What is epilepsy?

Epilepsy is a neurological disorder characterized by repeated seizures due to abnormal electrical activity in the brain. For dogs, it’s one of the most common chronic disorders, and it can occur at any age, breed, or size. Seizures are often sudden and can range from mild to severe, affecting pets differently.

What is a seizure?

A seizure is a sudden, temporary disruption in normal brain activity that can cause various physical symptoms. In dogs, these symptoms might include muscle twitching, jerking, drooling, or even loss of consciousness. Seizures can last anywhere from a few seconds to several minutes, and they vary greatly in intensity.

 Types of Seizures

  1. Generalized Seizures: These affect the entire body and can be divided into convulsive epileptic seizures, causing symptoms like falling, convulsions (full-body jerking), and loss of awareness. Or non-convulsive epileptic seizures, or atonic seizures, in which there is a sudden and general loss of muscle tone resulting in collapse.

  2. Focal Seizures: These only impact one area, and can either stay focal or spread throughout the brain resulting in a generalised seizure. Focal epileptic seizures can present as motor seizures (e.g., facial twitching, repeated jerking head movement, rhythmic blinking and twitching of facial musculature), autonomic seizures (e.g., dilated pupils, hypersalivation or vomiting) and behavioural seizures (e.g., anxiousness, restlessness, unexplainable fear or attention seeking).

The Difference Between a Seizure and an Epileptic Seizure

  • Seizure: This is a general term for any sudden, abnormal burst of brain activity. Seizures can occur due to various causes, such as low blood sugar, toxin exposure, infections, or brain injuries. When a single seizure happens due to these factors, it doesn’t necessarily mean the dog has epilepsy.

  • Epileptic Seizure: This refers specifically to seizures that are part of a chronic condition called epilepsy. Epilepsy is diagnosed when a dog has recurring, unexplained seizures (not linked to other health issues). If a dog has two or more unprovoked seizures spaced apart, it’s more likely they have epilepsy, and the condition may require long-term management.

Not all seizures are due to epilepsy, and not every dog with a single seizure has epilepsy. Epilepsy is a medical condition where seizures are expected to recur over time, usually with no identifiable cause like injury or illness.

What are seizure triggers?

A seizure trigger is any factor or condition that can provoke a seizure in dogs. Triggers can vary widely among individual dogs and may include environmental stressors, medical conditions, and exposure to toxins. Recognizing and managing these triggers is crucial for pet caregivers to help minimize the risk of seizures and ensure their dog's well-being.

Remember that not all pets with epilepsy have seizure triggers, and for those that do, triggers might be different from pet to pet. In other words, not all pets whose seizures can be triggered have the same seizure triggers. Triggers may also be different from one pet to the next. For example, seizures may occur only during sleep or when waking up. Some pet caregivers may notice that their pet is more likely to have a seizure when not receiving enough sleep and others at times of high stress.

Potential Environmental Triggers in Dogs and Cats:

Stressful Situations:

  • Loud Noises: Thunder, fireworks, or sudden loud sounds can cause anxiety and trigger seizures, particularly in pets that are already predisposed to them.

  • Changes in Routine: Moving to a new home, the arrival of a new family member (human or animal), or significant changes in the household can induce stress and potentially lead to seizures.

Temperature Extremes:

  • Heat: High temperatures and humidity can lead to heatstroke, which may cause seizures in some pets, especially if they are left in a hot environment without adequate water or shade.

  • Cold: Extremely cold weather may also affect some animals, especially if they are not acclimated or are left outside for extended periods.

Lighting Conditions:

  • Flashing or Strobe Lights: Rapid changes in light intensity, such as those from strobe lights or even certain TV screens, may provoke seizures in some susceptible pets, similar to how they can affect some humans.

Chemicals and Toxins:

  • Household Cleaners: Exposure to toxic cleaning agents, pesticides, or certain air fresheners can trigger seizures.

  • Insecticides: Chemicals used for pest control, both in and outside the home, may be toxic to pets and could lead to seizure activity if ingested or absorbed through the skin.

