Understanding Seizures in Dogs and Canine Epilepsy

1. Introduction

Your usually lively dog suddenly seems unsteady and confused, then flops to the floor. They begin to twitch, drool, and move their legs as if treading water. Your dog is likely having a seizure, and understanding why can help you respond. Recurrent seizures may indicate epilepsy, a seizure disorder caused by abnormal, uncontrolled electrical bursts in the brain. Seizures can range from mild twitching to full-body shaking, lasting anywhere from seconds to minutes. While some seizures are medical emergencies, prompt veterinary attention and appropriate care can help many dogs lead normal lives. Sometimes, what appears to be a seizure could actually be muscle tremors, shivering, or even dreaming, which don’t affect a dog’s awareness. If possible, record your dog’s episode to assist your veterinarian with diagnosis and treatment.

Seizures in dogs can be a very emotional experience for both a pet owner and the pet itself. It is important for pet owners to be aware of what seizures look like and what to do if their pet experiences a seizure, regardless of its cause. A seizure can manifest as a series of bodily tremors and also as a complete unconscious episode in which the dog may lose control of his or her bladder or bowels. Fortunately, not all seizures lead to unconsciousness, but this can still be a very frightening experience for a pet owner to watch. Seizures are events that can be indicative of underlying pathology in many organ systems. The diagnosis of an "idiopathic" seizure does not necessarily mean the pet has epilepsy. Rather, this means that symptoms are indicative of seizures, but a physical reason cannot be detected. A diagnosis of grand mal or tonic-clonic seizure explains that coordination issues and proprioception are severely lacking in the dog's system during and after the attack. A diagnosis of a petit mal or absence seizure means symptoms are not as severe. Feelings of confusion, hallucinations, or decreased awareness may also explain this period of unconscious episodes. As progressive seizures have no bearing on multiple hits to the physical body, the behavior of dogs will often return to normal after an episode. Seizure disorders, as well as epilepsy, have a prevalence ranging from 0.5 to 5.7 percent of instances within the general dog population. More research and education are needed within this field to increase further awareness, information, and understanding of the issue of seizures in dogs.

2. Causes of Seizures in Dogs

While the first impression for many pet parents is that a seizure in their beloved companion is a result of a disorder such as epilepsy, in fact, there are a large number of potential causes behind seizures. Genetic causes that can lead to seizures also include other types of inherited neurologic diseases. Metabolic issues, including poor blood sugar control, poor oxygen supply, poor blood flow, and an imbalance of natural electrolytes in the body, have been shown to contribute to an epileptic state. Toxic causes include your pet’s exposure to poisons often found in the household. This can be as innocent as a pet parent giving their pets medications or as sinister as an accidental or intended poisoning through things like pesticides or suspiciously open medication bottles. Structural causes are a result of changes that occur in the brain that affect the way the neurons within the brain function. Structural changes can be a consequence of abnormal development, inflammation, nutritional defects, degenerative diseases, or the presence of tumors, of which there are several types that are documented to cause seizures. It is important to note that developing a seizure can be influenced by an individual pet’s genetic makeup. For example, certain dog breeds such as the Beagle, Belgian Tervuren, Bracco Italiano, Staffordshire Bull Terrier, and Vizsla have a statistically increased chance of developing genetic or idiopathic epilepsy. Puppies less than six months of age have the highest incidence of seizure activity, but dogs of any age can be afflicted. Outdoor pets are also at a higher risk of exposure to toxins and can develop seizures as a result. Some epilepsies, such as encephalitis, have been associated with infectious causes. Bacterial, viral, and parasitic components have all been studied and are reported to either cause or contribute to this disease and resulting seizures in dogs. Another difficulty with seizures is that diagnosing or determining the cause of the seizures can often be quite time-consuming, invasive, and require multiple tests to be run.

Schnauzers - Basset Hounds - Collies- German Shepherds-Border Collies- Australian Shepherds- Keeshonden- Belgian Tervurens- Beagles- Bernese Mountain Dogs- Irish Setters- Saint Bernards- Poodles- Wire Fox Terriers- Cocker Spaniels- Labrador Retrievers- Golden Retrievers

3. Types of Seizures in Dogs

There are several classifications for seizures and many causes, but the primary differences in seizures are made by where in the brain they start and if they impact the entire brain. The first set of seizures begins at the back of the brain, where if the dog is having a seizure, it will lose consciousness. These are considered general seizures in which all parts and areas of the brain are involved. The person or dog falls to the floor, all muscles in their body contract, and they paddle and shake. There are many types of general seizures in people, and the same holds true for dogs. General seizures are further subdivided into many types, but since the dog has lost consciousness, there are no behavioral differences between types of general seizures; they all involve loss of consciousness. This is classified as a grand mal seizure.

