Epilepsy affects 1-2% of the human population worldwide and is one of the most common neurological problems. As in humans, epilepsy in dogs is considered the most common neurological problem.
Epilepsy is a neurological disease that affects our dogs and cats. Seizures are disorders characterized by temporary neurological signs or symptoms that are produced by abnormal, paroxysmal and hypersynchronous electrical activity in the cerebral cortex.
It is very important to recognize the phases of the seizure so as not to confuse it with other types of pathologies such as syncope. Syncope is the loss of consciousness due to the reduction in blood supply to the cerebral hemispheres or the brain stem. Many times it can be very difficult to differentiate both.
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What is a seizure?
A seizure can be defined as a non-specific, paroxysmal, abnormal event in the body. An epileptic seizure is defined by the ILAE as “transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain”.
The clinical features of epileptic seizures can be separated into four components
How are the phases of the seizures?
- The prodrome is the time period prior to the onset of seizer activity. Owners report that they can “predict” the onset of their pet’s seizures, based on behaviour exhibited during this time, such as increased anxiety-related behaviour, reluctance to perform normal activity patterns and increase hiding (especially in cats)
- The aura is the initial manifestation of a seizure. During this period, which can last from minutes to hours, animals can exhibit stereotypical sensory or motors behaviour (pacing or licking) autonomic patterns (salivating, urinating, vomiting) and even unusual psychiatric events (excessive barking, increased/decreased attention seeking)
- The ictal period is the actual seizure event, manifested by involuntary muscle tone or movement and/or abnormal sensations or behaviour, lasting usually form seconds to minutes.
- The postictal periods follow the actual seizure and can last from minutes to days. During this time an animal can exhibit unusual behaviours, disorientation, inappropriate bowel and/or bladder activity, excessive or depressed thirst and appetite, or actual neurological deficits including weakness, blindness and sensory or motor disturbance. Often owners observe only the postictal period as evidence that their pet has had a seizure.
How do you classify the seizures?
- Self-limiting (isolated)- one seizure within 24 hours
- Clustered– two or more seizures, lasting <5 minutes each, within 24 hour but separated by a normal interictal period.
- Continuous – seizures lasting 5 minutes or longer, or without return to a normal interictal period, between seizures.
How is the differential diagnosis of seizures?
- Genetic (formerly idiopathic)
- Structural or metabolic (formerly symptomatic/ secondary and reactive)
- Unknown (formerly probable symptomatic/ cryptogenic)
How is epilepsy treated?
Management of epilepsy in cats and dogs often requires a lifetime commitment by the owners. The owner must be willing to medicate their pet several times per day, travel to emergency clinics at unpredictable times, follow up with periodic re-evaluations and diagnostic testing, and watch their pet carefully for adverse effects of therapy.
The balance between quality of life and therapeutic success is often a key issue for an owner to continue treating their pet. Despite all of the time, financial and emotional commitment, a significant portion of dogs may still continue to have seizures. Thus, proper client education is critical in preparing owners for understanding their pet’s condition and the potential associated lifestyle changes. In particular, owners need to know that a diagnosis of epilepsy implies in increased risk of premature death with the prognosis dependent on a combination of veterinary expertise, therapeutic success and the motivation of the owner.
Information obtained from BSAVA Manual of Canine and Feline Neurology.