What Causes Seizures in Dogs?

Witnessing your dog have a seizure is one of the scariest things that can happen to a pet owner. Although seizures are not painful, they look frightening and can cause you and your dog to panic. And your dog having a seizure is only made more frustrating if you don’t know why they are happening. This post will discuss the many different potential causes of seizures in dogs as well as some treatment strategies.

What causes seizures in dogs?

What is a seizure?

A seizure is a temporary, involuntary disturbance of normal brain function that is usually accompanied by uncontrollable muscle activity. Seizures, sometimes referred to as convulsions or fits, are actually one of the most frequently reported neurological conditions in dogs.

Canine epilepsy is a condition that refers to repeated episodes of seizures. Seizures can occur once or occur in clusters, and can be infrequent and unpredictable or occur at regular intervals.

What is a seizure in dogs?

What Causes Dogs to Have Seizures?

There are many potential causes of seizures in dogs. These include:


A condition that is characterized by seizures, epilepsy is the most common cause of seizures in dogs under the age of five. Epilepsy is a disorder of the brain that can cause dogs to have sudden and uncontrollable physical attacks, or seizures. Sometimes, the dog will lose consciousness, while other times, the dog will be awake the entire time.

The term “epilepsy” is itself becoming rapidly outdated because it implies that it is a single condition, however epilepsy most likely involves several conditions that cause the seizures. And just because a dog has a seizure does not mean it has epilepsy. Epilepsy can be idiopathic or the result of genetic abnormalities. If untreated, a dog’s seizures could become more frequent and severe. Younger dogs also tend to have more violent seizures.

Epileptic seizures come in two forms: primary and secondary. Primary, or idiopathic seizures have no known source, although genetic factors may be suspected. An external influence causes secondary seizures and the source is known. Epileptic seizures can cause the dog to fall on its side, become stiff, salivate, urinate, defecate, chomp its jaw or paddle with all four limbs. They generally last anywhere from 30 to 90 seconds.

Epilepsy dog seizure

Brain Tumor

There are two main types of brain tumors, or abnormal growths in the brain: primary and metastases. Primary tumors grow from tissues in the brain while metastases are spread through the bloodstream from tumors found elsewhere in the body. Tumors can be malignant and may also put pressure on the brain as it grows, causing loss of vision, motor coordination and sometimes, seizures.

Cancer growths in dogs can form on the brain or the pituitary gland, and can affect how your dog behaves and functions. Seizures can often accompany this abnormal behavior. An altered mental state, oversensitivity to pain and problems with vision are all signs of the presence of a brain tumor. Tumors are thought of as “intracranial” causes of seizures, and more commonly seen in older dogs (over five years). A brain tumor only accounts for three percent of all seizures in dogs.

brain tumor dog seizure

Head Injury

A significant injury to the skull could cause dog seizures as well. The injury would probably have cracked the skull, and your dog would not have the seizures right away. They might not be seen until weeks or even months after the initial injury.

Anticonvulsant drugs will not be effective against seizures caused by injury. The drugs are designed to stabilize the neurons within brain cells, but in the case of an injury, the neurons are already stable. The injury itself is causing the seizures because of a “cerebral scar” that shows up on an MRI as an “abrasion” on the skull. This scar or abrasion is an area that forms where the brain tissue has died and puts pressure on the brain, which causes the seizures.

Seizures as the result of injury can have severe detrimental effects to your dog’s health. They can increase the pressure within the brain and constrict blood flow, making the initial injury worse.

head injury dog seizure

Lyme Disease and Rocky Mountain Spotted Fever

These two diseases are caused by ticks. The tick bite causes Lyme Disease or Rocky Mountain Spotted Fever by transferring bacteria into the dog. If the tick is found within 24 hours after attaching to your dog, the chance of infection is very small. However, if your dog does get infected with Lyme Disease, it could develop seizures as a symptom.


Another one of the many canine viral diseases, canine distemper virus (CDV) can also cause seizures. Puppies most often develop CDV when they are between three and eight months old, because that is the time when they lose their maternal antibodies.

Puppies that have not been vaccinated or live in a kennel or shelter are most at risk for developing CDV. There is no cure for canine distemper, but vaccinations can prevent a dog from developing the disease. The death rate can reach as high as 80 percent, according to the American Veterinary Medical Association.

CDV is usually transmitted through the air, but it can also be transmitted through physical contact with saliva, urine, feces, and even human hands. Most often, dogs get CDV from an animal that is already infected or from a human hand that carried the virus.

distemper dog seizure

Environment and Toxins

Despite your best efforts to dog-proof your home, your dog can get into things that are toxic and can lead to seizures. There are also certain plants and things outside that will also be toxic to your dog. It’s best to carefully remove these items or keep them where your dog can’t get to them, but still, it happens.

Ingesting harmful chemicals or plants can lead to the onset of seizures. Some substances that are toxic to your dog and can induce seizures include antidepressants, tobacco, aspirin, alcohol, marijuana, drain cleaners, gasoline, insecticides, and furniture polish.

Natural substances found outside include horse chestnuts, venomous snakes, the brown recluse spider, the Colorado River toad, the Florida marine toad, Russian Olive trees, Codeless, pine trees, spreading junipers, apple trees and apples in the fall, plenty of grass, mushrooms when it is damp, many birds, garter snakes, and more. When you take your dog outdoors, make sure to keep an eye on them.

It is important to keep an eye on your dog when outdoors, and to keep medications and certain substances out of his reach.

What causes seizures in dogs?

Hypoglycemia (Low Blood Sugar)

Dogs with low blood sugar are also vulnerable to seizures. Hypoglycemia can be caused by a pancreatic tumor, liver disease, a cortisone deficiency and an accidental insulin overdose to a