Allergens:

  • Environmental Allergens: Allergens such as pollen, mold, or dust may cause reactions that lead to inflammation and potentially trigger seizures in sensitive animals.

Infections:

  • Neurological Infections: Environmental exposure to viruses or bacteria that can lead to infections affecting the nervous system, such as rabies or meningitis, can provoke seizures.

Physical Activity:

  • Overexertion: Intense physical activity, especially in high-stress or high-excitement situations, can lead to seizures in dogs and cats, particularly those predisposed to seizure disorders.

Travel:

  • Motion Sickness: Long car rides or travel-related stress can lead to seizures in some animals, especially if they are anxious during travel.

Why is recognising seizure triggers important in managing your pets’ epilepsy?

  • Preventing Seizures: Minimizing exposure to known triggers can reduce the frequency of seizures, leading to a more stable life for the pet.

  • Improved Veterinary Care: Keeping a record of triggers helps veterinarians diagnose and treat underlying causes more effectively.

  • Behavioural Understanding: Recognizing triggers allows caregivers to understand their pets' behaviours, aiding in better training and behaviour modification.

  • Enhanced Safety: Identifying triggers helps create a safer environment, reducing the likelihood of seizures occurring.

  • Better Quality of Life: Managing triggers leads to less anxiety and stress for pets, improving their overall well-being.

  • Medication Management: Understanding triggers can inform decisions about medication adjustments to optimize treatment plans.

  • Emergency Preparedness: Knowing triggers helps caregivers prepare for potential seizure events, making them more proactive during stressful situations.

  • Emotional Connection: Understanding a pet's triggers fosters empathy, strengthening the bond between the pet and owner.

 What are the stages of seizures?

Seizures in pets, including dogs and cats, typically progress through several stages, each with distinct characteristics. Understanding these stages can help pet owners recognize and respond appropriately during an episode. The stages of a seizure are as follows:

1. Preictal Phase (Promdrome)

This stage occurs before the seizure begins and thus does not form part of it. It is a long-lasting event and can take hours to days. Not all pets exhibit this phase. Signs may include changes in behaviour, such as increased anxiety or restlessness, seeking attention or hiding, or pacing or unusual vocalizations.

 2. Ictal Phase (Seizure)

This is the actual seizure phase, where the pet exhibits physical symptoms due to abnormal electrical activity in the brain. They can be categorised as generalised seizures (affecting the entire body) or focal seizures (localised to one area of the body). Signs often include body stiffening, jerking movements, or uncontrollable muscle spasms, loss of coordination or balance leading to falling, and excessive drooling, urination, or defecation. Some pets may exhibit odd behaviours such as biting or snapping at the air.

3. Postictal Phase

This stage occurs after the seizure has ended and can last from several minutes to a few hours, depending on the severity of the seizure. Signs may include disorientation or confusion (your pet may seem dazed or unresponsive), an increased thirst or hunger, temporary loss of motor function or difficulty walking, or fatigue or lethargy (your pet may want to sleep or rest).

Understanding these stages helps you recognize the signs of an impending seizure, the seizure itself, and the recovery process afterward. Knowing what to expect can make it easier to provide comfort and care during and after a seizure. If a pet experiences seizures, it’s crucial to consult with a veterinarian for appropriate diagnosis and management

What causes seizures?

Seizures in pets can happen when the brain reacts to a temporary problem, like a metabolic issue or exposure to toxins. These are called reactive or provoked seizures. Generally, this is reversible when the cause or disturbance is rectified. Examples of metabolic disorders are low blood sugar, liver disease, kidney disease or electrolyte imbalances.  

However, in most animals, seizures caused by epilepsy are the result of a disease of the brain which is prone to generate epileptic seizures. It is also defined as having at least two unproved epileptic seizures with more than 24 hrs apart. Therefore, if an animal only has displaying one single seizure and no further, strictly we cannot say the animal is epileptic as for this the seizures need to be repeatable.

Epilepsy can be divided in idiopathic epilepsy and structural epilepsy. Idiopathic epilepsy is a group of epileptic syndromes in which the cause of the seizures is either unknown or comes from the animals’ genes. Unfortunately,  In animals with structural epilepsy, the seizures are provoked by an abnormal or diseased part of the brain and causes for this may include vascular, inflammatory, traumatic, developmental, cancerous or degenerative diseases.  

