EPILEPSY


WHAT IS IT?

The word EPILEPSY refers to repeated seizures (fit or convulsion) caused by excess electrical activity in the brain, which disrupts the normal communication between brain cells. The seizures indicate a sign of brain disease or disorder, much like a cough might be a sign of lung disease. In any event, it is a sign of a problem which unfortunately is usually not going to go away without further close investigation and/or treatment.

Epilepsy is one of the most common neurologic diseases in dogs. It is the tendency for the disorder to be so unpredictable that makes it such a complex disease with which to deal.  A seizure may occur as a one-off event from a variety of causes, but it is only if seizures repeat again and again over a period of time that it is called epilepsy.

Seizures are caused by excitatory influences on nerve cells in the brain, although there can be other causes that might tip the balance from inhibition towards too much excitation in the brain. It has nothing to do with the dog's emotional state, so any animal might fit if pushed past that threshold of electrical stimulation. Other influences that may cause a seizure might be toxins (poisonous plants, chemicals & insecticides), metabolic disease (low blood sugar or heart disease) and direct damage to the brain (injury or tumour).

Therefore, trying to identify the cause of a seizure is the first biggest challenge, as anything which damages the brain can cause epilepsy. If the cause of the seizure can be established, it is easier to determine whether the problem is primary or secondary. For example, if we are able to determine that the seizures are a symptom of a disease process that has been identified (e.g a brain tumour, stroke, chemical/hormonal imbalance), it can be said that the dog is suffering from symptomatic or secondary epilepsy. If a cause cannot be found, then it has to be assumed that the dog is suffering from idiopathic (of unknown cause) or primary epilepsy.

Seizures are divided broadly into two types: generalised and focal (or partial). Generalised is where the electrical storm in the brain arises everywhere at once.  In a focal or partial seizure, the abnormal electrical activity arises in a small area of the brain only.

HOW WILL I KNOW IF MY DOG IS HAVING A SEIZURE?

The most common time for a dog to have a seizure is when it is relaxed and quiet. In some instances, the dog can actually be sound asleep. However, seizures can occur at any time, but should they occur when the dog is exercising or excited, your Vet may look for another cause such a heart problem or low blood sugar.

The first phase is known as the aura or prodromal stage, which is the time when there is the earliest sign of a recognisable change in the dog's behaviour. This can alert the owner to an impending seizure. However, some dogs do not show aura, with the seizure coming out of the blue.

The dog is likely at this stage to show confusion, fear, rage or even seek attention or withdraw from his owner and hide (the tonic stage).

The classic seizure (tonic-clonic) begins with motor activity (rigid or jerky muscle spasms or paddling).  Once the seizure has begun the animal will fall to its side with legs outstretched and head back and may also lose consciousness, even though its eyes appear to be open. This will be accompanied by autonomic activity (salivation, urination and defecation). Changes in sensory function may lead to pawing at the face, tail chasing, or biting at part of the body or the air.

The tonic phase is usually brief (about 30 secs), but the clonic phase (rhythmic movements) can last up to 2 minutes. If the seizure goes on much longer and the dog goes into continuous seizure, it is a medical emergency requiring immediate veterinary attention.

It is important that during the clonic phase of the seizure, the owner ensures that all other pets and children are kept out of the way. Other than to give the dog plenty of space, make certain the dog is safe - that it cannot fall down the stairs, bang into a sharp edge, get tangled in an electric cord or otherwise cause injury to itself. It is not necessary to do anything, but keep a close eye on what is happening and keep a note of the time it takes for the seizure to abate.

The dog will not swallow its tongue, so please keep your hands away from its mouth.

Without a doubt, this is the most distressing time for the owner, as a seizure can often be both frightening to watch and emotionally overwhelming.

Following the seizure, the dog will lie motionless for some time, eventually slowly returning to normal. Often the dog will appear not to be able to see and is disoriented, pacing or running about the house, bumping into furniture, doors, tables etc. Sometimes this phase sees the dog as ravenously hungry and wishing to devour any food available. Although the dog at this time is unlikely to show aggression, it is wise to recognise the possibility that he may not behave as normal. Some dogs can bounce back immediately following a seizure and behave as if nothing at all has happened, whilst others are disoriented for days.

Most seizures are brief and isolated but seizures can come in clusters where the dog has a fit, recovers, and then immediately has another seizure. This could be the danger point for a dog to lapse into a continuous seizure requiring urgent and immediate medical attention. Any seizure lasting longer than 30 minutes is likely to cause the dog to fall into a coma or to cause serious brain damage. The seizure creates a tremendous stress on the heart and other organs, with the body temperature rising as a result of all the muscle activity.

HOW EPILEPSY IS DIAGNOSED?

Early evidence of epilepsy is usually seen within the first three years of a dog's life and it is acknowledged that several breeds (including the English Springer Spaniel) can be predisposed to develop the condition.  After this age, the seizures are more likely to be caused by an active disease process, such as infection, trauma, metabolic disorder or a tumour.

Since it is unlikely that Vets will witness a dog's seizures, they will be very dependent on the owner's description of what has happened.  Often early signs of a problem might go unnoticed, even by the owners themselves, and it is not until the dog has a full blown seizure that the dog is seen by a Vet.

Should your dog ever experience a seizure, it is hoped that the information you are able to provide will help to give your Vet a better clinical understanding of what has taken place.

Clinical diagnosis, for the most part, is made by an elimination process looking at the dog's history, by physical and neurologic examination, blood and urine analysis, bile acid assay and thyroid function tests, MRI and CT scans.  Determination of the type of seizure is critical to understanding the form of epilepsy from which the dog may be suffering.

