Seizures are not uncommon in dogs. Up to one out of every 20 dogs will experience a seizure during its lifetime. Seizures, which are sometimes called convulsions or fits, are caused by a sudden, temporary disruption in normal brain function. This disruption can lead to a wide range of symptoms, including odd behaviors, muscle spasms or rigidity, disorientation, loss of consciousness, weakness, or loss of bowel and bladder control.
While dogs of any age and breed can experience a seizure, this neurological disorder strikes certain breeds more often, including German shepherds, beagles, Labrador retrievers, miniature schnauzers, and collies. And although there are many causes of seizures, the most common in dogs is idiopathic epilepsy, also called genetic or inherited epilepsy. Idiopathic epilepsy is most often diagnosed in dogs between the ages of six months and six years of age, but it is not unheard of for older, or even senior, dogs to receive this diagnosis. In fact, up to 45 percent of senior dogs with new-onset seizures will be diagnosed with epilepsy.
However, when an older dog experiences a seizure for the first time, there is a good chance that the cause is a structural problem in the brain, typically a stroke or a tumor. Even if this is the case, there is often treatment available that can help extend your pet's life, or at least keep it comfortable during its remaining time. Should your older dog have a seizure for the first time, it's important to talk to your veterinarian as soon as possible.
What Are Seizures?
A seizure is an uncontrolled electrical disturbance that occurs in the brain. This abnormal electrical activity then causes the dog to lose control of all or certain parts of its body, resulting in a variety of symptoms that can display as strange behaviors, abnormal movements, or loss of consciousness, depending on the type of seizure.
Seizures can come on very suddenly and vary in degree of severity and length, but they are all a result of something improperly working in the brain.
The typical seizure has three phases:
- In the pre-ictal, or aura phase, the dog has behavioral changes, such as whining, restlessness, hiding, or pacing. It may drool or tremble. This phase can last minutes to hours.
- The ictal phase is the main phase of the seizure. The dog will experience a wide range of signs during this phase, which can last seconds to minutes. Your dog might have jerking limbs, abnormal movements, strange behaviors, or looked dazed during this phase. Many dogs lose consciousness and fall down, and some lose control of their bowels and bladder.
- The final phase is post-ictal or post-seizure. During this time, the dog might be confused, restless, or disoriented. It might drool, pace, or even show signs of temporary blindness. This phase can last minutes to hours.
There are also different types of seizures.
Grand Mal Seizure
The most common type of seizure experienced by dogs, the grand mal seizure is obvious when it happens. Both sides of the dog's brain are affected during this type of seizure, which causes the dog to collapse, lose consciousness, experience jerking or rigid limbs, make strange facial movements such as grimacing or chewing motions, and possibly urinate or defecate.
The simple seizure, also called a focal motor seizure, only strikes one part of the brain. This is a more subtle seizure than a grand mal. The dog might make strange movements, such as chewing or moving the head oddly. It might have one or more jerking limbs. In this type of seizure, dogs do not always collapse or lose consciousness.
Complex Partial Seizure
Also called a psychomotor seizure, this seizure is marked by unusual behaviors. Your dog might sit and stare into space, suddenly become inappropriately aggressive, or carry out strange behaviors, such as snapping at the air. Generally, the dog seems to be hallucinating or "out of it" during these seizures, but does not usually collapse or lose full consciousness.
Symptoms of Seizures in Old Dogs
Young or old, dogs show a wide range of symptoms during a seizure, depending on the type of seizure, the seizure's cause, and the severity of the attack. The following are some of the possible symptoms your dog can experience during a seizure.
Some seizures are mild and won't affect your dog's entire body, while others completely, but temporarily, debilitate your dog. Sometimes a seizure manifests with odd behaviors such as staring off into space, biting at the air, or appearing lost or confused. In other seizures, a dog will fall over, lose consciousness, paddle its legs, twitch, vocalize, salivate, urinate, defecate, and arch its back. Other signs of a seizure can include excessive licking of the lips and chewing, despite not having any food in its mouth, or just being unable to use one side of its body or a leg.
It can be very frightening to observe your dog having a seizure. Do not attempt to put your hands into your dog's mouth during the seizure; it is not true that it can "swallow its tongue." Gently lower your dog to the floor and move away any objects that the dog might bang into during the seizure. Remain close by and calm until your dog recovers.
Causes of Seizures
Seizures can be caused by a number of things in a dog of any age, however, to a certain extent the age of the dog can narrow down the likeliest causes.
