What Causes Seizures in Dogs?

common causes of dog seizures illustration

Illustration: The Spruce 

Seizures can occur in dogs for many different reasons. A seizure occurs when the cerebral cortex, a part of the brain, functions in an abnormal way. The cause of this malfunction may be a result of an abnormality located within the brain itself, or it could be the result of a disease that starts in another part of the body but is still is able to affect the brain. Seizures can be a sign of serious health issues in your pet. If your dog is experiencing seizures you should take them to the vet immediately. 

Extracranial Causes of Seizures in Dogs

Extracranial causes of seizures are the causes that originate elsewhere in the body but are still able to affect the dog's brain and cause seizure activity. The seizure occurs because either the metabolism or the electrophysiology of the brain is changed by the disease.

In most extracranial cases of seizures, the entire cerebral cortex is affected resulting in a generalized seizure rather than a focal or partial seizure. The most common extracranial causes of canine seizures are:

  • Hypoglycemia (low blood sugar level)
  • Liver disease (also termed hepatic encephalopathy)
  • Hypocalcemia (low blood calcium level)
  • Hypothyroidism (disease of the thyroid gland that causes abnormally low thyroid hormone production)
  • Poisons, including organophosphates, chocolate (theobromine), caffeine, strychnine, and others
  • Hyperthermia (elevated body temperature, "heat exhaustion")
  • Toxoplasma

Intracranial Causes of Canine Seizures

Intracranial causes of seizures are diseases that cause either structural or functional changes inside of the dog's brain. Common intracranial causes of canine seizures that cause structural changes in the brain include:

  • Idiopathic Epilepsy (unknown cause, presumed genetics)
  • Brain tumors
  • Granulomatous Encephalitis (inflammatory/autoimmune disease)
  • Cerebral infarction (lack of blood flow to part of the brain)
  • Trauma to the brain
  • Congenital disease such as hydrocephalus
  • Degenerative brain conditions such as storage diseases
  • Infectious diseases such as canine distemper virus infection (CDV), rabies and other viral, bacterial, fungal, protozoal or rickettsial infections
  • Nutritional imbalances such as thiamine deficiency

In most cases, if the cause of your dog's seizures is a structural intracranial lesion, the disease will be progressive. This means it will get worse with time.

Functional changes inside of your dog's brain may result in what is known idiopathic epilepsy. Idiopathic Epilepsy (unknown cause/genetic) is a disease in which your dog has recurrent seizures but no specific cause can be located for the seizures.

If Your Dog Has Had a Seizure

If your dog has had a seizure, he or she should be examined by your veterinarian. In some cases, diagnostic tests will indicate a clear cause for the seizure or seizures. Where no cause can be located, the disease is diagnosed as idiopathic epilepsy. Together you and your vet can make a health plan to deal with your pet's seizures. While seizures can be scary they are usually not life-threatening. Your vet can teach you what to do if your dog is having seizure's and in some cases can provide medicine to make them stop. 

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Brauer, Christina. Jambroszyk, Melanie. Tipold, Andrea. Metabolic and toxic causes of canine seizure disorders: A retrospective study of 96 cases. The Veterinary Journal, Volume 187, Issue 2, pp.272-275, 2011. doi:10.1016/j.tvjl.2009.10.023

  2. Lavely, James A. Pediatric seizure disorders in dogs and cats.The Veterinary clinics of North America. Small animal practice, vol. 44,2 (2014): 275-301. doi:10.1016/j.cvsm.2013.10.004

  3. Kritikos G, Parr JM, Verbrugghe A. The Role of Thiamine and Effects of Deficiency in Dogs and CatsVeterinary Sciences, 2017; 4(4):59. doi:10.3390/vetsci4040059