Belinda Comito, DVM, DACVIM (Neurology/Neurosurgery)
Primary epilepsy is a common, chronic neurologic disease in companion animals. This disease is defined as recurrent seizures without an underlying cause. Primary epilepsy is diagnosed by excluding other causes by having normal lab work, MRI, and Cerebrospinal fluid (CFS) analysis. Often veterinarians are working under a presumptive diagnosis.
Primary epilepsy affects patients ages of 1-6 years, occasionally younger or older. Any breed may develop the disease but some breeds are more prone (Australian Shephards, Border Collies, Poodles, Belgian Tervurens) and some breeds are more difficult to control.
Managing seizures can be challenging and seizure management cannot be “cook booked”. Each patient presents their own unique challenges in management. Below summarizes the common pitfalls in seizure management.
It’s not a seizure
Sometimes challenging cases to manage are not actually seizures. Several conditions may be mistaken for seizures such as head tremors or vestibular signs. Getting a thorough history from the family and characterizing the event is extremely important. Patients with seizures will often have an aura (pre-seizure changes), ictus (seizure event), post ictal (post seizure changes).
The goal of management is to reduce the frequency and severity of seizures. Establishing baseline goals helps families understand the disease and manage stress. Adequate control is considered one seizure per month. Regardless of how well controlled a patient becomes there is a risk for future seizures. A family should be prepared for daily medication and side effects, lab work requirements, and the possibility of needing more than one medication. Therapy is often lifelong and seizure frequency can wax and wane making seizures unpredictable. Open communication and building a team atmosphere is needed to support families.
Guidelines for starting medication include having more than one seizure monthly, cluster seizures, or a severe seizure lasting longer than 3-5 minutes. When starting medication several factors are considered: concurrent medical issues, feasibility of administration, medication side effects, and medication cost. Once a medication is started it is often lifelong. If the seizures become controlled families may want to discontinue medications. Unfortunately, the seizures may come back more severe and are not always as easily controlled with medication.
Medication adjustments are recommended when a patient is having unacceptable side effects or when the seizures are poorly controlled. If a patient has poorly controlled seizures, generally the first medication is exhausted and will be increased under the advice of the veterinary team. The goal is to use the fewest medications possible.
Unfortunately, there is always risk for breakthrough seizures because the disease waxes and wanes. Families should report seizures when they occur. A medication change is not always necessary and depends on the frequency and severity of seizures. Sometimes there can be reasons for breakthrough seizures. Common reasons include developing medication tolerance, low medication levels, inappropriate medication dosing, or rarely a new cause for seizures has developed. A seizure emergency is a seizure longer than 3-5 minutes, 3 seizures in 24 hours, or cluster seizures. When seizure emergencies occur medication changes are made to stop the emergency and improve future seizure cycles. Hospitalization is generally recommended for patients in a seizure emergency.
Success is challenging to define. The goal is controlling seizures while minimizing medication side effects. Medication side effects may be more impactful on a patient’s quality of life than the seizures. Success is dependent upon the family’s perception of the seizure frequency/severity and medication side effects. Families experience high stress levels from the unpredictability of seizures, daily medication needs, and cost. Success should be weighed on seizure reduction, minimizing medication side effects and costs, and avoiding hospital stays.
Belinda Comito is a boarded Neurologist and Neurosurgeon at Veterinary Specialty Center.