Epileptic Seizures and their Mimics

Epileptic seizures are one of the most common neurological presentation in dogs and cats. They can be generalized or partial depending on the brain being affected on both sides from the start or only in one specific area respectively. Although increasingly being recognized, paroxysmal dyskinesias (PDs) are often poorly characterised in the veterinary literature and are commonly mistaken for an epileptic seizure, both by owners and by vets. PDs are episodic movement disorders in which abnormal movements are present only during attacks. Between attacks, dogs are neurologically normal and there is no loss of consciousness during the attacks, though some dogs find the episodes disconcerting and do not respond normally. The attacks can last anything from a few minutes to a couple of hours and can sometime occur in clusters. Dogs and people with PD are therefore often misdiagnosed as having unusual epileptic seizures (in some types of seizure, the patient remains conscious – as in an attack of PD). Other mimics of epileptic seizures can be non-neurological (e.g. metabolic or cardiovascular events such as syncope) or neurological (myokymia, narcolepsy/cataplexy, vestibular attack and exercise-induced collapse syndrome). Correct identification of the exact nature of the paroxysmal event is therefore fundamental. A thorough description of the event, especially if supported by video footage, can provide important information about the speed of onset of neurological signs, potential loss of consciousness/awareness during the events and type of activity the patient was performing at the time of the ‘episode’.