Epilepsy is the name given to seizure disorders in dogs and cats for which there is no identifiable cause. Primary epilepsy is the result of functional cerebral disturbances without obvious causes other than a possible hereditary predisposition. For a diagnosis of epilepsy to be made, other causes of seizures including poisoning, infection, tumors, and cranial trauma must be ruled out through diagnostic testing. While true epilepsy can occur in pets of any age, most commonly pets with epilepsy begin demonstrating seizures between 6 months to 5 years of age. Seizures occur in epileptic pets as hyperexcitable neurons within the brain show activity. As the development of progressive and refractory seizures correlates with the number of seizures, early diagnosis and treatment are important in preventing a worsening of future seizures. In people, seizure triggers have been defined for some epileptics. Triggers probably do occur in pets but have not been well defined and most owners can't identify what causes seizures in their pets. Generalized (grand mal) seizures are the most common form in pets; petit mal seizures are extremely rareand possibly not even noticed by most owners if and when they occur.
Generally, conventional antiepileptic medicine is not prescribed unless the pet has at least 1 seizure per month, as the goal of treatment is to reduce, rather than eliminate, seizure frequency, severity, and length. This is because we can't ever guarantee that a pet won't have further seizures, and it's important for owners to have realistic expectations of treatment.
Conventional Therapy:
Conventional therapy involves various anticonvulsant medications including phenobarbital, potassium bromide, or diazepam (Valium.)
Phenobarbital is commonly used to control seizures in dogs with epilepsy. Side effects include increased thirst, urination, and appetite; occasionally, excess sedation and a wobbly gait are seen, especially as the dosage increases. Increased liver enzymes, that may or may not be associated with liver damage, can be seen, as can anemia. Dogs taking phenobarbital should be reevaluated periodically and have regular blood profiles to monitor side effects and therapeutic blood levels (generally every 3-6 months.)
Potassium bromide is not officially approved by the FDA for use in dogs. It has become a popular medication for the control of seizures in dogs and has been used successfully for several years. It appears to be a safer medication than phenobarbital (fewer side effects,) although phenobarbital rarely produces any significant side effects in dogs. Potassium bromide can be used in dogs as the sole therapeutic agent, in combination with phenobarbital (if needed,) or in place of phenobarbital for those dogs whose seizures are not adequately controlled with phenobarbital or who suffer from secondary liver disease as a result of phenobarbital therapy. Many doctors are now using potassium bromide as the initial (and often only) medical therapy for dogs with epilepsy. Side effects of potassium bromide may include tremors, stupor, wobbly gait, lack of appetite, vomiting, and constipation. Potassium bromide may rarely cause pancreatitis when it is used in combination with phenobarbital or primidone (another anticonvulsant that is rarely used in dogs.) Dogs placed on low salt diets may have increased bromide toxicity as a result of decreased chloride ion levels. Extra salt in the diet, as well as use of diuretics, may decrease the blood levels of bromide and increase the frequency of seizures. Dogs taking potassium bromide should be reevaluated periodically and have regular blood profiles to monitor side effects and therapeutic blood levels (generally every 3-6 months.)