Close X

What are Seizures and What Causes Them?

My dog Ozzie has been having what the vet called "grand mal seizures". Blood tests ruled out liver, kidney, etc as the cause. He does...

Dr. Eric Barchas  |  Aug 5th 2008


My dog Ozzie has been having what the
vet called “grand mal seizures”. Blood tests
ruled out liver, kidney, etc as the cause. He
does have a heart murmur. The vet thinks he
either has epilepsy or a brain tumor. He has
prescribed phenobarbital daily. Ozzie
has been taking the medicine for just over a week
and there does seem to be some improvement. He
has not had another seizure and has started to act
more normally. In recent weeks his behavior had
changed. He was not as friendly, more withdrawn,
and would not jump up on the furniture or the bed.
A few weeks ago, I could not keep him off the
furniture. Now he seems to be back to his old
self. Do you think this sounds like epilepsy or
do I need to worry about brain tumors? Ozzie is
almost 7 yrs old and weighs 23 lbs.

Rebecca
Ogden, Utah

Gran mal seizures are very frightening to behold. Pets that suffer these types of seizures lose consciousness and collapse. Their limbs flail wildly. They may urinate or defecate during the event, which usually lasts less than a minute.

A period of irregular behavior may occur before and after seizures. These periods may last just a few minutes, or up to several days. This phenomenon may, or may not, explain Ozzie’s irregular behavior leading up to his seizures.

Seizures occur when an area of the brain develops abnormal electrical activity. This activity spreads to and takes over other areas of the brain. When large portions of the brain are engulfed in abnormal activity, a seizure occurs.

Seizures have many causes. In very young animals, epilepsy is a leading cause.

In animals of any age, metabolic problems such as low blood sugar and liver problems can lead to seizures. As well, animals of any age can suffer from infections or abscesses in the nervous system, or trauma to the head–any of these can cause seizures.

In older animals, brain tumors frequently trigger seizures as well as behavior changes (which, once again, may or may not explain the changes in Ozzie’s behavior leading up to the seizures).

Based upon your description, I cannot tell what is causing Ozzie’s seizures. Your vet took the correct first step by running blood tests to look for metabolic conditions. If you want to know more, the next step is diagnostic imaging: X-rays and ultrasound of the chest (this will also help to assess Ozzie’s heart) and abdomen, followed by MRI scanning of the brain. In many (but not all) cases, these tests lead to a definitive diagnosis.