Seizures in dogs can be a frightening experience for both pets and their owners. While the image of a dog having a grand mal seizure—with its dramatic full-body convulsions—is the most recognized, seizures manifest in various forms, stemming from a range of causes. Understanding these different types, their potential origins, and available treatment options is crucial for providing the best care for your canine companion.
Types of Seizures in Dogs
Seizures are broadly categorized into generalized and focal types, based on the extent of brain activity involved.
Generalized Seizures
These seizures involve abnormal electrical activity across both hemispheres of the brain.
- Grand Mal (Tonic-Clonic) Seizure: This is the most common and dramatic type. It’s characterized by the dog suddenly collapsing, experiencing violent, jerking spasms in all four limbs (paddling), foaming at the mouth, potential loss of bladder and bowel control, and unconsciousness. During such an event, your priority is to ensure your dog’s safety by removing nearby hazards. Avoid putting your hands near their mouth, as they are not aware of their surroundings and could bite unintentionally. It’s also important to time the seizure, as prolonged seizures can lead to a life-threatening condition.
- Status Epilepticus: Defined as a seizure lasting longer than five minutes or multiple seizures without full recovery in between, status epilepticus is a medical emergency. The intense physical activity can cause a dangerous rise in body temperature and requires immediate veterinary intervention, typically with intravenous medication.
- Other Generalized Seizures: These include tonic seizures (stiff, extended limbs), clonic seizures (hyper-flexed, non-jerking limbs), myoclonic seizures (jerking limbs), and atonic seizures (sudden loss of muscle tone, causing the dog to collapse).
Focal Seizures
Focal seizures occur when abnormal electrical activity is confined to a specific area of the brain.
- Presentation: These can manifest in various ways, such as “fly-biting” behavior (snapping at imaginary flies), “chewing gum fits” (repetitive jaw clacking), or localized twitching of an eyelid, lip, or ear. Consciousness may not be lost.
- Treatment: Focal seizures often do not require treatment unless they escalate into a generalized seizure, in which case close observation is necessary.
Causes of Seizures in Dogs
Seizures can be triggered by a variety of factors, broadly classified as reactive or structural.
Reactive Seizures
These occur due to temporary conditions affecting the brain’s environment.
- Metabolic Disorders: Low blood sugar (hypoglycemia) or calcium levels (hypocalcemia), liver disease, liver shunts, and kidney disease can all trigger seizures. If the underlying metabolic disorder is corrected, the seizures typically cease.
- Drug-Induced Seizures: Certain medications can lower the brain’s seizure threshold. Discontinuing the offending drug can resolve these seizures.
- Toxins: Ingestion of substances like caffeine, xylitol (a sugar substitute), antifreeze, rat poison, and alcohol can cause seizures. Promptly removing the toxin and providing supportive care is essential.
Structural Seizures
These are caused by physical abnormalities within the brain itself.
- Brain Abnormalities: Tumors, head trauma, inflammatory diseases (like meningitis), and infectious diseases such as rabies and canine distemper can lead to structural seizures.
- Idiopathic Epilepsy: This is the most common cause of seizures in dogs, characterized by recurrent seizures of unknown origin. A diagnosis of idiopathic epilepsy is typically made after all other potential causes have been ruled out through diagnostic testing. It usually begins between 6 months and 6 years of age. Certain breeds, including Schnauzers, Collies, Basset Hounds, Cocker Spaniels, Labrador Retrievers, and Golden Retrievers, have a higher predisposition to epilepsy.
Age-Related Risk Factors: Dogs under one year are more prone to congenital defects, intoxication, or infectious diseases. In contrast, dogs over six years experiencing their first seizure are more likely to have a metabolic disorder or a structural brain lesion, such as a tumor or stroke.
Diagnosis and Treatment
Diagnosing the cause of seizures often involves a thorough physical examination, neurological assessment, and diagnostic tests like blood work and, in some cases, advanced imaging such as MRI.
When to Start Treatment
For dogs between 6 months and 6 years old with normal test results, many veterinarians do not recommend immediate antiepileptic drug (AED) therapy after the first seizure. However, exceptions include cluster seizures, particularly violent seizures, seizures lasting longer than five minutes, or in breeds with known difficult seizure prognoses.
Starting AEDs is a significant decision, as these medications are typically required for life. The goal is to improve the dog’s quality of life without causing undue side effects from medication. A seizure log detailing frequency, duration, and severity is invaluable in determining when treatment should commence. A general guideline is to consider AEDs if seizures occur more than once a month, as this frequency can significantly impact a dog’s and owner’s quality of life.
Commonly Used Medications
Several effective anticonvulsant medications are available for dogs:
- Phenobarbital: A long-standing and effective treatment.
- Levetiracetam (Keppra): Known for its efficacy and minimal side effects. The extended-release formulation (Keppra XR) offers more convenient twice-daily dosing.
- Zonisamide: Another option with a good side-effect profile.
- Potassium Bromide: Often used in conjunction with other medications.
- Topiramate: May be considered by your veterinarian.
Approximately 20% of dogs develop refractory epilepsy, meaning they require more than one AED to manage their seizures. In some cases, dogs can develop a tolerance to their medication over time, necessitating higher doses and potentially increasing side effects.
Other Therapeutic Options
Beyond daily medications, several other therapies can help manage seizures:
- Rectal Diazepam or Intranasal Midazolam: These benzodiazepines can be administered at home to help shorten or lessen the severity of a seizure.
- Pulse Keppra Therapy: For dogs prone to cluster seizures, a veterinarian may prescribe levetiracetam for occasional use to prevent seizure clusters.
- Adjunctive Therapies: Gentle vagal nerve stimulation, such as applying pressure to closed eyelids, may help reduce seizure duration and severity.
- Traditional Chinese Veterinary Medicine (TCVM): Acupuncture and Chinese herbal remedies, administered by a TCVM specialist, can complement conventional treatments and potentially reduce seizure frequency or medication dosage.
- Prescription Diets: Special diets, like Purina Pro Plan Veterinary Diet NeuroCare (NC), which contains medium-chain triglycerides (MCTs), have shown promise in reducing seizure activity in some dogs.
Managing seizures in dogs requires a collaborative approach between pet owners and veterinarians. By understanding the different types, causes, and available treatments, you can work with your vet to develop the most effective management plan for your beloved companion.
