Epilepsy Diagnosis
Understanding your pet's epilepsy diagnosis
What the words actually mean — and what a diagnosis does and doesn't tell you about your pet's future.
A seizure is not a diagnosis — it is a symptom. When your veterinarian tells you your pet has epilepsy, they are telling you that your pet has a condition that causes recurrent seizures. What they are still figuring out is why. Understanding the categories your vet uses can help you ask better questions and make more informed decisions together.
The IVETF classification system
In 2015, the International Veterinary Epilepsy Task Force — a group of veterinary neurology specialists — published a landmark set of consensus guidelines that standardized how epilepsy is classified in dogs and cats. Most veterinary neurologists now use this framework. It divides epilepsy into three main categories based on the underlying cause.
- Idiopathic epilepsy — Seizures with no identifiable underlying cause other than a suspected genetic predisposition. This is the most common type in dogs, particularly in breeds such as Border Collies, Labrador Retrievers, and Belgian Shepherds. It is sometimes called "primary epilepsy."
- Structural epilepsy — Seizures caused by an identifiable abnormality in the brain — such as a tumor, inflammatory disease, or injury. MRI is typically used to identify these changes.
- Epilepsy of unknown cause — Seizures where a thorough workup has not identified a cause, but there is insufficient evidence to classify as idiopathic or structural.
What "idiopathic" actually means
"Idiopathic" is a medical term that essentially means "we don't know the precise cause, but we believe it is intrinsic to the brain — likely genetic." It does not mean your vet has given up or that the diagnosis is incomplete. It means your pet has epilepsy that is not caused by a detectable brain lesion or systemic disease — which is often considered more manageable than epilepsy caused by structural brain disease, because it is more likely to respond to medication.
What "reactive seizures" means
Reactive seizures are not epilepsy. They occur when an otherwise normal brain reacts to a metabolic or toxic trigger — such as low blood sugar, liver disease, toxin exposure, or electrolyte abnormalities. Your vet will typically rule these out with blood and urine testing before considering an epilepsy diagnosis. Treating the underlying cause often resolves reactive seizures.
The definition of epilepsy
According to the IVETF consensus guidelines, epilepsy in companion animals is defined as "a brain disease characterized by an enduring predisposition to generate epileptic seizures." In practical terms, this usually means two or more unprovoked seizures occurring at least 24 hours apart.
- What type of epilepsy does my pet have — idiopathic, structural, or unknown?
- What tests are recommended to rule out structural or reactive causes?
- At what point would you recommend starting medication?
- What does long-term management typically look like for this type?
- Are there breed-specific factors I should know about?
- Berendt M, et al. International veterinary epilepsy task force consensus report on epilepsy definition, classification and terminology in companion animals. BMC Veterinary Research. 2015;11:182. doi.org/10.1186/s12917-015-0461-2
- De Risio L, et al. International veterinary epilepsy task force consensus proposal: diagnostic approach to epilepsy in dogs. BMC Veterinary Research. 2015;11:148. doi.org/10.1186/s12917-015-0462-1
- Volk HA, et al. IVETF consensus reports on epilepsy in companion animals — editorial. BMC Veterinary Research. 2015;11:194. doi.org/10.1186/s12917-015-0460-3
From diagnosis to a daily plan
A new diagnosis is the start of a long road. Here's a map.
Understanding the terminology is step one — the next is turning it into a routine you can actually live with. The Complete Pet Seizure Care System walks from diagnosis through daily management: questions for your vet, medication and seizure tracking, and the wellbeing pieces, all in one place so you're not assembling it from scratch.
Explore the Care System →Help advance pet seizure research
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