There has been much discussion and debate over the years about the role of the thyroid in canine epilepsy. In view of the fact that the English Springer Spaniel is one of several breeds that are predisposed to immune mediated diseases (see Canine Autoimmune Disease), it is important for a Vet to establish whether there is any clinical evidence of thyroid dysfunction prior to the introduction of specific treatment for idiopathic (of unknown cause) epilepsy. This could be said to be true in cases where an ESS may start fitting later in life (after the age of 4 years), as it can be all too easy to assume idiopathic epilepsy, rather than search for another cause or causes.

All this underlines the importance of accurate clinical diagnosis on all occasions where seizures have been identified.

HOW IS EPILEPSY TREATED?

Treatment depends on factors such as the severity and frequency of the seizures.  Regular medication is used to control the seizures, with Phenobarbital being the drug most commonly used, as it is safe, effective and inexpensive.

Most dogs have very few side effects, but initially, until they develop tolerance to the drug, they can seem a little quiet or unsteady on their feet, as the Phenobarbital does have a sedative effect.

The other common side effect is an increase in thirst and appetite. As we know, decreased activity plus increased food intake can add up to an overweight dog, so it is important to adjust the diet for a dog on Pheonobarbital accordingly.

The owner will be asked to keep a careful note of any seizures, even though a drug is being administered. Blood levels of Phenobarbital are measured periodically, as well as indicators for liver and kidney function. Dosages may be adjusted if there are any changes in seizure frequency or severity or to keep in balance with any other medications that are being taken by the dog in question.

After a period of between 6 - 9 months, the Vet might consider a reduction in dosage and occasionally discontinue the use of anticonvulsant treatment.

Diazepam (valium) is also an effective drug used in the treatment of epilepsy, but if it is given daily there is always the possibility of it losing its effectiveness. Therefore, it is usually reserved for administration to the dog during a seizure, in the hope of arresting it.  It is given to the dog during an active seizure either by intravenous injection or more usually by suppository (per rectum). This has proved particularly helpful as a preventative treatment for dogs having cluster fits.

However, treating epilepsy is not quite like treating many other conditions, and missing a dose could have dire consequences. Ensuring a strict routine for giving medication, planning ahead to make sure you do not run out is vital.

IS THERE ANY EVIDENCE TO INDICATE THAT EPILEPSY IS INHERITED?

Unfortunately, many of the idiopathic epileptics will have a form of inherited epilepsy caused by a mutation in a specific gene, which has been inherited from their parents. The mode of inheritance is as yet unknown and will vary between breeds, and in fact it could be that more than one gene is involved.

Few breeds have yet to have proven hereditary epilepsy, but genetic studies and research projects continue to establish positive diagnoses of the hereditary form, so that take steps can be taken to decrease the incidence in the canine population. When evidence is seen of multiple epileptics in a family, it has to be a major concern that it may be hereditary. There are several genes associated with epilepsy in humans and mice, and these genes are being investigated as possible candidates for the culprit in canine epilepsy.

As both dogs and humans share the same environment, they can frequently be found to be suffering from the same complex diseases. As the genetic complexity is lower in dogs, it offers researchers a wonderful opportunity to pass valuable information on to their human research counterparts, so maybe allowing one day the possibility of our canine partners once again helping their human companions.

There is currently no UK based research into epilepsy that relates specifically to English Springer Spaniels.  However, there is a canine epilepsy study in the USA which includes English Springer Spaniels - for further information please see www.canine-epilepsy.net/cerc.html

In the UK, there is ongoing research (the LUPA project) focusing on epilepsy in the Border Collie.  For more information on this project, please see www.aht.org.uk, or email Dr Cathryn Mellersh at  cathryn.mellersh@aht.org.uk   

WHAT HELP OR SUPPORT IS AVAILABLE?

Epilepsy can be a most frustrating and distressing disease for both dog and owner alike.

Perhaps the most important factor to consider is the management of the condition. It is vital that both owner and Vet have a good understanding of what is required from each other. No owners should ever feel that they are inconveniencing or disturbing their Vet with queries or required medical assistance.

The best advice we can offer for those owners who are living with an epileptic dog is:

  • Try to plan ahead as best as you can to make sure that in the event of a seizure your dog is safe from hurting himself.
  • Keep calm and relaxed as best you can at all times, to convey to your dog that you are in control and he has nothing to worry about.
  • Do not stop having fun with your dog. Most epileptic dogs can live relatively normal lives, although requiring daily medication to control their condition.
  • Always make sure you have enough medication available (especially if you are away from home, or have left the dog in someone else's care, Bank holidays etc)
  • Feed a high quality balanced diet to suit your dog's needs and which is in balance with the amount of exercise he is taking.
  • Join an Epilepsy Support Group (see below), so that you can communicate with others who are in a similar position to you.
  • Establish a good, understanding relationship with your Vet. Ask him if he is willing to treat your dog holistically and is happy to discuss your fears and concerns.
  • Do not use dogs that have experienced seizures, their parents and siblings for breeding.

Owners of epileptic dogs wishing to seek the extra support needed in dealing with both medical and emotional aspects of the condition are recommended to contact:

The Phyllis Croft Foundation http://pcfce.org

or
The Canine Epilepsy Support Group www.canineepilepsysupport.co.uk

or
Canine Epilepsy http://www.canineepilepsy.co.uk/default.htm

 

 

 



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