What is epilepsy?
Epilepsy is a chronic condition that causes repeated seizures
(which may be described by terms such as 'fits' or 'funny turns'),
and is the most common chronic (long term) neurological disorder in
dogs, affecting an estimated 0.6-0.7% of all dogs in the UK alone
(around 1 in 130 dogs).
In most cases epilepsy is a lifelong disease. A seizure occurs
when there is abnormal electrical activity in the brain which leads
to sudden but short-lived changes in a dog's behaviour and/or
movement. Some breeds may be more predisposed to epilepsy than
others and their prevalence may be higher than others. Epilepsy may
run in some families and pedigree studies have demonstrated a
hereditary basis for some types of epilepsy in a number of
What are the signs my dog may be epileptic?
Your vet may suspect that your dog has epilepsy if they have at
least two unprovoked epileptic seizures more than 24 hours apart.
It can be difficult for vets to tell the difference between
seizures and other health problems, so providing them with a
thorough description of the abnormal event, or ideally a video
recording, can help them in their diagnosis. Three main
characteristics of epileptic seizures are:
- Loss of voluntary control, often seen with convulsions (jerking
or shaking movements and muscle twitching)
- Irregular attacks that start and finish very suddenly
- Attacks that appear very similar each time and have a
repetitive clinical pattern.
Are there different types of seizures?
There are several types of epileptic seizure, but how they
affect one dog can be different to how they affect another. Some
dogs have more than one type of seizure, and not all seizures
involve convulsions). Most epileptic fits usually happen quite
suddenly without warning, last a short time (often only a few
seconds or minutes) and stop by themselves. Injuries can happen
during seizures, but most dogs do not hurt themselves and do not
need to go to the vets unless epilepsy has not been diagnosed.
The names of the seizures used here describe what happens during
1. Focal seizures
These only occur in one half of the brain and within a
particular region. How these types of seizures present themselves
depends upon where in the brain the abnormal electrical activity
started, and the function of that part of the brain. Focal
epileptic seizures can present as:
- Episodic movements ("Motor" signs) e.g. facial twitches,
rhythmic blinking, head shaking or repeated muscle contractions of
- Autonomic signs (arising from the autonomic nervous system)
e.g. excessive salivation, vomiting, dilated pupils
- Behavioural signs (episodic changes in the dogs behaviour) e.g.
restlessness, anxiety, attention seeking, unexplainable fear
2. Generalised seizures
These occur within both sides of the brain. Generalised
seizures may occur alone or may start as a focal seizure and evolve
into a generalised seizure (see below - point 3). In most cases of
generalised seizures the dog loses consciousness, and salivation,
urination and defecation may occur. Motor movement occurs on both
sides of the body. Aspects of generalised seizures are often termed
tonic, clonic, tonic-clonic and myoclonic. These terms are defined
- Tonic: Increase in muscle contraction (stiffening) lasting from
seconds to minutes
- Clonic: Involuntary rapid and rhythmic contractions of muscles
- Tonic-Clonic: A sequence of a tonic phase followed by a clonic
- Myoclonic: Sporadic jerks usually on both sides of the
Generalised seizures can also be non-convulsive, such as atonic
seizures (also called drop attacks), which result in a sudden and
general loss of muscle tone which usually causes the dog to
3. Focal seizure evolving into a generalised seizure
This is when a generalised seizure follows on from a focal
seizure. This is the most common seizure type observed in
dogs. The focal seizure is often very short (few seconds to
minutes) and the secondary generalisation follows rapidly.
The focal seizure may be difficult to detect due to its brief
nature and it is important to tell your vet what happened before
convulsions started, to help them determine what type of seizure
your dog is having.
What causes epilepsy?
A number of different underlying diseases and other factors can
cause seizures leading to epilepsy. Generally, epilepsy can be
classified as 'structural' (where an underlying cause can be
identified in the brain) or 'idiopathic' (where no underlying cause
can be identified, and a genetic predisposition is often presumed
or the cause is unknown).
1. Idiopathic Epilepsy
Idiopathic epilepsy usually affects young to middle age dogs (6
months to 6 years old) in which no underlying cause for repeated
seizures can be found. Idiopathic epilepsy is often assumed to be
due to a combination of genetic and environmental factors. To
diagnose idiopathic epilepsy, known causes, such as certain
diseases, must first be ruled out. The diagnosis should be based on
your dog's medical history, a neurological examination and
laboratory tests (blood and/or urine). Further assessments such as
imaging the brain using MRI and analysing your dog's cerebrospinal
fluid, may be recommended by your vet to detect abnormalities that
could be causing the seizures.
