Dog Seizures: Causes, Types and What To Do If Your Dog Has One

By: Sarah Wooten, DVM, CVJUpdated:

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Dog Seizures: Causes, Types and What To Do If Your Dog Has One

Watching a dog have a seizure is a terrifying event for most pet parents. If you have ever experienced this, you may wonder what causes dogs to have seizures?

What Causes Dogs to Have Seizures?

The causes of seizures in dogs, people and other mammals are abnormal electrical activity in the brain. Seizures can vary in appearance based on what part of the brain is affected.

When neurons start uncontrollably firing and wiring together, the body responds with twitches, jerks, convulsions and altered or loss of consciousness. A dog experiencing a seizure also may urinate or defecate involuntarily, drool, become temporarily blind, stop responding to his name and act drunk and wobbly due to the abnormal electrical activity happening in his brain.

The problem with abnormal electrical activity in the brain is that the more the neurons fire together, the stronger their connection becomes, and the brain develops a repeated pattern of firing abnormal electrical activity, resulting in seizures.

Types of Seizures

In veterinary medicine, seizures are grouped into two large categories:

  1. Seizures that have intra-cranial causes (the cause is inside the head)
  2. Seizures that have extra-cranial causes (the cause is due to a problem somewhere else in the body)

Let’s discuss each one.

Intra-cranial Seizures

Intra-cranial seizures can be caused by many things, including tumors that press on brain tissue, stroke, hydrocephalus (water on the brain—a condition seen in dome-headed breeds such as Chihuahuas), infected or inflamed brain tissue, brain parasites or brain trauma. All of these conditions create abnormal electrical activity in the brain that can result in seizures.

One of the most common causes of seizures in dogs is idiopathic epilepsy. Epilepsy is particularly frustrating because there are no anatomical abnormalities in the brain and no extra-cranial causes, but the dog still experiences unexplained seizures.

Extra-cranial Seizures

Extra-cranial seizures can be caused by low blood sugar in very young animals or diabetics, low blood calcium, acute kidney failure, liver disease, heat stroke and toxins, such as snail bait or strychnine. The brain needs sugar to function. When blood sugar drops, the brain stops working correctly and causes seizures or loss of consciousness.

Calcium is important in the electrical activity of cells. When blood calcium drops, it causes a condition called “tetany” where the muscles twitch, which can mimic the signs of a seizure.

Kidney failure and liver disease both result in a buildup of toxins in the blood that negatively impact brain cells. When the brain cells get angry from being exposed to toxins, seizures can occur.

What Dog Seizures Look Like

Seizures are further classified into categories based on how they affect the dog:

  • A generalized grand mal seizure involves convulsing and loss of consciousness.
  • A partial seizure occurs when only one part or one side of a dog’s body is seizing and the dog remains conscious and responsive, indicating that only part of the brain is affected.
  • Narcolepsy, which is excessive sleepiness during the day—especially after playing or eating—is considered a seizure disorder, as well as obsessive-compulsive disorders, such as fly biting, flank sucking or other strange behaviors.
  • Cluster seizures are seizures that occur close together in time—within 24 hours of each other for example—and are considered life-threatening. Equally life threatening is status epileptus, which is defined as continuous seizure activity for more than 30 minutes.

What To Do If Your Dog Has a Seizure

If your dog experiences seizures, seek veterinary attention as soon as possible. The more a dog experiences seizures, the more established those abnormal electrical pathways become in the brain, which increase the likelihood of additional seizures, so it is important to identify the cause of the seizures (if possible) and either treat the underlying cause or the seizures themselves as soon as possible. Seizures often resolve once the underlying disease has been treated.

Many pet parents panic and try to move the dog while he is seizing. Don’t do this because you risk injury to yourself and your pet. Instead, make sure your dog is in a safe place where they cannot fall downstairs or into a pool (seizing pets can drown), and then call your veterinarian immediately for further instruction.

Note: During a canine seizure, your dog is not at risk for swallowing his tongue, so prevent accidental bites by never, ever putting your hands or fingers near a seizing dog’s mouth. Wait until the seizure ends, and then calmly take your dog to the veterinarian.

If your dog has been diagnosed with epilepsy, then it is important to talk with your veterinarian about the risk and benefits of getting your pet started on dog seizure medication.


By: Sarah Wooten, DVM, CVJUpdated: