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If you have ever had a dog that has had a seizure, you know how frightened and helpless this type of event can make you feel. Despite the intensity of such seizure events, dog owners with an affected pet can prepare themselves through education, training, and resources to effectively handle them when they arise.
Seizures, which, simply put, are uncontrolled electrical activity bursts in the brain, can be categorized into several different types and can also have numerous causes. In this article, we’ll break things down and learn about the different types of seizures in canines as well as their causes, signs, and treatment.
What Are Seizures?
There is a lot of medical terminology to become familiar with in the world of seizures. As mentioned, seizures are uncontrolled electrical activity bursts in the brain. Epilepsy is a medical condition where a dog has seizures that are due to a cause within the brain (intracranial cause). Cluster seizures refer to a phenomenon where there is more than one seizure in a 24-hour period. Status epilepticus is the name for very long-lasting seizures; they last longer than 15 minutes or might be a conglomeration of seizures that repeat over and over again without recovering consciousness in between.
Additional terminology helps describe these different periods, or phases, of a seizure. Each phase has unique terms and signs (several of which we’ll discuss in the next section) and includes the following:
- Aura or preictal phase: Short period just prior to the start of a seizure
- Ictus: The actual seizure itself, often brief and less than 2 minutes (unless exhibiting seizure clusters or status epilepticus)
- Postictal phase: Period of recovery, which can vary in length but is often less than 30 minutes
Seizures themselves can also be classified as generalized or focal (also known as partial). Generalized are the most common type of seizure in dogs and include grand mal seizures, which are considered “classic” seizures. In these types of seizures, these dogs lose consciousness in addition to other signs, which we’ll discuss in the next section. In contrast, focal/partial seizures occur only in a small, specific area of the brain, and while the subject of the seizure does not lose consciousness, they do have altered mentation.
What Are the Signs of Seizures?
The signs of a seizure (or seizures) will depend on a few factors, including at what phase of the seizure the dog is in, as well as the specific type of seizure that is occurring.
In the aura or preictal phase, the dog will often exhibit behavior changes that include becoming restless, hiding, or crying. In the ictal phase, the signs displayed will be determined by the classification of the seizure. For generalized seizures, which is the most common seizure in dogs, the dog will lose consciousness and one may see classic signs of a seizure such as:
- Stiffness
- Falling to the side
- Paddling of the limbs in the air
- Excessive salivation
- Involuntary vocalization
- Involuntary urination
- Involuntary defecation
For partial seizures, one may see signs specific to the local area of the brain that is being affected. Again, these dogs are conscious but do have altered mentation. There may be short bursts of sudden aggression or aimless running. Fly-biting, tail-chasing, and flank-sucking are sometimes caused by partial seizures.
In the postictal phase, the dog may have behavior changes such as disorientation or confusion as well as pacing, weakness, or blindness.
What Are the Causes of Seizures?
There is a long list of potential causes for seizures. Some of the most common causes include:
- Idiopathic epilepsy
- Symptomatic causes, which can include either intracranial causes or extracranial causes
Idiopathic epilepsy is the number one cause of seizures. In dogs, this occurs in the majority of cases. For idiopathic causes, the exact source of the seizure is unknown, but in these cases, there is no known underlying lesion in the brain or any other neurological signs.
Intracranial causes are due to primary central nervous system disease (diseases of the brain) and include numerous categories such as:
- Degenerative
- Anomalous
- Neoplastic (this typically occurs in older animals, but that may not always be the case. Here, neoplasia can cause seizures due to primary brain tumors, such as meningioma, or secondary metastasis of cancer from elsewhere that has spread to the brain)
- Infectious (this could be bacterial, fungal, viral, protozoal, or parasitic)
- Inflammatory
- Idiopathic (mostly starts to occur in dogs from 1–5 years old and is a diagnosis of exclusion)
- Trauma (this would be in dogs that have head trauma that results in unconsciousness; typically, in these cases, seizures start within 2 years of said event)
- Vascular
Extracranial causes are due to secondary effects on the central nervous system and include:
- Metabolic disease (such as low blood sugar or liver disease such as a liver shunt)
- Nutritional (one example is thiamine deficiency)
- Toxins (there are numerous examples, but some could include lead, moldy walnuts, mycotoxins, some types of human medications, etc.)
