Seizures are one of the most common neurological problems in dogs. They occur when the cerebral cortex of the brain functions abnormally, but there are many diseases that can cause seizures in dogs. Sometimes, such as in the case of idiopathic epilepsy, the cause of seizure activity is unknown or may be inherited. No matter what the cause is, though, it's important for you to know how to identify a seizure in your dog and understand your treatment options.
A seizure is also referred to as a convulsion or fit, which is a temporary involuntary disturbance of normal brain function that, in most cases, is accompanied by uncontrolled muscle activity.
The most common reason for seizures in dogs is idiopathic epilepsy, an inherited condition, whose exact cause is unknown. Other causes include brain tumors, brain trauma, infections, liver disease, liver failure, or a reaction to something toxic such as xylitol. Xylitol, a popular artificial sweetener, can cause dangerous drops in blood sugar and this can cause seizures.
Seizures can occur at any time of day or night, but they are most frequent at times of changing brain activity. This could include when a dog is excited, eating, falling asleep, or just waking up. Between seizures, most dogs appear to be completely normal.
Most seizures occur in three distinct phases. The seizure will typically move through all three phases, but there is no exact amount of time that each phase will last. Understand that each phase is different and once phase three is reached, the seizure is over.
- Pre-ictal (or aura) phase: A period of altered behavior in which your dog may seem nervous or try to hide or find its owner. The dog may appear restless and may whine or shake. This phase could last a few seconds or a few hours, as the dog likely senses that something is about to occur.
- Ictal phase: This is the seizure itself. It may last from a few seconds to about five minutes. During this phase, the dog may lose consciousness or just appear to be absent. If the dog is experiencing a full-blown seizure, known as grand mal, it may lose consciousness, fall over, and possibly move its body and legs erratically. It's possible the dog will also urinate, defecate, vomit, or salivate. If the seizure continues beyond five minutes, it's known as a prolonged seizure. This is considered to be an emergency, and you should seek the assistance of a medical professional immediately.
- Post-ictal phase: The time immediately following a seizure is usually accompanied by confusion, disorientation, restlessness, pacing, or even blindness. This is the phase when the brain recovers from what just happened.
Seizures are unexpected and in most cases can't be prevented, however some dogs will only seizure at times of extreme stress, and in these cases, the triggers can sometimes be avoided. Although they look traumatic, seizures aren't painful to the dog. The most harm to your dog may result from injuries it sustains during falls or flailing against objects in its vicinity during the seizure.
What to Do During a Seizure
Leave your dog alone during a seizure unless it's in a location where it could be injured. If you end up having to move the dog, gently move your dog to a safer location by pulling them by the hind legs or from around their chest. Although it will be easier to move them, avoid grabbing them at the front of their chest or shoulders to avoid accidental injury to you. It's OK to pet or comfort your dog during a seizure, but keep your hands away from its mouth—the seizure could cause the dog's jaws to clamp down on your hand.
It's vitally important not to put anything in your dog's mouth to brace against their teeth. Your dog won't choke on their own tongue during a grand mal seizure and trying to put something in their mouth to prevent them from doing so may cause even more harm.
It might be the last thing on your mind when your dog is having a seizure, but keep track of how long your dog's seizure lasts. Make note of any strange behavior they exhibited just prior to the seizure, such as strange vocalizations or activity. Similarly, keep track of your dog's behavior post-ictal and how long they remain in this post-ictal phase before returning to normal.
Although it's tempting to run straight to the vet, emergency veterinary care is only necessary if the dog's seizure lasts for more than five minutes or if two or more seizures happen in a 24-hour period. Prolonged seizures, or those lasting more than 5 minutes, can cause hyperthermia and sustained brain damage. More than 1 seizure in a 24 hour period is termed "cluster seizures" and can be indicative of an emergent disorder, such as a toxin ingestion or decompensation of a tumor within the body.
That being said, your veterinarian should be notified if your previously healthy dog has had a grand mal seizure. If your dog has a single, short seizure, make an appointment to have your dog checked out by your vet as soon as there's availability.
Because seizures in dogs may be caused by many different factors, your veterinarian will need to perform some diagnostic tests before she can determine the proper course of treatment. She'll start with your dog's complete medical history and may focus on any events involving head trauma and/or exposure to poisons or hallucinogenic substances.
Next, the vet will conduct a thorough physical exam, which often includes blood and urine tests and an electrocardiogram or ECG. The vet uses these tests to rule out medical issues with the dog's liver, kidneys, heart, electrolyte, and blood sugar levels. If your dog isn't taking a monthly heartworm preventive, she'll likely test your dog for heartworm as well.
If all test results are normal and don't indicate exposure to poison or trauma, your vet may conduct further tests such as a spinal fluid analysis or a CT (computed tomography) scan or MRI (magnetic resonance imaging). CT scans and MRIs are non-invasive diagnostic tools that produce images of the brain and other internal tissues.
If the seizures are occasional and occur less than once every four to six weeks, your vet might not be as concerned and may not recommend the more invasive or costly tests unless the seizures become more frequent, more severe, or both.
To best treat your dog's seizures, your vet will want to know about any seizure history. Keep track of your dog's seizure history. Write down the information, date it, and store it with your pet's medical records. Most vets will only begin treatment if your dog has had:
- Seizures more often than once every four to six weeks.
- Cluster seizures (multiple seizures in a 24 hour period).
- Grand mal seizures that are prolonged
The vet will likely treat your dog with an anticonvulsant medication such as phenobarbital or leviteracitam (Keppra). Once you start your dog on an anticonvulsant med, you must continue it for the rest of the dog's life. If it's discontinued, the dog is at greater risk for seizures. Speak with your vet about all your options and be clear on all instructions if you find you need to switch to another medication.
Canine Idiopathic Epilepsy. Missouri University Veterinary Health Center, 2020
Seizures in Dogs. Small Door Vet, 2020
Podell, M. et al. 2015 ACVIM Small Animal Consensus Statement On Seizure Management In Dogs. Journal Of Veterinary Internal Medicine, vol 30, no. 2, 2016, pp. 477-490. Wiley, doi:10.1111/jvim.13841