The second type of seizures is classified by where in the brain they start and if or how much awareness the dog has. Behaviors can be almost any sudden change, so lots of blinking, head movement, or body twitching might indicate that a person or a dog is having a seizure. These are considered focal seizures since they only involve one area in the brain. If there is no obvious behavior change, we used to call these partial seizures. If some behavior change is noted, but the dog is still aware, we call these focal aware seizures or simple partial seizures. There is no loss of consciousness for these dogs. If the dog does lose awareness, we call these focal unaware seizures or complex partial seizures.

3.1. Generalized Seizures

A generalized seizure affects all areas (lobes) of the brain. There are various types of generalized seizures, and each has its own set of symptoms. During a seizure, your dog will lose consciousness and have a sudden and unpredictable onset of various muscle movements (shaking, trembling, or twitching). Your dog may also alternate between muscle rigidity (stiffening) and muscle jerking or spasm. There may or may not be vocalization, and your pet may be unaware of its surroundings. They lose their ability to see, feel, and remain unconscious (they ignore you and do not react to their environment). The severity of the muscle movements and seizure activity can range from mild to severe, and generalized seizures often last from seconds to several minutes (but can last up to 24 hours). The return to a normal state of consciousness may be gradual, and your pet may seem dazed, confused, and disoriented for minutes to hours following a seizure. Different Types of Generalized Seizures: 1. Tonic-clonic seizures (classic grand mal seizures): This type of seizure typically involves loss of consciousness, and the animal falls on its side. They show stiffening and jerking (convulsive) movements of all four limbs, often with loss of involuntary movements such as chewing, drooling, urination, and defecation. 2. Absence seizures (also known as petit mal seizures): They are brief, usually lasting only seconds, involving an altered level of consciousness. Your pet may show mild staring, lip smacking, a blank gaze, and be unaware of its surroundings. 3. Myoclonic seizures: These manifest as short, sudden single jerking movements (myoclonic twitches), or they can be a cluster of these sudden twitches. This type of seizure can be subtle or more severe and involve a larger portion of the body. They are often seen with other types of seizures. Generalized seizures can be triggered by factors such as an underlying primary brain tumor or secondary damage from scar tissue following inflammation or infections in the brain. Certain weaknesses in the blood-brain barrier can also contribute to spontaneous seizure activity in some breeds of dogs. Conducting a physical examination and performing a thorough neurological examination, blood work, cerebrospinal fluid tap, CT/MRI scan, and electroencephalogram study are important tools that can help diagnose generalized seizures in your pet. Brain imaging and other diagnostic tests can also be instrumental in identifying the primary cause of seizures and ruling out other disorders. Management of dog seizures due to idiopathic epilepsy also includes weight loss requirements for overweight dogs, recommended limited exposure to known triggers such as high excitement where possible, and enhancing diet and good care to minimize the risk of healthy seizure threshold decline related to systemic illness. Treating generalized seizures may involve a combination of anti-epileptic medications alone or a combination of anti-epileptic medications and specific medications for cluster breakthrough seizures. Antiepileptic drugs will not prevent seizures, nor will they reduce a healthy seizure threshold. Brain tumors are potentially curable through surgery or radiation. The use of steroids or anti-inflammatories, and antiviral or antifungal medications depends on whether they are caused by an infectious disease of the central nervous system.

3.2. Focal Seizures

Focal seizures originate in a diffuse way within restricted areas of the brain. The signs and symptoms associated with focal seizures are highly dependent on the area of the brain that is affected. In some cases, the manifestation of a focal seizure may be quite subtle, causing a small twitch of a single muscle group or an unusual, isolated bout of repetitive behavior. Other focal seizures may be significantly more obvious, causing symptoms such as limping, head turning, unusual facial movements, fly biting, biting at invisible objects, or other bizarre behaviors. Different subtypes of focal seizures are often classified through the assessment of a dog's level of consciousness at the time of the seizure. In this way, focal seizures may be further classified as simple partial seizures, during which dogs remain completely alert, or complex partial seizures, during which an altered state of awareness may occur.

