Seizures In Dogs And Cats
What is a seizure?
A seizure is a complex series of events that originate in the motor cortex, or front portion, of the brain. A group of neurones (nerve cells) in this part of the brain suddenly produce an excessive amount of electrical activity which spreads through surrounding areas of the brain. This activity can be so pronounced that the individual may lose consciousness and control of bodily movements and functions. Seizures may last from several seconds to many minutes. Convulsions usually involve collapse, muscle convulsions (including padding of the legs and champing of the jaw) and extension of the neck. Convulsions may occasionally include loss of bowel and bladder control and vocalisation (howling). Following a convulsion comes a period of relaxation of the body followed by disorientation and drowsiness (occasionally aggression) and eventually recovery.
A seizure, fit or convulsion can cause an owner a considerable amount of concern at the time that they happen. Sometimes it may only occur a couple of times in the animal’s life and causes no further problem and other times it may be a sign of another disease condition in the body. For a Veterinarian to be able to distinguish what is happening to the animal he will need to examine the animal and do some tests.
What causes a fit?
There are many causes of fits. We will start by breaking them into two groups, the first group are extra-cranial, or causes that do not start from within the brain but from the rest of the body. An example would be when the fit is caused because the animal has diabetes or has liver damage. The second group are intra-cranial causes, or ones that start from within the brain only. We will start looking for extra-cranial causes first as these are more easily identified than intra-cranial causes.
General Plan of Action!
Firstly, if this is your pet’s first fit, we will start with a normal clinical examination and, if nothing is apparent, we will most likely do some screening blood tests. As one of the tests we may need is a fasting blood glucose level we may need to keep your animal in overnight.
If the results from these tests do not reveal anything wrong then we start to investigate if there are any intra-cranial causes, for example meningitis or brain tumours. This is done by doing a CSF tap and a CT scan or MRI of the brain. For both these tests your animal needs to be anaesthetised. If there is nothing revealed from these tests then it is most likely that your animal has a form of epilepsy.
What can be done?
Most cases of epilepsy can be treated with a good outcome provided treatment is started early enough. This is because, as the group of nerve cells that fire off the fit do it more often, the brain learns the process and it is easier for the impulses to travel throughout the rest of the brain. There are also those cases that are unresponsive to treatment and will fit more frequently as time goes by and more cell groups learn how to start a seizure.
This handout is not the full story of seizures. It is only meant as a guide for owners who are faced with an animal that is fitting for the first time and who have had a full discussion with the Veterinarian handling your case. As every animal is different, so is every case of the fitting animal and the management of each case will be slightly different.