Seizures come in all shapes and sizes.
The big, bad grand mal seizure is a generalized, convulsive seizure with widespread, excessive, abnormal electrical activity occurring in both sides of the brain. Also known as tonic-clonic, this type of seizure is the one where a dog suddenly falls over with violent, jerking spasms affecting all four limbs, paddling, frothing at the mouth, possible loss of bladder and bowel control, and loss of consciousness.
If this happens, first, make sure you both stay safe. To keep your dog safe from injury, remove any items near them that are breakable or that may fall on them. If they are near stairs, try to stay below them on the steps — if you can safely do so — to prevent them from falling down further.
Avoid your dog’s mouth so you don’t get bitten. Your natural tendency may be to comfort your dog by hugging or stroking their head. But your dog is not aware of their surroundings during a seizure, and they are not in control of their movements either. Furthermore, in the minutes to hours after a seizure (a period called the postictal phase) your dog may remain disoriented or confused, which can sometimes be expressed as aggressive behavior. You need to be careful.
Try to time the seizure and keep a log. Timing the seizure is important because of a life-threatening condition called status epilepticus.
“Status epilepticus is an ongoing seizure that doesn’t self-resolve, typically considered more than five minutes,” says Dr. Peter Early, visiting clinical professor of neurology in the Department of Clinical Sciences.
If a dog is in status epilepticus for too long, they could die. There is so much intense, violent physical activity that the core body temperature rises to life-threatening levels. Status epilepticus requires emergency veterinary intervention with intravenous medication, usually a benzodiazepine like diazepam (Valium), to break the seizure.
Beyond the classic grand mal seizure described above, other generalized seizures include:
- Tonic (stiff, extended limbs that don’t move or jerk)
- Clonic (hyper-flexed, non-jerking limbs)
- Myoclonic (jerking limbs)
- Atonic (standing, staring and non-responsive)
Focal seizures, as opposed to generalized seizures, happen when the abnormal electrical activity is localized to just one spot in the brain. This can look like a lot of different things. For example, “fly-biting” is a classic one, where the dog looks like they are seeing and repeatedly snapping at flies. The “chewing gum fit” is where the jaw repeatedly clacks.
A focal seizure might just be repeated twitching of an eyelid, lip or ear. There is not necessarily a loss of consciousness. These types of seizures usually don’t require treatment. However, a focal seizure can segue into a generalized seizure, so be sure to keep a close watch on your dog until it passes.
Seizures can be caused by metabolic disorders like low blood sugar or low blood calcium, liver disease, liver shunts, kidney disease and others. These seizures are called reactive seizures. The brain is normal, and if the metabolic disorder can be corrected, the seizures go away.
Some drugs can cause seizures by lowering the seizure threshold in the brain. Discontinuing the drug resolves these reactive seizures.
Toxins can also cause seizures. This is part of the risk of things like dark chocolate, caffeine, the sugar substitute xylitol, anti-freeze, rat poison and liquor. Eliminating exposure to the toxin and giving treatment for the toxin resolves the seizures.
Additionally, seizures can be caused by abnormalities in the brain itself. Called structural seizures, they’re caused by things like tumors, head trauma, inflammatory diseases and infectious diseases, like rabies and canine distemper.
However, the most common cause of seizures is idiopathic epilepsy, which is a seizure condition of unknown origin. A diagnosis of idiopathic epilepsy is typically made after every other cause has been ruled out.
Idiopathic epilepsy usually starts between 6-months-old and 6-years-old. Dogs younger than 1-year-old are more likely to have a congenital defect, an intoxication or an infectious disease like canine distemper. Dogs that are over 6-years-old when they have their first seizure are more likely to have a metabolic disorder or a structural brain lesion, like a tumor or a stroke.
Breed predilection toward epilepsy is another clue your veterinarian uses during diagnosis. Schnauzers, Collies, Bassett Hounds, Cocker Spaniels, Labrador Retrievers and Golden Retrievers have higher rates of seizure conditions compared to other breeds.
If your dog is between 6-months-old and 6-years-old, and their tests are normal, most veterinarians agree antiepileptic drug therapy is not necessary after the first seizure.
There are exceptions, however, including:
- Cluster seizures (one or more seizures in a 24-hour period)
- Particularly violent seizures
- Seizures lasting 5 minutes or more
- Breed predisposition: German Shepherd Dog, Border Collie, Irish Setter, Golden Retriever, Siberian Husky, Keeshond and Saint Bernard (— all known to experience difficult seizures)
For all the other situations, your seizure log will help determine when it might be time to start anticonvulsant therapy, based on increasing length, frequency and severity of seizures.