Identifying focal seizures in affected animals can be challenging, particularly when the associated symptoms are subtle, brief, and/or atypical. Reported causes of focal seizures in dogs are highly dependent on the area of the brain responsible for the abnormal electrical activity. In some cases, a focal seizure may occur randomly after a specific trigger is encountered. These triggers may be unique to individual patients and may include stress, excitement, sleep deprivation, bright light, or hormonal fluctuations. Treatment of focal seizures may require a more cautious approach than that used in canine patients diagnosed with idiopathic generalized epilepsy. The specific treatment strategy recommended for this type of patient is often highly variable and ultimately pursues the goal of reducing seizure frequency and increasing the dog's level of safety, but not at the expense of negatively impacting the animal's quality of life. Thorough examination by a qualified veterinarian is necessary for appropriate management of focal seizures.

4. Diagnosis and Treatment of Canine Epilepsy

The first step in understanding a patient’s epilepsy is to conduct a thorough veterinary evaluation to determine the origin, type, and severity of the seizure activity. This evaluation should include a comprehensive medical history and a thorough neurological examination. In order to confirm a diagnosis of epilepsy, veterinarians utilize multiple diagnostic tools, including blood tests to rule out other potential causes of seizures, imaging to identify structural lesions within the brain, and electroencephalograms to visualize seizure activity. Once a definitive diagnosis of epilepsy has been established, veterinarians work with pet owners to develop the most appropriate treatment plan for the individual patient.
There are two primary classes of medications used to treat canine epilepsy: anticonvulsants and adjuvant therapies. The purpose of an anticonvulsant is to reduce the frequency and severity of seizure activity, while adjuvant therapies are medications that help prevent side effects. The type and combination of medications used, as well as the decision to monitor the patient while taking a specific medication, are determined on a case-by-case basis. In addition to drug therapy, veterinarians may recommend further monitoring of the patient for the detection of any potential side effects and to determine the effectiveness of the current medication regimen. Some potential side effects involved with the use of anticonvulsants are increased frequency of seizures, sedation, incoordination, increased appetite or weight gain, excessive hunger or thirst, liver disease, and allergic reaction. Once a patient has been seizure-free for a period of time, medications can potentially be tapered off to determine if the patient can remain seizure-free. If seizures return, then full doses of anti-seizure medications may need to be restarted and can include another type of the anti-seizure medication that the patient has not already tried previously. In addition to anticonvulsants, adjuvant therapies may also be recommended; these are medications that minimize the side effects of long-term use of anticonvulsants or can be used in conjunction with anticonvulsants to help control seizure activity. There is also an injectable or rectal suppository form of diazepam that may be recommended to use at home by owners at the time a seizure is occurring or if one prolonged seizure continues. Once the patient is stable on the anti-seizure medications, the injectable or rectal suppository form of diazepam may be able to be discontinued for long-term use unless seizures return. It should be kept in mind that, while anti-seizure medications will not cure canine epilepsy, they can help to manage, control, and potentially decrease the frequency of seizure activity. Anti-seizure medications, however, may also require concurrent administration of periodic blood tests in order to monitor possible long-term side effects, depending on the medications chosen for an individual canine patient. Long-term monitoring of dogs for possible adverse drug effects, again mainly depending on the specific anti-seizure medications chosen, may or may not be necessary.

5. Managing Seizures in Dogs

Owners play an influential role in the management of their dogs with seizures. They are best positioned to recognize both subtle and more obvious changes in behavior that can precede the occurrence of a seizure. Prompt recognition leads to safer management of the dog during the event. Managing dogs during a seizure consists of removing objects or animals that could harm the seizing dog and providing a soft surface of protection around the dog. Once the seizure is over, many dogs, especially if new to seizures, should be taken to a veterinary hospital for examination. In the long term, there are multiple management strategies and interventions, both pharmaceutical and non-pharmaceutical, that can help to prevent or reduce the severity and frequency of seizures. Not all dogs necessarily benefit from treatment, and in some cases, the potential adverse effects of treatment can be a concern.

