Epilepsy

What does this mean?

Seizures in our domestic pets results in a loss or derangement of consciousness, altered muscle tone and often involuntary urination and defecation. In some cases the actual seizure may be preceded by minutes to hours of unusual behaviour, including hiding, attention seeking or agitation. Seizures are often followed by a short period of disorientation during which the animal may demonstrate general weakness, incoordination, blindness and pacing.

There are a number of causes of seizures. The onset, course, duration and frequency of the seizure activity may help determine the underlying aetiology. A sudden onset of frequent severe seizures most likely indicates a toxic, infectious, metabolic or neoplastic (cancer) process. A more insidious onset with intermittent seizure activity and no other neurological signs is most likely to be due to epilepsy.

Epilepsy is the most common cause of seizures in the dog. It is rare in the cat.

Breeds that are most frequently diagnosed with epilepsy include: German Shepherds, Keeshounds, Beagles, Dachshunds, Saint Bernards, Cocker Spaniels, Irish Setters, Miniature Poodles, Labradors and Retrievers.

Seizure activity usually starts between 6 months and 3 years of age. Seizures usually last 1 to 2 minutes and often recur at regular intervals, with weeks or months between the seizures. The affected animal is generally normal between seizures and consequently any laboratory tests we perform come back as unremarkable. Therefore, if we are presented with a young adult animal that is neurologically normal but has a non-progressive intermittent seizure disorder a diagnosis of epilepsy is often made.

Anticonvulsant medication is the only treatment for epilepsy. Not all animals require medication. Animals that have had only one seizure or have very short non-violent or infrequent seizures may not require treatment unless their condition progresses. However, the concern is that every time the animal has a seizure this may result in some degree of brain damage such that the seizure activity worsens over time or the animal dies as a result of cardiac or respiratory arrest.

Phenobarbital is the drug of choice for treatment of epilepsy. It is given twice a day. Side effects of Phenobarbital may include drinking more, urinating more, and an increased appetite. Should your animal become overly sedate, depressed, weak or incoordinated then we ask you to phone us and we will consider reducing the dose of medication. After 2 weeks of starting medication we take a blood sample from the animal and measure the phenobarbitone level. This tells us whether the dose the animal is receiving is adequate. This blood level is performed just before the animal receives its night treatment. Once the right dose has been determined we recommend that blood levels be performed every 6 to 12 months.

Phenobarbital alone controls seizure activity in most animals. If seizures continue then it may be necessary to add in another drug to the treatment protocol. The drug that we commonly try in this situation is Potassium Bromide.

Dr Lucy Micklethwaite