Seizures in dogs and cats

Dogs and cats are occasionally affected by seizures (also known as fits or convulsions) and, understandably, these can be really terrifying for the inexperienced owner. For this reason, it's a good idea to have some basic knowledge about what you are potentially dealing with. This article gives an overview of the nature and causes of seizures and provides some advice about what to do if your pet is affected.

What are seizures?

Seizures are the physical result of abnormal electrical activity within the brain and broadly fall into two groups:

Generalised seizures

As the name suggests, these affect the whole body and are the most common seizures in dogs. The most prevalent are the 'tonic-clonic' seizures, which tend to be most familiar to people and are normally accompanied by loss of consciousness. They are comprised of a 'tonic' phase, during which increased muscle tone causes the animal to fall to its side, and a 'clonic' phase, consisting of intense muscle jerking. The sequence of events that makes up a generalised tonic-clonic seizure does vary considerably between animals, but follows a similar basic pattern: the prodromal stage, followed by the ictus, then the postictal stage.

• The prodromal stage consists of a behavioural change and varies greatly in duration, from a matter of minutes to days. The behavioural change may be too subtle to notice; alternatively the animal may display obvious symptoms such as restlessness, vocalisation, hyperactivity, hiding, salivation or vomiting.
• The ictus is the 'main' seizure. Typically, there is a sudden increase in tone of all the muscles and the animal loses consciousness. The pupils of the eyes usually dilate and there may be violent jaw movements, excessive salivation and involuntary urination or defecation. The animal may paddle the legs as if trying to walk or run. This phase can last from just a few seconds to several minutes.
• In the postictal stage the animal becomes motionless or sleepy. It normally gets up after a few seconds or minutes, but tends to be disorientated and unresponsive. It may wander around restlessly or appear blind and deaf. As it starts to return to normal, it may become extremely hungry or thirsty. The length of this stage is, again, highly variable - from just a few seconds to several days.

Partial (or focal) seizures

These affect a localised area rather than the whole body and are relatively common in cats. They may be 'simple', in which there is no loss of consciousness, with relatively mild signs such as muscle twitching occurring. Alternatively, 'complex' partial seizures may occur, in which consciousness is impaired. It can be quite difficult to recognise these as actual seizures and they may be confused with something else. Symptoms can include confusion, restlessness, dilation of the pupils or twitching of the facial muscles. Behavioural changes are often seen - for example, barking or howling, activity such as licking or chewing, or aggressive or defensive behaviour. Episodes may last for several hours. There is also usually a noticeable 'prodromal-ictal-postictal' pattern to these. Partial seizures may progress to generalised seizures.

What is epilepsy?

The term 'epilepsy' simply relates to recurrent seizures.

What causes seizures/epilepsy?

There are many potential causes of seizures in dogs and cats and these are broadly divided into two groups: those that originate within the brain ('intracranial' causes) and those that originate outside the brain ('extracranial' causes). Intracranial causes include progressive disorders such as tumours (which are, thankfully, relatively uncommon) and non-progressive disorders such as inherited or 'idiopathic' epilepsy. 'Idiopathic' is a fancy term used by vets and doctors, basically meaning that we don't know what causes the condition. Idiopathic epilepsy is one of the commonest 'causes' of seizures in dogs.Extracranial causes include metabolic disorders, such as hypoglycaemia (low blood glucose) and kidney failure, hyperthermia (overheating) and various poisons, such as chocolate.

What should I do if my pet has a seizure?

• First of all, try not to panic. It will be in your pet's best interests if you can keep calm and in control of the situation.
• Try to take note of the duration of the seizure and symptoms displayed as this information will be very useful to your vet.
• In most cases, your pet will have lost consciousness and won't be in control of what he/she is doing, so don't put your hand anywhere near the mouth as you might accidentally be bitten.
• If necessary, move your pet to a safe area (for example, away from the top of the stairs, or from the sofa to the floor) and remove any nearby objects that could cause an injury. Otherwise, leave them be - don't try to restrain your pet.
• Dimming the lights and avoiding loud noises (such as the TV) can be helpful as this reduces stimulation of the brain.
• Be aware that sometimes even the nicest dog will instinctively attack another canine that is seizuring, so keep an eye on your other dogs and remove them from the room, if necessary.
• In the case of tonic-clonic seizures, your pet should quickly come out of the ictal part of the seizure and enter the post-ictal phase. When this happens, talk to him/her in a quiet, reassuring voice as this can help alleviate disorientation.
• Within reason, let your pet behave as they wish during the post-ictal phase but, of course, keep an eye on him/her and make sure your pet doesn't do anything to harm him/herself.
• After a full assessment, your vet may prescribe some medication for you to administer when your pet has a seizure.

When should I take my pet to see a vet?

• It's advisable to take all puppies and kittens to the vet immediately, as in young animals seizures can be caused by such life-threatening conditions as hypoglycaemia (a dangerously low blood sugar level).
• If your pet's seizure has lasted over 5 minutes or he/she has had 3 or more seizures within the last 24 hours (a condition known as 'status epilepticus') then you should take him/her to the vet immediately. Prolonged seizures can cause brain damage.
• If your pet has had an isolated, short duration (less than 5 minutes) seizure for the first time and is otherwise well with no other symptoms, then it's wise to wait for the post-ictal phase to pass and then book an appointment with your vet.
• Once your vet has assessed your pet then they can advise you accordingly about what to do in the event of future seizures.

What will my vet do?

This will, of course, depend on the individual case. If your pet is in status epilepticus then your vet will need to give medications to try to stop the seizuring as quickly as possible and then investigate the underlying cause. If your pet is no longer having a seizure, your vet is likely to recommend blood tests and other diagnostic tests (possibly ultrasound or x-rays, for example), to rule out the most likely underlying cause. If an underlying cause is identified then treatment is normally targeted at correcting or managing this cause. For example, surgery may be recommended to correct a portosystemic shunt (this is a condition in which blood bypasses the liver, thus leading to a build-up of toxins which results in seizures). Equally, intravenous fluid therapy may be advised to manage cases of poisoning.If no underlying cause is identified then your pet may have 'idiopathic' epilepsy. Normally, an isolated seizure isn't sufficient to warrant treatment but, if there are recurrent seizures, then ongoing medication may be beneficial to reduce the frequency and severity. There are pros and cons of long-term seizure medication and your vet will be able to discuss these with you.