There are numerous pharmaceutical options that can be used to limit the frequency and severity of seizures in the dog. These drugs either control the excessive signaling of neurons within the brain or provide a neuroprotective effect on the neurons to lessen or prevent any secondary effects of seizures. While there can be a large dose range for each drug, and the two drugs may also be used together, in general, the starting point is to begin with a single drug as well as the lowest amount possible. Combination therapy can be started at this early stage in some cases, such as cases of prolonged or severe seizures. Lifestyle can also affect seizures. Obesity is a risk factor for idiopathic epilepsy, so attention to weight management and diet in general is beneficial. A consistent schedule and routine will help too, as stress and anxiety can cause seizures or reduce the threshold level, meaning an epileptic dog is more likely to have a seizure. Stress reduction for dogs can be achieved through exercise, maintaining the dog’s existing social structure, using adaptation modification to teach a dog to behave in a manner that is desired, and using calming aids or drugs if necessary.

5.1. Medication and Treatment Options

Canine epilepsy is managed medically with anticonvulsant medication. Phenobarbital is an older drug that is still widely used today. It works at the level of the sodium and chloride ion channels. Bromide is a drug that is especially useful in animals with severe, life-threatening seizures. Since the two drugs are metabolized differently and work at different levels in the brain, combining them often works synergistically and can control the seizures much better than one drug alone. Zonisamide is a newer anticonvulsant medication and, while more expensive, can also effectively reduce the number of seizures. Potassium bromide and zonisamide work at the level of sodium and calcium channels. Levetiracetam is new to veterinary medicine and is not metabolized in the liver. It works at the level of synaptic vesicle protein and effectively reduces seizure activity in the brain. Many caregivers try alternative treatment options, such as herbal remedies.

It is very important to tailor the treatment plan to the individual patient and not merely treat the seizure. Any seizure can be difficult to watch, but before opting for a new medication or treatment plan, it is important to consider a number of important points: 1. The seizure may be part of an illness that affects other parts of the body, not just the brain. 2. While all medications have side effects, not all dogs will experience them, and the benefit of an anticonvulsant often outweighs the risk of a potential side effect. 3. All medications take time to reach a therapeutic level in the bloodstream, so medication should be given as prescribed. Compliance is key in seizure management. Alternative modes of therapy, such as cannabis and herbal remedies, can also be considered. Herbal remedies may sedate the animal and may be useful for a dog with infrequent seizures. Silymarin is commonly used in dogs with seizures who receive phenobarbital or zonisamide since these drugs are metabolized by the liver. Many families also add dietary supplements or other treatment options to their pets' seizure protocols. Always read the label when giving your dog over-the-counter medication and contact your veterinarian with any questions. Monitoring a dog with seizures is essential to assess the effectiveness of the anticonvulsant and how the body is reacting to the seizure activity. Monitoring your pet at home for changes in the seizure pattern and recording this information is very useful when you visit the doctor regularly and helps in devising an accurate treatment for the dog's seizures.

5.2. Lifestyle Changes and Care

In many patients, making some basic changes can help manage seizures in combination with traditional medications. These changes affect a dog's health and the imbalance present in many conditions. Exercise or activity using energy and calories is helpful for controlling weight and maintaining good body and muscle tone; it can also delay the onset of age-related changes. However, physical activity or excitement may provoke seizures and change the body's systems to work for less stress and anxiety. What, when, and how much must be individualized for each dog in terms of nutrition. This is a science and provides balance for a lifetime, providing the body with what it needs to maintain health.

Repetitive, managerial families are especially important for dogs with epilepsy or other potentially very short seizures. Stress and anxiety in people and animals can be exacerbated or triggered. Some people know the signs or feelings they have before a seizure. Customizing your lifestyle, including reducing stress, is essential to provide a safe environment for each seizure. The room should be free from objects and other animals and have a soft floor to fall on to help prevent injury. Instruction and awareness are important. Owners must be able to predict their dogs' needs to make reasonable changes. General caution is still important for these dogs, including wearing identification marks and collars. Interaction in society can provide the owner with opportunities for learning and support. Trainers should be aware of the owner's affected dogs and any physical limitations and, if necessary, provide guidance on what the dog should be doing. Members of community groups are engaged in activities that help humans and animals understand the relationship between people and dogs. Veterinary visits can help educate practitioners and monitor the effectiveness of these and other treatments. Seizures sometimes cause injuries, and these individuals should be referred to a doctor. In a comfortable environment, comprehensive care, including exercise and diet, cannot be underestimated in the successful treatment of epilepsy in dogs.

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