When puppies have seizures, the underlying cause is most often an infection, congenital brain abnormality, exposure to a toxin, or a metabolic problem. In dogs that are between the ages of six months and six years, epilepsy is the likeliest explanation. In older dogs, a new onset of seizures is often due to a tumor or a stroke. However, there are exceptions to all of these generalities and in many cases, the definite cause is never determined, in which case the dog is diagnosed with idiopathic epilepsy.
- Brain tumors: This cause of seizures is more common in old dogs in general and certain breeds in particular. Breeds that are more prone to developing brain tumors include boxers, bulldogs, Boston terriers, collies, Great Danes, greyhounds, and dachshunds. Overall, brain tumors are more common in dogs over the age of five.
- Overheating: Any dog, especially those that are overweight, elderly, or have short muzzles are prone to overheating if they are exposed to high temperatures. If a dog gets too hot, seizures can occur.
- Toxins: Any dog can consume something it shouldn't eat, and some chemicals or medications can cause seizures.
- Epilepsy: The most common cause of seizures in dogs overall is epilepsy. Although it's most often diagnosed in younger dogs, it is not that uncommon for a dog that is six years of age or older to develop epilepsy and begin having seizures.
- Metabolic disorders: Metabolic or endocrine disorders, including severe kidney or liver disease, hormonal disorders, electrolyte imbalance, and abnormal levels of blood sugar can all cause seizures. While these are all health issues that can strike any dog, senior dogs are at higher risk of developing severe kidney disease, liver disease, or diabetes.
- Traumatic brain injury: Dogs that suffer traumatic brain injuries, often due to a fall or being struck by a car, can develop seizures.
- Strokes: Senior dogs or dogs with high blood pressure, which are most often older dogs, are likelier to suffer a stroke which can then result in seizures.
Diagnosing Seizures in Old Dogs
Your veterinarian will first perform a full physical examination of your dog, as well as ask you about the symptoms displayed during the seizure. Usually, the vet will order blood tests and a urinalysis to determine or rule out various underlying causes of the seizure, such as metabolic disorders or infections. Often, especially with older dogs, the vet will order a CT scan or MRI of the dog's brain to look for signs of stroke or tumors. Sometimes, an EKG will also be ordered, which shows the workings of the dog's heart. X-rays of the dog's chest or ultrasounds of its abdomen to look for tumors, signs of infection, or structural abnormalities may be ordered as well.
It can take quite a few tests and a lot of time to determine what caused your dog's seizure.
Depending on the cause of the seizures, treatment protocols will vary. If the dog has an underlying condition, such as a metabolic disorder, cancer, or kidney disease, then treating that disorder should help reduce the risk of more seizures. Often, when no underlying cause is found and the dog is diagnosed with epilepsy, the vet will recommend no treatment at all unless your pet is having frequent or severe seizures.
If your dog has epilepsy and is experiencing seizures more often than once a month, or is having severe grand mal seizures, then your vet might prescribe an anti-seizure medication. Phenobarbital and potassium bromide are two of the most common drugs used for this purpose, although there are newer medications, including zonisamide and levetiracetam, which are becoming more commonly prescribed. Some dogs that do not respond well to one drug might require a combination of two or more medications to keep their seizures under control.
As a general rule, once a dog is started on anti-seizure medications, it must continue to take them for the duration of its life, as stopping the drug can sometimes trigger more seizures.
Prognosis for Old Dogs with Seizures
Your dog's prognosis depends greatly on the cause of the seizures. If cancer or a stroke is the underlying cause, or if your senior dog has advanced kidney or liver disease, then the prognosis is generally fairly poor. However, an otherwise healthy dog that merely has occasional seizures due to epilepsy can usually do very well on medications. It's important to follow your veterinarian's guidelines closely, however, and bring your dog in for regular examinations.
How to Prevent Seizures
Often, you cannot prevent seizures in an older dog, as they are due to unpredictable causes such as tumors, strokes, or underlying diseases that are more common in senior pets. However, you can help ward off the possibility of seizures by treating any known chronic or acute illnesses or conditions, and by bringing your pet to the veterinarian for regular checkups, recommended tests, and preventative treatments.
Dog Seizure Signs. Metropolitan Veterinary Associates.
Seizure Disorder in Dogs. Mar Vista Animal Medical Center.
Seizures in Dogs. VCA Animal Hospitals.