepsy.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA. lacombe.2@osu.edu
authors.forename: V A
authors.initials: VA
authors.lastname: Lacombe
authors.forename: M
authors.initials: M
authors.lastname: Mayes
authors.forename: S
authors.initials: S
authors.lastname: Mosseri
authors.forename: S M
authors.initials: SM
authors.lastname: Reed
authors.forename: W R
authors.initials: WR
authors.lastname: Fenner
authors.forename: H T
authors.initials: HT
authors.lastname: Ou
mesh_terms: D000818:Animals; D004827:Epilepsy / Q000145:classification / Q000662:veterinary*; D005260:Female; D006734:Horse Diseases / Q000145:classification*; D006736:Horses; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies