Canine Epilepsy

What is Epilepsy?

Epilepsy means “repeated seizure,” which is a sudden recurring attack with or without loss of consciousness.  It is the most common long term chronic neurologic disease in the dog and can affect 1 in 130 dogs.

What can cause Epilepsy?

The underlying cause of epilepsy is not yet fully understood but it is thought to arise from a dysfunction in the brain’s electrical activity.

There are 2 main types of Epilepsy

1. Idiopathic Epilepsy.  Affected dogs usually have their first seizure between 6 months and 6 years of age, but usually between 10 months and 3 years.  Any breed of dog can be affected, and no underlying cause can be identified.  In some breeds however, it is assumed to have a genetic basis.  This is seen in approximately 26 different dog breeds including Beagles, All Shepherds, Springer Spaniels, Keeshond, Golden Retriever, Vizsla and the Labrador to name but a few. 
2. Structural Epilepsy.  This is diagnosed when there is underlying damage to the brain triggering seizure activity, such as tumours, bleeding abnormalities, or inflammation. 

What are the Clinical Signs?

There are 3 phases of a seizure.

1. Preictal phase.  This is sometimes called the ‘aura’ and in humans is a sensation just prior to the seizure.  Your dog may show altered behaviour and may appear anxious or restless.  This phase can be very subtle and often missed. 
2. Ictal phase.  This is the actual seizure itself and often occurs when the dog is resting or asleep. See below.
3. Post Ictal Phase.  This is the immediate period after the seizure.  Your dog may lie still for a while and then attempt to get up.  Often they can be restless, disorientated, they may stagger, urinate/defaecate and even may have temporary loss of sight.  This phase may last a few minutes to several hours.

The seizure itself can be 2 main types:

1. Focal Seizures.  This is a seizure that occurs in only half of the brain or in one specific area. Seizure type depends on which part of the brain is affected.  They may just have muscle contractions in one area eg facial twitching, rapid blinking or rhythmic contraction of one leg.  Or alternatively, may have behavioural changes, such as vocalisation or fearfulness.  It may also affect a body system and cause signs such as salivation or urination.  Focal seizures can often progress to generalised seizures.
2. Generalised Seizures (Grand Mal).  This is a seizure involving both sides of the brain.  Your dog will often collapse to one side with their head back and loose consciousness.  There is often rhythmic jerking, spasms, or paddling of the legs and chomping of the jaws with salivation. Your dog may also defaecate and urinate during the seizure.  This phase usually only lasts 1-2 minutes but can seem like a lifetime whilst watching your dog.  Try to stay calm and move any furniture out of the way so they cannot injure themselves ,and keep hands away from the mouth so as not to get bitten.  Remember they are not conscious so will not be feeling any pain or distress.  Try to time how long the seizure lasts.

When to call the vet

Usually the seizure is over in 1-2 minutes and your dog will recover uneventfully.  However, if your dog has 2 or more seizures within 24 hours this is called a cluster seizure and often requires medical intervention – ring your vet.  Another medical emergency a condition called Status epilepticus.  This is when your dog has a seizure that lasts 5 minutes or more, or your dog has 2 or more consecutive seizures without recovering between seizures.  If untreated your dog could be left with permanent brain damage or die – your need to get your dog to the vet as soon as possible.

How can my Vet diagnose Epilepsy?

In between seizures, a dog with idiopathic epilepsy will appear completely normal.  A physical examination by your veterinarian will also reveal no abnormalities.  It is therefore important that you are able to give your vet as much information about the seizure event as possible.  Information like what was the dog doing prior to the event, what actually happened, how long was the event and how long did it take for your dog to recover.  Your vet will then do a complete physical examination including a neurological exam – looking for subtle changes that may indicate underlying structural damage to the brain.  I would also recommend full blood tests, urine test and possibly testing for infectious diseases to check for other underlying causes.  If your vet finds any indication of structural brain damage, or your dog falls out of the age group for idiopathic epilepsy, they may suggest referral for further imaging of the brain, or collection of fluid from around the brain (CSF tap)– this is to check for structural epilepsy.   

How is Epilepsy Treated?

It is important to note that idiopathic epilepsy is a lifelong disease and cannot be cured, only managed.   Many medications are available that supress the excess electrical activity in the brain.  Once medication is started it is given lifelong, so it is important to know when to start.  There are different criteria, but usually your veterinarian will recommend starting medication when your dog has had 2 seizures within 6 months, they have had a cluster seizure, status epilepticus or have severe signs post ictal (after the seizure).   Anti-epileptic drugs can have many side effects such as sedation, increased appetite/thirst or liver inflammation.  Some of these side effects are transient, but if they persist it may necessitate changing drugs. It is also important to give the medication regularly and at the correct dose, as failure to do so may precipitate a seizure.  Be aware that these medications only stop seizures altogether in 15-30% of dogs, most dogs continue to have seizures but with less frequency.  Some dogs many need a combination of drugs to improve seizure control.  Keeping an epilepsy diary is a great idea as it will help to determine if the drugs are working and if there are any triggering factors.

Your dog will need regular check-ups with your vet which may include blood tests. This is to monitor for side effects, or to check blood drug levels.   Most dogs with idiopathic epilepsy, however, can have an excellent quality of life.