How is epilepsy diagnosed?

Epilepsy in pets—especially dogs and cats—is diagnosed mainly by ruling out other possible causes of seizures. There isn’t one simple test for epilepsy, so vets follow a step-by-step process based on your pet’s health history, physical exams, and sometimes more advanced testing.

The aim is to figure out if your pet’s seizures are due to idiopathic epilepsy (meaning no clear underlying cause, likely genetic), or something else like toxins, infections, or brain disease.

The Tier System (Developed by the International Veterinary Epilepsy Task Force)

Vets use a Tier system to describe how confident they are in diagnosing idiopathic epilepsy. The higher the tier, the more tests have been done to rule out other causes.

Tier I – Basic Level

  • Based on:

    • A detailed seizure history

    • Neurological exam (normal between seizures)

    • Routine blood and urine tests (normal)

  • Used when the pet is otherwise healthy, and seizures started between 6 months and 6 years of age.

  • This level gives a probable diagnosis of epilepsy.

Tier II – Intermediate Confidence

  • Includes all Tier I criteria plus:

    • Bile acid test (liver function)

    • MRI brain scan

    • Spinal fluid (CSF) analysis

  • Used to rule out structural brain diseases, liver issues, or infections.

Tier III – Highest Confidence

  • Includes everything from Tier I and II plus:

    • EEG (electroencephalogram) to detect seizure activity in the brain

  • This level is rarely needed but gives the strongest diagnosis of epilepsy.

What are seizure mimics?

Seizure mimics in pets are conditions that produce behaviours or physical responses that resemble seizures but arise from different underlying causes. Proper identification of these conditions is critical for effective diagnosis and treatment. The most common seizure mimics are listed below:

  1. Syncope (Fainting)

    Syncope is a temporary loss of consciousness due to reduced blood flow to the brain, often caused by heart or circulatory issues. Pets with syncope may collapse suddenly, often appearing limp and briefly unresponsive. Unlike seizures, they typically recover quickly once blood flow is restored and usually do not experience the confusion (postictal phase) seen after a seizure.

  2.  Vestibular Disease

    Vestibular disease affects balance and coordination and is often seen in older pets. Signs include head tilt, loss of balance, circling, and rapid eye movements (nystagmus). Although it can mimic seizures due to sudden onset and dramatic presentation, it is a balance disorder rather than a neurological seizure.

  3. Narcolepsy and Cataplexy

    Narcolepsy involves sudden sleep onset, and cataplexy is a sudden loss of muscle tone often triggered by excitement or play. A narcoleptic pet may fall asleep suddenly, while during cataplexy, the pet collapses but remains alert and aware. This distinction helps differentiate it from seizure activity, which typically involves unawareness or loss of consciousness.

  4. Gastrointestinal Distress

    Severe abdominal discomfort, vomiting, or hiccups can mimic seizure-like movements. Pets may exhibit abdominal contractions, muscle spasms, or retching motions. These movements are usually associated with other signs of GI upset, such as drooling or gagging, rather than the neurological presentation of a seizure.

  5. Pain-Induced Episodes

    Sudden or severe pain can cause behaviours that mimic seizure activity. Pets experiencing pain may exhibit vocalizations, trembling, or muscle spasms, reacting to pain rather than neurological disturbances.

  6. Sleep Disorders (e.g., REM Behaviour Disorder)

    During REM sleep, pets may experience exaggerated movements that resemble seizures. Pets may paddle, twitch, or vocalize in their sleep. Unlike seizures, these movements stop when the pet awakens, and there is no postictal phase.

  7. Movement Disorders

    Movement disorders are neurological conditions that affect the control or coordination of movement. They often involve repetitive or involuntary actions, which may resemble seizure activity. The most common types of movement disorders are listed below:

  •  Tremors: Tremors involve rhythmic muscle contractions, often localized to the head or limbs. Tremors may be continuous or intermittent but typically don’t involve a loss of consciousness, distinguishing them from seizures. Commonly affected breeds include Chihuahuas and Bulldogs, which are prone to head tremors.

