What is a Seizure and Why Does it Happen?


A seizure (the medical term for a fit or convulsion) occurs when there is a sudden burst of electrical activity in the brain which causes a temporary disruption in the normal messaging processes. Seizures occur as a result of abnormal electrical activity within the brain that cause dog’s muscles to contract and relax rapidly.


Seizures can be partial or focal; initially affecting certain parts of the brain and can then become generalized. Observing how your pet behaves during a seizure can help the vet when making a diagnosis.

Different Types and Causes of Seizure

The brain affects the whole of the body. Which parts of the body are affected depends on where in the brain the seizure occurs.

There are many different types of seizures and loads of different causes. Any head injury or stress to the brain can cause fitting; as can brain tumours, poisoning, low blood sugar levels, calcium deficiency,  lack of oxygen, kidney or liver disease, raised body temperature e.g. due to heat stroke or infection, stroke, epilepsy etc.


A diagnosis of epilepsy is made when there has been at least one seizure that cannot be attributed to any other cause. It can be difficult to control epileptic seizures in dogs.

What does a seizure look like?

Seizures can cause dogs to collapse and experience rigid, out of control movements. There are absence seizures, where dogs go rigid and unresponsive, and tonic/clonic fits where dogs will thrash around. Seizures can be anything in between.Seizures

What To Do

  • Protect your pet from danger and anything against which they could hurt themselves. Move furniture to clear the area if necessary.
  • Keep lighting low, noise to a minimum and avoid touching them too as external distractions can prolong a seizure.
  • Do not put anything in their mouth.
  • Make a note of the time the seizure started and exactly what happened. This may be useful for the vet to diagnose the cause of the fit.
  • Once the seizure is over your pet could be disorientated for a while (up to 2 hours), they are also likely to be thirsty so ensure they have access to drinking water.
  • Keep your hands clear of their mouth and never put anything in or near their mouth during a seizure.
  • Call your vet.

Most seizures are over very quickly, within 2 or 3 minutes. Ideally, let your pet finish their convulsion before attempting to transport them. If there are multiple seizures in quick succession or the seizure is lasting longer than 5 minutes, you should contact the vet immediately as they may need veterinary intervention to stop the seizure. Whilst your pet is having a seizure there is a reduced oxygen supply to the brain which is why prolonged or continuous seizures can be life-threatening.

Seizures can be very different, but they often begin with trembling, their eyes glazing over and stopping responding to you. They may then fall down and start to jerk violently. During a seizure it is common for dogs to urinate or defecate and they may drool excessively. This could be blood-stained if they have bitten their tongue.

After the seizure, your dog may be disoriented or sleepy for up to a couple of hours.


First Aid for Pets provides this information for guidance and it is not in any way a substitute for veterinary advice. The author does not accept any liability or responsibility for any inaccuracies or for any mistreatment or misdiagnosis of any person or animal, however caused. It is strongly advised that you attend a practical First Aid for Pets course or take our online course to understand what to do in a medical emergency.

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