Epilepsy hard to define in dogs

EPILEPSY is caused by abnormal and repetitive electrical activity in the brain neurons. It is more than just convulsions, and seizures may be caused by a number of different factors. Thus it is difficult to diagnose and manage without lengthy and expensive evaluation of the canine sufferer.

The condition is the most common neurological illness suffered by the dog, but even though the electroencephalography (EEG) test for humans was introduced in 1929, it has never become a routine test for canine patients.

Epilepsy seizures result from abnormal discharge by specific neurons in the brain. The physical result may be an altered state of consciousness, or muscular, sensory or autonomic effects, noticed by the dog's owner or family members. Symptoms are usually repetitive, and may number from many events daily to one or two a year. However, environmental conditions have been observed to initiate both human and dog seizures. Known triggers include flashing lights, stress and sleep deprivation.

Epilepsy is not necessarily a long-term condition. It can go into remission spontaneously or can go into slow remission through anti-epilepsy drugs. If highly stressed, any brain can go into seizure. It is only when it happens consistently that an epilepsy diagnosis can be given, so accuracy in diagnosis is quite difficult.

During experiments oestrogens have been seen to speed the onset of seizures, and in an opposite effect progesterone tends to be inhibiting. The relationship between sex hormones and epileptic seizures has not been investigated in dogs, but the relationship might exist with normal hormonal fluctuations.

Epilepsy can occur in any canine breed or in mixed breeds. A predisposition towards epilepsy has been reported in the beagle, golden retriever, Labrador retriever, Shetland sheepdog, tervueren and keeshound. A recessive inheritance factor has been suggested in Bernese mountain dogs and Labradors.

Epileptic seizures are divided into two main categories - primary seizures and partial seizures. Regardless of the seizure type, the actual seizure is very brief.

Primary seizures involve both hemispheres of the brain and can be convulsive or non-convulsive.

Partial seizures originate from localised neurons and the signs depend on the location of the activation. They can be simple (if consciousness is not affected) or complex (if the consciousness is affected in some way). However, it can be difficult to gauge the degree of consciousness in a dog as natural responses differ and different dogs react in different ways.

In animals, confusion and difficulties recognising the owner may be interpreted as signs of affected consciousness. Haziness, however, remains unclear as animals cannot say what they are actually feeling during a seizure. It is debatable whether such signs in the dog, without an accompanying EEG test, are enough to offer a positive identification of the type of seizure the animal is experiencing.

Partial seizures may appear as leg or facial twitching, pupil dilatation, salivation or vomiting, all easy to recognise, but 'abnormal' behaviour is a diagnostic challenge. In humans, symptoms may be 'pins and needles', numbness, hallucinations, or strange smells. Symptoms such as those in a dog would go largely unrecognised.

Prodromes, or prolonged times (from hours to days) of altered moods, have been noticed by dog owners as well as by human sufferers of epilepsy as a lead-up to a seizure. In dogs the mood is usually one of restlessness and owners may learn to read the signs and be ready for the dog's impending seizure.

Vets are aware that when pet owners use terms such as epilepsy, seizures, fits etc they may be referring to conditions not associated with epilepsy and so it is vital that they investigate very closely what the pet owner actually has witnessed. Many other disorders can appear to be epilepsy, but they will usually be detected as long as the vet is thorough with his/her diagnostics.

Special care should be given not to confuse epilepsy with narcolepsy, cataplexy and syncope, among others, all which show symptoms that are common in epilepsy sufferers. Since veterinarians seldom have the opportunity to watch seizures in the patient, a very useful tool would be a home video taken by the owners during a dog's seizure. This would give the vet a better idea of the type of seizures the dog was experiencing.

Early treatment of epileptic seizures increases the success rate of seizure control, but the pet owner's attitude must also be taken into consideration. Some owners will tolerate a few seizures a year, while others will accept only seizure-free dogs. Epilepsy treatment can be a lifetime inconvenience or at least fairly long-term and while the ideal medications for humans demonstrate a huge range of choices the same can not be said for canine epilepsy medication because of toxicity, the length of time they stay in the body, their adverse side effects and even their cost. So considering the possible drugs for dogs, we are left with phenobarbital and bromide only, both often producing a range of side effects.

Owners of epileptic dogs should keep a diary of their dog's seizures, drug dosages, noticed side effects and anything else that may be helpful during vet visits, so that they do not forget any health detail that may be important to their dog's welfare.

Epilepsy is a challenging condition, but most affected animals can live a normal life with antiepileptic drugs. Owners need to remember also that their dog is not suffering - epilepsy in itself is not a painful illness, even though it can seem to doting and worried owners that their pet must be feeling pain. Human sufferers will confirm to such anxious pet owners that a seizure does not cause them pain or suffering. It is only if your pet has unusually bad and long-lasting seizures that cause it neurological or other damage that it may begin to experience a deterioration in its quality of life ... but that is caused by the damage, not by the seizure itself.

A dog with epilepsy should never be bred from, whether it has two seizures a day or two a year it still has epilepsy and can still pass it on.

Compiled from information given in various veterinary publications and websites.