2. Structural Epilepsy
In other dogs experiencing seizures, an underlying cause can be
found in the brain. This includes problems with blood supply,
including obstructions, as well as bleeding, inflammation,
infection, trauma, developmental problems, brain tumours and
degenerative brain diseases. These abnormalities can be confirmed
by either MRI and/or cerebrospinal fluid analysis. In addition to
these structural causes, metabolic disorders of the brain can lead
to a change in its structure and neuronal degeneration. For
example, Lafora's disease (which affects some Miniature Wire Haired
Dachshunds, Basset Hounds and Beagles) is caused by a gene defect
that leads to a 'storage disease' (where a toxic substance
accumulates in cells), changing the structure of the brain and
leading to seizures.
3. Reactive seizure
A reactive seizure usually occurs in response to a temporary
problem in brain function, which may be as a result of metabolic
changes or poisoning - which is reversible when the cause or
disturbance is rectified.
What should I do if my dog has a seizure?
It is important that you stay calm. Most seizures are brief, and
dogs are usually totally unaware of them. Affected dogs are
not likely to suffer during the seizure, even if they appear
violent. Make sure you and your pet remain safe by moving any
furniture out of the way so that your pet cannot hurt themselves.
Under no circumstances should you put anything in your pet's
mouth, including your hands.
Your vet may prescribe 'emergency medication' to reduce the
length of an epileptic episode. Most seizures only last 1-2
minutes, but it is a good idea to time the seizures so you are sure
of its length. It is very helpful to carefully observe the seizure.
In particular, what were the first signs? Was one side of the body
affected first? What sort of movements did your pet exhibit, e.g.
paddling movements, shaking, chewing or chomping? Records of these
observations along with your seizure diary will be very useful
information for your vet.
How often a dog with epilepsy experiences seizures can vary
greatly between dogs and over an individual dog's lifetime.
Recording how often your dog has seizures is important to track how
well their treatment is working, and so your vet can alter their
treatment if necessary. Some dogs experience seizures very close
together in time (e.g. more than one in a day), seizures that are
very long, or seizures that immediately lead to more seizures,
which they do not return to normal in-between. These types of
seizure pose a particularly high risk to your dog's health, can be
life-threatening and an emergency:
1. Cluster seizures
A cluster seizure occurs when a dog has two or more seizures
within a 24-hour period. Cluster seizures occur in around one third
to three quarters of dogs with idiopathic epilepsy. Some breeds of
dog may be more prone to cluster seizures including the German
Shepherd Dog, Border Collie, Boxers, Cavalier King Charles
Spaniels, Staffordshire Bull Terrier and Labrador Retriever. If
your dog has cluster seizures, emergency medication may be
prescribed by your vet for home use. These medications are
administered if a cluster seizure occurs, to try and stop the
seizure and to prevent more from occurring. You should never
attempt to put anything in your dog's mouth, including your hands
during a seizure. Although cluster seizures can be treated at home
with medication, such as rectal diazepam or levetiracetam pulse
therapy, you should also contact your vet for further advice and/or
changes in treatment to try and avoid clusters occurring in the
2. Status epilepticus
Status epilepticus is classed as either (a) a seizure that lasts
longer than 5 minutes, or (b) where two or more individual
epileptic seizures occur, between which the dog does not return to
'normal' and regain full consciousness. Immediate treatment is
necessary because status epilepticus can cause permanent
neurological damage or even death. If status epilepticus occurs in
your dog, immediately contact your vet for emergency treatment.
Emergency treatment includes your vet administering high doses of
medications that try to stop the seizure and minimise damage to
your dog's brain and body. Although seizures are distressing to
witness, you should always try to stay calm when a seizure starts
and time how long it lasts, so you know whether a seizure is
lasting a particularly long time, and are prepared to contact your
vet if status epilepticus occurs.
What can trigger my dog's epilepsy?
Some dogs may appear to have 'triggers' that lead to a seizure,
while others do not. Identifiable triggers may differ from dog to
dog. In people with epilepsy, common triggers include tiredness and
lack of sleep, stress, and not taking medication. Stress is a
trigger commonly reported by owners, and may be caused by a variety
of situations including changes in the environment, changes in
routine, car rides, thunderstorms, and visits to the vets to name a
few. Other owners report certain foods or medications seem to
trigger seizures in their dog. Keeping a seizure diary may help
identify triggers in your dog.
