Canine Epilepsy
What is Epilepsy?
It is a periodic disease which is characterised by seizures (convulsions) with partial or
complete loss of consciousness. Idiopathic epilepsy (of
unknown cause) is the most common type seen in dogs.
What are the signs?
Attacks usually commence without any warning, the dog falling to the ground, then
undergoing a series of muscular jerks. There is extension (stiffening) of the limbs,
followed by paddling and chewing movements. The eyes are fixed and staring. Loss of
control can result in salivation and passing of urine and faeces. Following an attack, the
dog gets up, looks around in a dazed manner and may run away with no idea of where it is
going. During an attack a dog should be left alone as they cannot swallow their tongue
(unlike people).
Attacks may occur frequently or
infrequently. Milder seizures, with the dog remaining conscious, may sometimes occur.
Which dogs are affected?
Although it can be seen in all aged animals, idiopathic epilepsy is generally seen in dogs
between 1 and 5 years of age. Seizures in dogs outside this age group are more commonly
caused by some other disease process. Although it is seen all breeds of dogs, there is an
increased occurrence in certain breeds e.g. German shepherds, Beagles.
What causes Epilepsy?
The cause of idiopathic epilepsy is still unknown although it is likely to be a genetic
problem in some breeds. A thorough veterinary examination including some pathology tests
are required to help distinguish idiopathic epilepsy from other causes of seizures, such
as nervous signs due to lead poisoning.
Can seizure episodes be prevented?
As the cause of idiopathic epilepsy is still unknown, there is no specific treatment to
remove the cause of the seizure. However, medication with appropriate drugs can either
prevent, or considerably reduce, the frequency and intensity of the seizures, enabling the
dog to lead a normal life. Although a number of drugs have been used to prevent seizures,
the initial drug of choice is Phenobarbitone. This is considered the safest
and most effective preventative therapy.
| Once phenobarbitone therapy is commenced, seizures may still occur
for up to 2 weeks until the required levels of the mediation are reached in the blood and
brain. Also, according to the animals response, the dose rate may have to be
adjusted during the course of the treatment. Dogs typically require medication for the
duration of their life. In most
epileptic dogs, control of seizures with phenobarbitone is usually successful. However,
some dogs develop an unresponsive form in which even very high doses of phenobarbitone are
ineffective. When this occurs, control may be achieved by the addition of a second drug, potassium
bromide which can be used in conjunction with phenobarbitone. The combination of
these two medications results in effective control and prevention of seizures in most
dogs. As with phenobarbitone, it can take several weeks before potassium bromide has an
optimum effect.
How can success of treatment be
monitored?
To assist in monitoring the success of treatment, the frequency of seizures should be
recorded on a calendar. Because one of the most common causes of poor control is too low a
dose of the medication (due to large differences in response between dogs), we may suggest
monitoring the levels of the medication in the blood. The dose rate of the medication can
then be adjusted according to blood levels and degree of seizure control.
Are there any side effects with
medication?
The main side effect with these medications used to effectively control epilepsy are
sedation and unsteadiness. This is generally seen at the commencement of treatment and
usually disappears after a short [period as the dog adapts to the medication. In a very
small percentage of cases, some effects on the liver can occur and it is therefore
recommended that on occasions, blood tests to assess liver function are undertaken.
Conclusion
Although epilepsy is a frightening disorder to both to the dog and the owner, treating
with phenobarbitone (and possibly in combination with potassium bromide) provides
effective control in most cases. This allows the dog to lead a full and active life when
maintained on the medication.
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