Dog Seizure Signs
By Dr. Lisa Lipitz, VMD, DACVIM (Neurology)
Seizures are the most commonly reported neurological problem in dogs. For most dog owners, witnessing a beloved pet have a seizure is a scary experience. Epilepsy is a chronic condition characterized by recurring seizures; these often occur unpredictably which presents a further challenge for owners. The prevalence of canine epilepsy is estimated to be between 0.5-5-7 percent. This means that as many as 1 in 20 dogs may experience a seizure in their lifetime. Here are signs that indicate that your dog may be experiencing a seizure and what to do in that situation.
How would you define a dog seizure?
A seizure is a transient manifestation of signs due to abnormal, excessive activity of neurons in the brain. Seizures always indicate dysfunction in the forebrain (the cerebral cortex). The cerebral cortex is made up of a large number of neurons that communicate with each other via chemical messengers called neurotransmitters. Neurotransmitters may excite or inhibit other neurons. Normal neuronal activity represents a healthy balance between excitatory and inhibitory influences. Seizures occur when there is imbalance in these mechanisms, favoring sudden excitation and increased firing of neurons.
What causes seizures in dogs?
Excessive excitation in the brain resulting in a seizure can happen due to the following causes:
Reactive seizures occur secondary to metabolic disease or toxin exposure (that affect a dog’s otherwise healthy brain). Diagnosis is made via tests like bloodwork and history information.
Symptomatic seizures result from structural brain disease and include conditions like tumors, strokes, malformations, inflammation, or infections in the brain. These are diagnosed via imaging of the brain (usually MRI examination) and sometimes spinal fluid analysis.
Unknown/Idiopathic seizures do not have an identifiable cause. This category encompasses genetic epilepsy, which is the most common cause of seizures in dogs. This diagnosis is made via exclusion of the above two categories, as all diagnostic tests return normally.
The most practical way to group causes of seizures is by age of onset. In puppies younger than six months, brain infections, toxin exposure, metabolic conditions like liver shunts, and congenital brain malformations are most common. In dogs between six months and five years, idiopathic (genetic) epilepsy is most common; in at least 25 dog breeds, a heritable basis for epilepsy has been documented thus far. In animals older than five years, structural brain disease, specifically tumors and strokes, are most common. However, exceptions to these ‘rules of thumb’ occur; the only way to determine the cause of a seizure is via a diagnostic workup with your veterinarian.
What are the symptoms of seizures?
There are three stages of a seizure in dogs:
Aura: Minutes before the actual seizure, a period of altered behavior may occur called the aura. This is not always recognizable, but many owners report their dogs may hide, appear anxious, attention seek, or whine just prior to a seizure.
Ictus: The actual seizure is called the ictus. It usually lasts seconds to one to two minutes and is self-limiting, but longer seizures can occur. Seizures can have a variable appearance (as described below).
Postictal phase: After the seizure, many dogs exhibit a postictal phase characterized by disorientation. This may last minutes to hours. The most commonly reported signs are behavior changes, prolonged sleepiness, confusion, transient blindness, and eating voraciously.
Are there different types of seizures?
Yes, seizures can take on many forms. Which area and how much of the cerebral cortex is abnormally firing will determine how a seizure looks clinically.
A generalized tonic-clonic seizure (also referred to as a grand mal seizure) is the most common form and the most easily recognizable. Both cerebral hemispheres are activated simultaneously. It is characterized by falling to the side, loss of consciousness, and rhythmic contraction of muscles (paddling, jerking of limbs, chewing jaw movements). Some dogs also salivate, urinate, and defecate.
A focal seizure (also referred to as a partial seizure) can be more difficult to recognize. It results from a group of neurons firing in one part of the cerebrum, with limited spread to other areas. There are two types of focal seizures:
Simple (focal motor) seizures result from firing of neurons in the motor area of a cerebral hemisphere and usually manifest as involuntary limb jerking or repetitive facial muscle movements. Consciousness may or may not be impaired.
Complex partial (psychomotor) seizures are the most challenging for pet owners and veterinarians to recognize because they manifest as a behavioral abnormality. These originate from the limbic system or temporal lobe of the cerebrum. Consciousness is usually impaired. Examples include motionless staring, aggression, and hallucinatory behavior such as fly biting.
What should you do if your dog is having a seizure?
The most important thing is to ensure your dog does not fall or become injured while convulsing; try to keep your dog on the floor and away from stairs for their safety. Never put your fingers in a dog’s mouth during a seizure, as you could accidentally be bitten. Try to remain calm. Keep track of how long the seizure lasts and what you are witnessing. If your dog has not had a seizure before, taking a video of the event to show your veterinarian can be very helpful. During the postictal stage, observe and approach your dog slowly until he or she recovers and is back to normal behaviorally.
At what point should I take my dog to the vet if my dog is having a seizure?
Isolated seizures are rarely life-threatening and are usually self-limiting. If your dog has a first-time seizure, schedule an appointment with your veterinarian to determine the cause and discuss treatment options. If your dog has a pre-existing seizure disorder, such as idiopathic epilepsy, then he or she may already be taking daily anticonvulsant medication; in this case, notify your veterinarian when a seizure occurs to see if adjustments to your dog’s treatment plan are recommended.
Exceptions which are considered true emergencies include:
Cluster seizures: This is when two or more seizures occur within a 24-hour time period.
Status epilepticus: This refers to continuous seizure activity lasting longer than five minutes.
In these instances, a seizure may not be self-limiting without veterinary intervention which is life threatening; seek urgent care at an emergency veterinary hospital. Treatment involves intravenous valium to stop an active seizure, often followed by injections of long-acting anticonvulsant medications (such as phenobarbital and keppra) to prevent additional seizures from occurring.
What are some misconceptions people have about dog seizures?
Many people may not realize that a first-time seizure is often the most common sign of structural brain disease in older dogs. A seizure can be the sentinel that a growing brain tumor is present. Therefore, a new seizure disorder in an older dog almost always warrants a diagnostic workup.
Nearly three out of four of owners report a trigger for their dog’s seizures. These include stressful situations, barometric weather pressure changes, lunar phase, and sleep disturbances. Environmental triggers in canine idiopathic epilepsy have not been studied or proven to occur, but they are often noted by caregivers. It is a misconception that triggers can cause a seizure in dogs that do not have idiopathic epilepsy. A trigger is something that may make seizures more likely in dogs genetically prone to epilepsy.
Though it is a hot topic of discussion, there is no proven association between food intolerance causing epilepsy in dogs. No studies on raw food or grain free diets have been performed in epileptic dogs and there are known health risks to feeding these diets so they are not recommended.
Post-ictal, home rescue remedies are another source of misconceptions. Some online sites advocate administering herbal remedies like Bach flower or feeding vanilla ice cream to dogs following a seizure; while the potential for adverse effects is low, there is no evidence that these practices are effective. If your dog has a severe seizure disorder, your veterinarian may dispense valium rectal suppositories for use to stop an active seizure and expedite post-ictal recovery time.
What is your dog likely to feel during a seizure?
Even though seizures often look quite terrifying, in reality dogs are usually unconscious and therefore unaware that the seizure is occurring. Seizures are not painful events. Therefore, it is likely harder for pet owners to observe than for dogs themselves to experience.