What treatment options are available and can epilepsy be
In most cases, epilepsy in dogs cannot be cured. Maintaining a
seizure-free status without causing unacceptable side effects is
the ultimate goal of antiepileptic drug (AED) therapy. This balance
is achieved in 15-30% of dogs. The goal of medical treatment is
therefore to improve your dog's quality of life by minimising how
frequently the attacks occur and how severe they are.
Additionally, the medications chosen for this should not cause
serious side effects.
If your vet recommends commencing AED therapy, ensure you
discuss this thoroughly so that you understand the importance of
this treatment and why it is necessary. Your vet will be able to
support you with this treatment, and regular health checks should
be arranged so you can both monitor for adverse effects of the
idiopathic epilepsy or the medication. Once started, AED treatment
is continued indefinitely, in most cases for the rest of your dog's
life, with periodic health checks and blood tests to ensure correct
drug dosage, treatment efficacy and minimal treatment-related side
Your vet will be able to advise you as to which antiepileptic
drug (AED) is most suited to treating your dog's epilepsy. Factors
that may influence your vets decision may include the type of
seizure your dog experiences, how often they seizure, and if they
have any problems with their kidneys or liver. The first
medications your vet can legally prescribe to treat your dog's
epilepsy in the EU are either Imepitoin or Phenobarbital.
If the desired reduction in seizures is not seen with the 'first
line' medications, they may choose to 'add-on' Potassium Bromide as
a second medication. There are several AEDs used to treat epilepsy
in humans that are being used to treat epilepsy in dogs; however,
these medications can only be used if the approved treatments have
failed. Always keep your dog on a constant diet as changes to what
your dog eats can change blood levels of certain drugs.
new diets are currently being developed, which might help to
improve seizure control even further.
It is very important that you:
- Give your pet their medication at the same time every day
- Give them the correct dosage of medication
- Continue their treatment and do not stop without first
discussing with your vet
How do I know if the drugs are working?
Antiepileptic drug treatment is generally considered to be
successful if the frequency of their seizures is reduced by at
least half, though seizure freedom should be aimed for. To
determine whether the medication is working, an accurate seizure
diary is required. From this you can track patterns in your dog's
seizure frequency and severity to see if improvements are
How can I monitor if the drugs are working?
The Royal Veterinary College (RVC) have created an app (
RVC Pet Epilepsy Tracker) which allows owners to electronically
track seizures on their smart phone.
Do these drugs have side effects?
Your dog may experience side effects of their AED treatment. The
effects may occur soon after treatment starts or their dose is
increased. These effects generally disappear or decrease in
the subsequent weeks due to your dog's body developing a tolerance
to these drugs. In some cases these side effects persist and must
be monitored to ensure their severity does not compromise your
dog's quality of life. Side effects vary with different AEDs.
Potential common side effects of AED treatment include
sleepiness, wobbliness, increased appetite and thirst, drooling,
vomiting, diarrhoea, weakness of the back legs, weight gain,
excitability, restlessness and behavioural changes. If your dog
stops having seizures, or your dog experiences life-threatening
side effects then your vet may recommend that the AED treatment is
stopped. Never stop treatment immediately as this can in itself
cause seizures and status epilepticus - please consult your vet
prior of changing medication
Where can I find further support and resources?
RVC Pet Epilepsy Tracker is free to download
and available on
RVC's Canine Epilepsy Research Facebook Page
can keep you up to date with new research and studies in this area,
A Veterinary Neurology specialist can help you to help your pet
with epilepsy. In Europe, ECVN accredited neurologists can be found
and in the US, ACVIM accredited neurologists can be found
For more information on canine epilepsy, the
International Veterinary Epilepsy Task Force
(IVETF) have come together to set out a unified and
standardized set of guidelines for the research, diagnosis
of canine and feline epilepsy for the first time ever in veterinary
medicine. Seven consensus statements from the group have recently
been published, freely available
The Royal Veterinary College have recently published a review
paper on the impact of epilepsy on canine quality of life,
accompanied by a free to access podcast
This article was written by Dr Rowena Packer and Professor
Holger Volk, both from the Royal Veterinary College.
Dr Rowena Packer is a Clinical Investigations
Postdoctoral Researcher at the Royal Veterinary College. Her
current research focuses on the treatment of canine epilepsy and
its impact on canine behaviour and welfare.
Professor Holger Volk is Clinical Director of
the RVC Small Animal Referral Hospital and Professor of Veterinary
Neurology and Neurosurgery at the Royal Veterinary College. His
main research interests are Chiari-like malformation and
syringomyelia and the treatment of canine and feline epilepsy.