Epilepsy In Dogs

What Is Epilepsy in Dogs?

Epilepsy is a common neurologic disorder affecting the brain and is defined by recurring seizures without a known cause. It is estimated to affect approximately 0.75% of dogs. 

A seizure is caused by excessive electrical activity in the cortex of the brain. In dogs with epilepsy, the brain will appear structurally normal, but have abnormal electric impulses. Epilepsy is a diagnosis of exclusion, meaning it is diagnosed only after all other possible causes have been ruled out. This is also called primary epilepsy or idiopathic.

The abnormal electrical impulses start in one area of the brain (“seizure focus”) and spread throughout it causing involuntary movements and a loss of consciousness. This surge in electrical activity in the brain can cause a seizure that appears as twitching, shaking, tremors, and convulsions. 

Types of Epilepsy in Dogs

Seizures (neurologic events) can be confused with fainting spells (cardiovascular events). Seizures can be categorized into three phases:

• Aura: This is the pre-seizure feeling, as if the dog can sense that a seizure is coming.  During this phase the dog may appear anxious, frightened, or attention seeking behavior. This behavior may be hard for the pet parent to recognize.

• Ictal: This is the seizure itself which typically lasts 1-2 minutes, but you should seek immediate medical attention if it lasts more than 5 minutes. 

• Post-ictal: The post-ictal disorientation is the hallmark of seizures. During this period, the dog will be disoriented and may even appear blind. This can last for only a few minutes or up to several hours. In contrast, fainting animals are normal within seconds of the episode with no post-episode disorientation.

Not all seizures look the same and knowing which type your dog is experiencing may help your veterinarian.

The main categories are:

• Generalized (Grand Mal) Seizures: This is the most common form of seizure in dogs. In this type of seizure, the dog collapses falling over to its side and becomes unconscious, the limbs are extended and stiff, and there are convulsions or violent shaking. The dog may urinate or defecate on itself, hold its breath, and/or have chewing motions and drooling. All epileptic seizures are grand mal, but not all grand mal seizures are epilepsy, as other causes of seizures can result in grand mal type seizures.

• Partial (Focal) Seizures: Also called partial motor seizures, this type of seizure appears as abnormal movements restricted to only one part of the body, such as the face or one leg. However, a partial seizure will frequently spread and result in a generalized seizure. The differentiation is important because partial seizures are acquired (meaning there is an underlying cause) and are not seen with primary epilepsy. The classic exam of a partial seizure is a “chewing gum” seizure where the pet is conscious but involuntarily appears to be making a chewing gum motion with its mouth.

• Complex Partial Seizures: Also called psychomotor or behavioral seizures, this subset of focal seizures looks more like an episode of abnormal behavior than a tremor or convulsion. The dog is conscious but appears to be acting differently (including hysteria or rage) or hallucinating. The classic example is called “fly-biting” seizures, where the dog appears to chase and bite at an imaginary fly. 

Symptoms of Epilepsy in Dogs

Clinical signs include:

• Stiffening of the body and legs

• Collapse and falling over to the side

• Chewing motion

• Drooling

• Paddling of the legs

• Urinating

• Defecating

• Vocalizing

• Violent shaking, trembling, and convulsing

Causes of Epilepsy in Dogs

Epilepsy is a diagnosis of exclusion, meaning all known causes of seizures must be ruled out before reaching a diagnosis of epilepsy. The first seizure in dogs with primary epilepsy is usually seen between the ages of 6 months and 5 years.

Epilepsy may be inherited in some dogs. Dog breeds known to have a genetic basis include:

• Beagle

• Dachshund

• German shepherd dog

• Keeshond

• Belgian Tervuren

Additionally, despite no known genetic link, certain dog breeds have a high incidence of epilepsy:

• Boxer

• Cocker spaniel

• Collie

• Golden retriever

• Irish setter

• Labrador retriever

• Miniature schnauzer

• Poodle

• Saint Bernard

• Siberian husky

• Wire fox terrier

How Veterinarians Diagnose Epilepsy in Dogs

The first step is to confirm that the dog did in fact have a seizure. It is extremely helpful if the pet parent can video the episode and keep a log of any evidence of aura, a description of the seizure, how long the event lasted, and the length of the post-ictal phase (the dog will be disoriented and may even appear blind for only a few minutes, or up to several hours).

Dogs who have a seizure for the first time should be seen immediately by a veterinarian.  A thorough history followed by physical examination and full neurologic examination will be done.  A complete blood count, serum blood chemistry, and urinalysis will likely be recommended for a baseline evaluation to help rule out other causes, as well as chest X-rays and an abdominal ultrasound. 

If the tests are negative, your veterinarian may be suspicious of epilepsy. Referral to a veterinary neurologist may be recommended, along with more advanced diagnostics such as bile acids, MRI, or cerebrospinal fluid (CSF) testing. If all tests are negative, epilepsy may be diagnosed. 

Treatment of Epilepsy in Dogs

Epilepsy is a life-long condition which cannot be cured, but it can be managed. In most cases it will require daily medications for life. The right anti-epileptic medication for your dog may depend on several factors and will be determined by your veterinarian. 

The four most prescribed medications include:

• levetiracetam (Keppra)

• phenobarbital

• potassium bromide

• zonisamide

A combination of anti-seizure medications is typically prescribed for better control, including the use of gabapentin (Neurontin) and pregabalin (Lyrica).

The goal of treatment is to decrease the number of seizures. Keep in mind it’s typically not possible to eliminate them completely. Control is achieved if the dog is having less than one seizure every 3 months.

The following includes EMERGENCY criteria. If your dog is experiencing any of these concerns, please take them to a veterinary emergency hospital immediately: 

• One seizure lasting more than 5 minutes

• Cluster seizures, which means one seizure rolls into another, causing repeated back-to-back seizures. This can be life-threatening.

• More than 3 seizures in a 24-hour period

Epileptic patients can have emergency criteria at the beginning of their diagnosis and treatment, or can have breakthrough events while being treated. It is important to understand that seizures increase the likelihood of them happening more, so if your dog’s seizures are not well controlled, please follow up with your veterinarian.   

Recovery and Management of Epilepsy in Dogs

Seeing your dog have a seizure is scary and can be very emotionally challenging—but you are not alone Many pet parents experience the same stress of not knowing what the future may hold for their dog’s health.

Appropriate medications may allow most dogs with epilepsy to resume normal lives. Sticking to your dog’s medication schedule—by making sure medications are given on time and doses are not missed—is crucial to successfully managing epilepsy—along with your veterinarian.

Periodic follow-up appointments may be necessary depending on the specific medication your dog has been prescribed. Some dogs may require medication adjustments over time if breakthrough seizures occur.