Seizures are the result of episodes of involuntary electrical activity within the brain and can take many forms, ranging from loss of consciousness and leg paddling to subtle, intermittent changes in behavior. Many different diseases can cause seizures in dogs. Problems that originate outside of the brain, such as low blood sugar, hypothyroidism, severe liver and kidney disease, or certain poisons are sometimes to blame. On the other hand, infections, trauma, tumors, inflammation, and other disorders that are limited to the brain itself can all also disrupt normal brain function and bring about a seizure.
In some cases, even after a thorough health work up no underlying cause for a dog’s seizures can be found. If they become a reoccurring problem, veterinarians call the condition “idiopathic epilepsy.” The mechanism that causes certain animals to develop epilepsy is not fully understood, but genetics certainly plays a role. Breeds that are at a higher than average risk for developing the condition include schnauzers, basset hounds, collies, German shepherds, keeshonds, Belgian tervurens, beagles, Irish setters, Saint Bernards, poodles, wirehaired fox terriers, cocker spaniels, and Labrador and golden retrievers.
When many people think of a “typical” seizure they are picturing a generalized or grand mal seizure. During one of these episodes, an affected dog will fall down, usually paddle or intermittently stretch out its legs, may lose bladder and bowel control, and is completely unaware of its surroundings. But less dramatic types of seizures exist as well. These may be called partial, focal or petit mal seizures and develop when only a limited portion of a dog’s brain is affected by abnormal electrical activity. Dogs undergoing a focal seizure remain conscious and exhibit abnormal motions that are restricted to only a portion of their body (e.g. involuntary movement of a leg) or unusual behaviors, such as snapping at the air as if they are trying to catch an imaginary fly.
Because seizures can take so many forms, dog owners are often unsure whether or not their pets have actually had a seizure after a suspicious incident has occurred. True seizures have three distinct phases. The aura or prodromal phase occurs in the minutes before seizure activity begins. Dogs may act restless or behave in an odd manner, but this stage is subtle and often missed by owners. The ictal stage is the time during which a dog is actively seizing. The most important phase to watch for when trying to determine whether or not an episode was actually a seizure is the post-ictal stage. This is the period after the seizure has ended when dogs appear confused and cannot walk or behave normally. The post-ictal stage may last for only a few minutes or for several hours. Pets that have lost consciousness for reasons other than a seizure (e.g. fainting) generally do not act confused after they have recovered.
In some cases, seizures can be life threatening. Dogs should be taken to a veterinarian immediately if any of the following symptoms are noted:
- an individual seizure lasts longer than five minutes (not including the aura and post-ictal phase).
- seizures cluster together so that the dog does not have time to fully recover between episodes
- more than three seizures in a 24-hour period are observed
Permanent neurologic damage can occur if such severe episodes are not treated aggressively.
One of the most important things that a pet owner can do when faced with a dog that is having seizures is to write down the dates and times when the episodes occur, what they look like, how long they last, and if the dog seemed normal in between events. If at all possible, time seizures using a clock. To a worried pet owner, a seizure that actually lasts only 20 seconds may seem to drag on for many minutes. This information will be invaluable to the veterinarian when it comes to deciding what potential underlying causes are likely and how to proceed with treatment.
Before diagnosing a dog with idiopathic epilepsy, the veterinarian will try determine if any other disease might be present that could be causing the seizures. The doctor will start by performing a thorough physical and neurological exam, usually followed by blood work, a urinalysis, and a fecal exam. If infection or inflammation of the brain is a likely culprit, the veterinarian may want to obtain and analyze a sample of cerebrospinal fluid (CSF), or if signs are pointing towards a tumor or other lesion within the brain, he or she can recommend a CT scan or MRI. Once additional testing is unlikely to reveal an underlying cause for a dog’s seizures, a diagnosis of idiopathic epilepsy can be made.
Treatment and Prevention
Whenever possible, treatment is aimed at any potential causes for seizures that have been discovered during the diagnostic work-up. If the therapy is effective and no significant brain damage has occurred, the seizures should resolve. The situation is very different with a diagnosis of idiopathic epilepsy. This is a disease that can usually be managed but cannot be cured. If seizures are mild and infrequent, many veterinarians will take a “wait and see” approach before starting treatment, but if a dog’s health is at risk from the seizures themselves, many anticonvulsant medications are available that can help control them.
Two drugs that are commonly used are phenobarbital and potassium bromide. These medications, either alone or in combination, can reduce the frequency and severity of seizures to a safe and manageable level for many epileptic dogs even if the episodes are not completely eliminated. If control is still not adequate, other drugs are available, but they tend to be expensive and/or need to be given frequently throughout the day. For emergencies, many veterinarians will also provide owners with a dose of liquid diazepam in a needless syringe that can be squirted into the dog’s rectum to help stop a seizure that is lasting long enough to be dangerous to the animal. If such an emergency occurs, owners must contact their veterinarian immediately.
Dogs that are being treated for epilepsy require close monitoring. Pet owners should keep a seizure diary. By looking at changes in the frequency and severity of seizures over time, a veterinarian can determine whether a dog’s medications should be changed. Blood work needs to be checked on a regular basis to determine if drugs are being dosed correctly and not causing any damage to internal organs.
With appropriate treatment and monitoring and a dedicated owner, many epileptic dogs enjoy a long and full life. Medications can usually decrease seizure frequency and severity to the point where epilepsy does not significantly affect the dog’s, or the owner’s, quality of life.
Jennifer Coates, DVM graduated with honors from the Virginia-Maryland Regional College of Veterinary Medicine in 1999. In the years since, she has practiced veterinary medicine in Virginia, Wyoming, and Colorado and is the author of several short stories and books, including the Dictionary of Veterinary Terms, Vet-Speak Deciphered for the Non-Veterinarian. Dr. Coates lives in Fort Collins, Colorado with her husband, daughter, and a menagerie of pets.