Epilepsy in Dogs - Symptoms, Treatment, and How to Respond

Just like people, dogs can have epileptic seizures. These episodes are characterized by brief convulsions, and it's important to understand this condition well so we can recognize it if our dog has an episode.

Below, we'll explain the main features of epilepsy in dogs, to understand how it happens, how to recognize it, and what its treatment is.

What is canine epilepsy?

Epilepsy is a brain disorder characterized by repeated seizures over time.

A dog can have a seizure as a one-off event from various causes, but we only call it epilepsy when seizures happen repeatedly over a period of time.

Why do seizures happen in epilepsy?

Seizures are caused by an electrical storm in the brain. Brain cells (neurons) use electrical and chemical signals to communicate with each other. This communication can be excitatory (activating the next neuron) or inhibitory (switching off the next neuron). If the brain's balance tips too far toward excitation, many neurons can become overexcited, and a seizure can occur.

What types of epilepsy affect dogs?

• Secondary or symptomatic epilepsy: If we can identify the cause of the seizures, such as a brain tumor or a stroke, we say the dog has symptomatic (or secondary) epilepsy. In other words, the seizures are a symptom of an identified disease.
• Idiopathic or primary epilepsy: If there's no cause that explains the seizures, we call it idiopathic (or primary) epilepsy. In these cases there's no detectable structural lesion in the brain, and it's classified as a genetic condition.

What symptoms does epilepsy cause?

The defining symptom of epilepsy is seizures, and there are two main types: generalized and focal (or partial).

Generalized seizures

In a generalized seizure, an electrical storm occurs across the whole brain, and the classic episode has three phases:

• Aura or prodrome: there's a change in the pet's behavior that alerts the owner that a seizure is about to happen. The dog seems scared, dazed, may seek out their owner's attention, or try to hide.
• Seizure: the dog goes rigid, falls to one side with legs stiff and head thrown back, drools excessively, urinates, defecates, vocalizes, and paddles all four legs (jerking motions). Once the seizure has started, the dog is no longer conscious and feels no pain. It's brief (30-90 seconds). If a seizure lasts much longer, it's an emergency requiring urgent treatment with rectal diazepam, always under veterinary guidance.
• Post-ictal behavior: After the seizure, the dog may stay motionless for a while. Eventually, they get back up and may seem blind or disoriented during this phase, bumping into things along the way. Sometimes they show a strong appetite and thirst. On rare occasions they act aggressively during this period, so precautions should be taken, especially if there are children at home. This post-ictal behavior usually resolves within a few hours, and the dog returns to normal.

Focal or partial seizures

In focal or partial seizures, the electrical storm starts in an isolated area of the brain and affects the movement of the body part controlled by that region.

The face is the area most often affected (twitching or blinking). If the seizure spreads, other parts of the body will become involved. For example, a front leg may start to twitch and curl.

During a focal seizure, the dog is usually conscious and may try to seek out their owner, confused by what's happening to them. A focal seizure can either stop or generalize. If it generalizes, the pet loses consciousness and has a generalized seizure.

What determines when a dog will have seizures?

It's not known for certain what determines when an epileptic dog will have a seizure; we can say epilepsy is, by nature, unpredictable.

Some dogs have seizures regularly with no link to any external factor, while in others, seizures seem to be triggered by specific events like stress or changes in weather.

The most common time for a dog to have a seizure is when they're relaxed and calm. They can even happen during deep sleep.

How is idiopathic epilepsy diagnosed?

Idiopathic epilepsy is diagnosed by ruling everything else out — that is, the vet looks for possible causes of seizures (sometimes running additional tests: EEG, brain CT scan, spinal tap…), and if none are found, a diagnosis of idiopathic epilepsy is made.

Age of onset and the seizure pattern (type and frequency) are the two most important factors taken into account when diagnosing this condition. Idiopathic epilepsy usually appears in animals between 6 months and 5 years old.

Since seizures don't usually happen in front of the vet, it's very important to describe what happens during the seizure episode in as much detail as possible, or even record it on video.

This helps the vet determine whether these events are truly epileptic seizures, since other issues like fainting or dizziness can also come and go in a way that resembles seizures and can look similar to epilepsy.

How is canine epilepsy treated?

If the epilepsy is secondary, treating the underlying disease (for example, removing a brain tumor) may cure the epilepsy. However, in most cases we can't find the cause (idiopathic epilepsy), so medication is needed to control the seizures.

It's important to understand that anti-epileptic medications don't cure epilepsy, so treatment is usually lifelong. The goal of treatment is to reduce the number and severity of seizures.

There's no single medication or specific dose that works as a general treatment for every dog — instead, therapy needs to be tailored to each dog's specific needs. This often requires a trial-and-adjustment period to find the medication and dose that work best for each individual case.

The most commonly used medications in dogs are phenobarbital, potassium bromide, and diazepam. They all work by increasing inhibition in the brain, making seizures less likely. They can have side effects such as sedation and increased appetite.

Which breeds are predisposed to idiopathic epilepsy?

• Epileptic parents: Many dogs with idiopathic epilepsy have inherited this condition from their parents. It's epilepsy caused by a mutation in a specific gene passed down from parents to offspring.
• Certain breeds are predisposed to developing epilepsy: Some breeds have shown hereditary epilepsy. The main breeds identified as predisposed are: Beagle, various herding/shepherd breeds, Boxer, Cocker Spaniel, Collie, Dachshund, Irish Setter, Irish Wolfhound, Keeshond, Labrador Retriever, Poodle, Saint Bernard, Shetland Sheepdog, Siberian Husky, Springer Spaniel, Welsh Corgi, and Wire Fox Terrier.

One of the main goals of the scientific research currently being done on canine epilepsy is to identify the genes responsible for epilepsy in dogs. This will let us positively diagnose the hereditary form and take steps to reduce the incidence of epilepsy in dogs.

Bibliography Carlson and Giffin. 2002. Manual práctico de veterinaria canina. Madrid. Editorial el Drac.