How Do I Care for a Dog with Seizures?
Testing
A veterinarian will likely have lots of questions and need a very detailed history alongside a physical and neurologic exam. To rule out some causes of seizures, baseline lab work, such as several different types of blood tests and urine tests, will be necessary. Coupled with the history and signalment as well as any exam findings, in many cases, further testing such as an MRI (magnetic resonance imaging) or CT (computed tomography), a CSF (cerebral spinal fluid) tap, or EEG (electroencephalography) may be indicated. Older animals may also be screened for cancer via thoracic radiographs and an abdominal ultrasound. There is also the potential for specialists such as a veterinary neurologist to become involved in the aforementioned further testing or for referral in some cases.
If further testing is not possible, a veterinarian may sometimes recommend the start of treatment even without an exact known cause or diagnosis. However, if a dog is less than 1 or greater than 5 years old, further testing is typically strongly recommended as this may change the treatment and, ultimately, prognosis. For example, in dogs that experience seizures due to having the most common type of brain tumor, a meningioma, the tumor can be removed surgically and have a good prognosis.
Treatment
Treatment of seizures is recommended earlier rather than later, as over time, untreated seizures can increase in intensity. Soon, the affected dog may need more medication than would have been needed before, and it can be more difficult to recover. The criteria used to determine whether a dog should start seizure medication can vary but is often based on how long or how often seizures are occurring. For example, some guidelines may say if there are more than two seizures in a 6-month period or if a seizure occurs within a week after sustained head trauma, that medication is justified; but such criteria can vary, and sometimes, even if you ask two different neurologists, you’ll get two different answers as to whether medication should be started!
Several antiepileptic medications exist, and the most common anti-seizure drugs try to make the brain cells less likely to fire. These medications may be able to be used by themselves or, sometimes, in conjunction (polypharmacy). It is important to note that even with treatment, complete resolution of seizures is not expected or likely. In addition, these medications can have negative side effects, including increased drinking, urinating, and eating, as well as lack of coordination, toxicity to the liver, sedation, or hyperexcitability. Relapses with seizures can be common, but most dogs will see some success on medications for seizures. If a dog is on seizure medication, it should not be stopped suddenly; the medication will need to be slowly tapered off, often over several weeks to months, and at the direction of a veterinarian.
Care
One way veterinarians often can monitor progress is by having the affected dog’s owner keep a seizure journal/calendar. This entails the owner recording many details about their dog’s seizures including the date and time, how long the seizure lasted, the severity, as well as what happened before, during, and after the seizure. In addition, video footage of the dog during these events can also be helpful. Together, a seizure calendar and video footage are helpful for monitoring purposes and can be used to confirm what is happening as well as to see if changes need to be made regarding the treatment plan.
Frequently Asked Questions
What’s the prognosis for my affected dog?
The overall prognosis for a dog with seizures will depend on both the cause of the seizure and the response to treatment. It’s important to have a conversation with your dog’s veterinarian for realistic expectations, as each individual case will be different. For example, a dog with idiopathic epilepsy that, with medication, only has one seizure every several months has a good prognosis, while a dog with status epilepticus that is not responding to multiple seizure medications would have a very poor prognosis.
Can seizures be hereditary?
While seizures due to trauma are not hereditary, dogs experiencing seizures due to congenital conditions or idiopathic epilepsy may be experiencing their seizures due to inherited factors and should not be bred. For example, some breeds that are predisposed to idiopathic epilepsy include Labrador Retrievers, Golden Retrievers, and German Shepherds.
Conclusion
Seizures in our furry friends can be a hard thing to witness and to have to deal with. Despite feeling powerless, there are things one can do to help their pup! One is keeping a seizure calendar as well as seeking early veterinary care when seizures are observed as the next step.
Featured Image Credit: antoniodiaz, Shutterstock
