Epilepsy and Seizures in Dogs

What Can Cause a Seizure?

A seizure does not automatically mean that a dog has idiopathic epilepsy. Possible causes include:

• Idiopathic epilepsy, where no underlying cause is identified
• Poisoning or an adverse reaction to a substance
• Low blood sugar or an electrolyte disturbance
• Liver or kidney disease
• Head injury
• Inflammation or infection affecting the brain
• A structural brain abnormality or tumour

Idiopathic epilepsy is often presumed to have a genetic component and commonly begins in younger adult dogs.

A structural brain lesion is not a feature of idiopathic epilepsy; finding a lesion suggests a different underlying cause.

What a Seizure May Look Like

A generalised seizure may cause collapse, loss of awareness, stiffening, paddling of the limbs, jaw movements, drooling and loss of bladder or bowel control.

Focal seizures affect only part of the brain and may cause twitching of one area, unusual movements, repeated swallowing, staring or sudden changes in behaviour. Awareness may be retained.

1. Before the seizure: some dogs become restless, anxious, clingy or withdrawn, although there may be no warning.
2. During the seizure: abnormal movements, behaviour or awareness occur. Time the episode from the moment it begins.
3. After the seizure: the dog may be confused, restless, hungry, thirsty, weak or temporarily unable to see. This recovery period may last from minutes to several hours.

Diagnosis

Your vet will ask about the episode, the dog’s age, health, medication and possible exposure to toxins. A video and a written seizure diary can be extremely helpful.

Initial tests often include blood and urine tests. Depending on the dog’s age, examination and results, further investigation may include bile-acid testing, MRI or CT imaging, and analysis of cerebrospinal fluid.

Idiopathic epilepsy is a diagnosis of exclusion, made after other likely causes have been considered or ruled out.

Treatment

Not every dog is started on long-term medication after one short seizure. The decision depends on seizure frequency, duration, severity, clustering, recovery and the suspected cause.

Medicines used in dogs can include phenobarbital, imepitoin, potassium bromide, levetiracetam and zonisamide. The most appropriate choice varies between dogs.

Your vet may also prescribe emergency medication to use at home if a seizure becomes prolonged or seizures occur in clusters. Use it only according to the instructions provided for your dog.

Medication and Monitoring

Anti-seizure medication must be given consistently and at the prescribed times. Do not stop it suddenly or change the dose without veterinary advice, as this can trigger severe seizures.

Some medicines require regular blood tests to measure drug levels and monitor liver or other organ function.

Increased thirst, hunger, urination, sleepiness or unsteadiness can occur when treatment begins, but persistent or severe side effects should be reported to the vet.

Keep a diary recording the date, time, length and features of every seizure, medication changes and possible triggers. This helps the vet assess whether treatment is working.

Outlook

Many dogs respond well to treatment and lead happy, active lives. Some continue to have occasional breakthrough seizures and need their treatment adjusted over time.

Dogs with frequent cluster seizures, status epilepticus or an underlying brain disease may have a more guarded outlook and may benefit from referral to a veterinary neurologist.