  • Peripheral nerve hyperexcitability in animals refers to an increased reactivity in the nerves outside of the brain and spinal cord, which can cause continuous muscle twitches or contractions. These twitches or muscle contractions vary in frequency and strength and are different from conditions like tremors (which have a steady rhythm) or myoclonus (quick muscle jerks).  These conditions in pets are often diagnosed with the help of an electromyogram (EMG), which records electrical activity in muscles. Identifying the specific type of hyperexcitability helps veterinarians determine the best approach to treatment, especially in pets who cannot describe their symptoms. Here’s a simple breakdown of types of hyperexcitability conditions.

  • Fasciculations: Small, visible muscle twitches that can be harmless or indicate an issue with motor neurons. In humans, fasciculations closer to the body are often benign, while those farther away from the center of the body may indicate nerve issues. Fasciculations have been seen in both people and pets.

  • Myokymia: These are bursts of muscle fiber movements within a muscle, creating a rippling effect. Myokymia is often due to potassium channel problems. It can appear as bursts of two or more muscle fiber twitches and may be harmless or point to an underlying problem. For example, certain breeds like Jack Russell Terriers are known to experience generalized myokymia, especially affecting facial muscles.

  • Neuromyotonia: This condition involves very high-frequency bursts of muscle activity that can happen on their own or when triggered by movement or tapping the muscle. The unique part is that these muscle contractions can continue even during sleep or anaesthesia. Neuromyotonia is sometimes associated with nerve changes that make muscles fire spontaneously.

  • Cramps: Muscle cramps are intense, sustained muscle contractions, often painful, that can result from electrolyte issues or underlying conditions like Addison's disease in dogs. These cramps involve high-frequency nerve firings and cause a gradual increase and then a decrease in the intensity of muscle contraction.

  • Tetanus and Tetany: Both involve continuous muscle contraction without relaxation. Tetanus usually refers to a condition caused by the tetanus toxin (from a bacterial infection), leading to rigid muscle contractions, especially in the limbs and face. Tetany is commonly due to low calcium levels, causing overactivity in the nerves, which can look like constant muscle rigidity without visible movement.

  • Myoclonus in pets refers to sudden, jerky muscle movements that can affect a single muscle or multiple areas across the body. These movements, often described as “shock-like,” resemble the quick jolt of an electric shock, and differ from tremors, which have a smoother, back-and-forth motion. Myoclonus can appear as single jerks in one muscle, multiple jerks in various muscles, or as generalized jerks involving many muscles simultaneously. Sometimes, these movements follow a patterned sequence across muscles or happen randomly across the body. Classifying myoclonus depends on where it originates within the nervous system. For instance, it might come from the brain’s outer layer (cortical), from deeper brain areas or the spinal cord (subcortical), or from peripheral nerves. In cases where myoclonus is part of an epileptic condition, it may accompany other types of seizures, making it more likely to originate from the brain’s cortex. A brainwave test (EEG) during these movements helps veterinarians determine if the myoclonus is linked to epilepsy or if it’s a standalone issue, guiding treatment options for the pet.

  • Paroxysmal dyskinesia (PxD) in pets refers to brief episodes of unusual, involuntary movements that come on suddenly and stop on their own. In pets, these episodes are often mistaken for seizures because they’re abrupt and unpredictable, but they’re actually different: PxD doesn’t cause unconsciousness, and pets don’t show signs of confusion or other symptoms typical of seizures after an episode. These episodes can occur randomly when the pet is at rest, although they can sometimes be triggered by sudden movement. During an episode, pets may show awkward or jerky movements, but between episodes, they appear normal, with no lasting neurological issues. PxD can be inherited (due to genetics) or acquired (due to factors like certain medications or brain injuries).

Seizure mimics, including movement disorders, can appear similar to seizures but often have distinctive characteristics. Accurate diagnosis is essential, as treatments vary depending on the underlying condition. Recording a video of any unusual episode and consulting with a veterinarian are vital steps to help distinguish between true seizures and seizure mimics, ensuring the pet receives the appropriate care.