You might wonder why you shouldn't just start your dog on anticonvulsants to prevent another seizure. But consider this: Your dog may never have another seizure. Or they may have a mild one once a year. We really don’t know until it plays out. And once an antiepileptic is started, it is generally necessary for life.
Similarly, if your dog is an epileptic who rarely has a seizure, then you are taxing their body with a medication that they really don’t need, and you are paying for it. In addition, well-managed epileptics on anticonvulsants may still have breakthrough seizures here and there. So, a seizure-free future is not a guarantee, even with long-term medication.
Keeping in mind the above reasons for not starting anticonvulsants right away, we should point out that the seizure itself is perhaps not completely benign. Some research studies discuss the fact that dogs appear to have abnormal MRI brain lesions in the aftermath of a seizure. These lesions are called postictal changes (PC) and are thought to be due to a combination of cellular damage, cellular stress and swelling. In humans, these lesions are known to reverse with time. The presumption is that this may also be true for dogs, but further study is needed.
“A general rule is to start antiepileptic drugs if there is more than one seizure a month,” Early says. Most veterinary professionals think that if a dog is seizing as much as once a month, it’s interfering too much with their quality of life and yours. Starting anticonvulsant therapy will likely be recommended in this case. You, however, should be the ultimate decider of when enough is enough and it’s time to treat.
Phenobarbitol, levetiracetam (Keppra), zonisamide and potassium bromide are all good first choices for treatment. There are several different anticonvulsants available for dogs. Zonisamide and levetiracetam have become popular because they work well with minimal side effects. Phenobarbital, potassium bromide and topiramate are other medications your veterinarian may discuss with you.
“Approximately 20% of dogs have refractory epilepsy and require more than one antiepileptic medication,” Early says. Some dogs may require more than one medication to manage their seizures. Levetiracetam is frequently used as a second medication. It is short-acting, which means it must be dosed three times a day. This can be challenging for dog owners. The extended-release formula, Keppra XR, with its twice-a-day dosing, is easier.
“There are challenges and frustrations with refractory epilepsy cases,” says Early. For example, what if your previously well-managed epileptic is having more and more breakthrough seizures? Unfortunately, some dogs will develop a tolerance to their anticonvulsant medication over time. In these cases, the liver continuously increases the rate at which it metabolizes the drug, making higher and higher doses necessary. And, of course, higher doses usually mean stronger side effects. These cases can be very challenging to manage.
Seizures in dogs can be frightening and hard to endure. Luckily, we have many tools to help diagnose and manage this tough condition. Always consult with your dog’s veterinarian to be sure that you're making the best decision for your unique dog and lifestyle.
Other therapies your veterinarian may recommend
Rectal diazepam or intranasal midazolam
Your veterinarian can dispense diazepam (Valium) for rectal administration during a seizure. This will be dispensed to you with a syringe and a rubber tube. Gently introduce the tip of the rubber tube about an inch into the rectum and dispense the medication — this will often shorten and lessen the severity of the seizure. Your veterinarian may also suggest intranasal midazolam, which is another benzodiazepine that can be applied inside your dog’s nostrils to control seizures at home.
Pulse Keppra therapy
If your dog is prone to cluster seizures while on an anticonvulsant, ask your veterinarian about keeping levetiracetam on hand. A few doses of this short-acting anticonvulsant can be given after a seizure to prevent a cluster.
Stimulating your dog’s vagal nerve may help lessen the duration and severity of a seizure. If you can safely do this, gently push on your dog’s eyes, with closed lids, for 10-60 seconds. This can be repeated every five minutes. If you recognize your dog’s early (pre-ictal) signs, you may even be able to stave off a seizure with this maneuver.
Traditional Chinese Veterinary Medicine (TCVM)
TCVM includes acupuncture and Chinese herbal remedies, and it can improve seizure control for dogs with refractory seizures even when on antiepileptic medication. Or it can help lower the dose of anticonvulsant medications. You will need to find a specialist trained in this art, however, as most general veterinary practitioners are not.
Purina Pro Plan Veterinary Diet NeuroCare (NC) is an option, especially if your dog has refractory seizures despite anticonvulsant medication. This diet contains medium chain triglycerides (MCTs), which are known to block one of the receptors in the brain that is responsible for seizures. Studies have shown a significant reduction in seizure activity when epileptic dogs are fed this diet.
This article has been reprinted with permission from the Cornell University College of Veterinary Medicine’s DogWatch newsletter, published by Belvoir Media Group. When you become a member of the Riney Canine Health Center, you will receive a free subscription to DogWatch.