Epilepsy in horses: aetiological classification and predictive factors.

The research paper presents an extensive investigation into epilepsy in horses, conducted at the Ohio State University Veterinary Medical Center. The study aimed to categorize horse seizures based on their causes and also delineate the characteristics of epilepsy in horses.

Methodology

• The research was a retrospective observational study examining 104 horses that were presented with seizure symptoms at the Veterinary Medical Center between 1988 and 2009.
• These seizures were classified according to their aetiology, i.e., the cause or origin, using various means such as the horse’s medical history, clinical observations, diagnostic investigations like electroencephalograms (EEG), cerebrospinal fluid analysis, computed tomography (CT) scan of the head, and post-mortem examinations where applicable.
• To identify patterns and relationships, the researchers utilized both univariate (examining one variable at a time) and multivariate (examining multiple variables simultaneously) logistic regression analyses.

Results

• The study found that 70% of the cases presented more than two recurrent seizures, fulfilling the criteria for epilepsy diagnosis.
• The seizures were further categorized as symptomatic, where there was identifiable structural brain damage (35.6% of cases), cryptogenic with no known origin (54.8% of the cases), and idiopathic believed to have a potential genetic predisposition (2.7% of the cases).
• The study also identified three key factors strongly correlated (P<0.05) with epilepsy on univariate analysis: horses with regular neurological examination on admission, occurrence of seizures unprovoked by any known factors, and the presence of sudden epileptiform activity on EEG recordings.
• However, when considering the type of seizure, the likelihood of a horse with generalized seizures having epilepsy was found to be seven times lower than a horse with partial seizures, according to multivariate modeling.

Conclusions

• The findings indicated that in most cases, the aetiology of the seizures was symptomatic or cryptogenic. Reactive seizures and idiopathic epilepsy were found to be relatively less common among the studied horse population.
• This research represents a pioneering attempt to systematically classify seizures and characterize the nature of epilepsy in horses.
• The predictive factors for horse epilepsy identified in this study were similar to those reported in other species.
• The identification and understanding of these core factors may help veterinary clinicians make early and accurate diagnoses of epilepsy in horses.