Diseases of the Brain

Seizures and Epilepsy in dogs

The central nervous system is very complicated and sensitive to biochemical, photon, hormonal, and electrical energy.  Also pressure, centrifugal and other forces. 
And for all I know, radio waves, cell phone communication waves, sound waves and so forth.  Any of these forces, in excess, could potentially cause the firing of too many nerons at a time leading to seizures in a susceptible animal.  Acid rock music is probably especially dangerous.

Introduction:  Epilepsy and Seizures.

Epilepsy was originally a word that meant seizures of unknown cause.  Evil spirits were often blamed.  Exorcists were called upon for healing. 

Today, we have a much better idea about the causes and control of seizures, but in truth, there's still a lot we don't yet understand. 

Seizures are a fairly common problem in dogs but luckily, most dogs with seizures lead a long and normal life. 

And while the seizures can be frightening to the dog..."whoa, what the"...apparently they are non- painful.

The actual seizure is usually quite short 20-180 seconds, but there is usually a much longer period where the patient is a little shaken called the aura.  And sometimes the seizures can be multiple.

Often the seizures are instigated by an over excited brain.  Often there's a know trigger such as thunderstorm anxiety or other fears.

Seizures can be due to pressure from brain tumors and we know there can be a genetic basis for seizures.

If your dog or cat has had a seizure, here's what we recommend:

1.  A good exam.  This is to make sure there is no obvious cause such as poisoning, anemia, high fever, a tooth or ear infection, abnormalities of the eyes, lymph nodes, heart, or lungs.

2.  Blood work:  to test for pancreatitis, diabetes, low blood sugar, thyroid imbalances, electrolyte imbalances,  internal infections, anemias, protein problems and so forth.

If the history warrants, it may be appropriate to test for leukemia, Feline AIDS, heartworm disease, Lymes disease, & erlichia.  These are all simple blood tests available at most all veterinary clinics.

3.  Parasitism can end up causing seizures so a fecal test may be appropriate.

4. Urinalysis: To check for sugar, protein, ketones, and general health. 

It all comes down to general health; if your body is diseased, fighting off infections or parasites, is malnurished, or there are hormone imbalances ... any of these things may be the underlying cause of seizures.

5. Radiographs: Poor perfusion of blood and oxygen to the brain due to heart or lung disease can certainly cause seizures.  Chest radiographs ... especially in cats ... are one the best ways to diagnois heart and lung diseases .... so chest radiographs may be recommended.

Radiographs of the brain may be recommended to look for signs of inflammation, tumors, and skull injuries, but radiographs often fail to detect brain tumors because ... if present ... they aren't dense enough to look different from the nearby healthy brain tissue.

6.  Other imaging techniques: MRI's and Cat Scans of the brain are the ultimate in ruling out brain lesions and masses.  But such technology is typically only available at veterinary specialty practices and costs over $1000


Step One:  Treatment of any other health problems that are detected if any.

Step Two:  Control of the seizures.  As a rule of thumb, we recommend seizure control IF there is more than 1 seizure a month or if they are very violent .... but we often elect NOT to treat.

Whether or not to treat ... and which of the several seizure control medications are chosen is something you should discuss with your veterinarian. I usually use a combination of phenobarbital, zenisamide, diazepam but sometimes other drug combinatons work best.

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Diseases and Problems of the Brain, Seizures

Granulomatous meningo-

Diskospondylitis (Intervertebral Disk Disease)  Also wobbler's syndrome

Notice the open mouth and pupil dilation.  This pup is having a seizure.
Seizures can be caused by anything that over excites, over stimulates, or causes irritation or pressure to the brain.

Any disease that changes the chemistry, blood flow, or supply of sugars, nutrients, or oxygen to the brain can cause seizures.

We know that some dogs are genetically prone to seizures.

We know that some dogs have seizures from extreme anxiety over things like thunderstorms but other dogs have seizures when they are calmly asleep.

With some seizure patients we find a probable cause such as anemia, or poisoning, or parasites, or diabetes... but the most common cause of seizures is idiopathic which is a wonderful medical term for " don't have a clue".

Epilepsy is the name of the disease when a patient has recurring bouts of seizures and we can't detect any underlying cause.

In past centuries, people and animals with epilepsy were often thought to have evil spirits in them and would be shunned, killed, or undergo exorcism rites.

Perhaps in the not too distant future ... we'll have a better understanding of what causes the nervous system to go "haywire" every once in a while.

I get a lot of emails every day.  For lots of reasons, I can't answer specific medical questions by email ... although this website is my way of sharing my general knowledge and love of veterinary medicine.

Here's a couple of typical emails ...

hello Dr Ross. We have just had our 5 yo German Shepherd "put to sleep" and are devastated.

He had a  very slight "wonky" back leg on Saturday,   Monday PM he fainted and was rushed to the Overnight clinic. 

Brought him home Tuesday AM. Our vet said to bring him in the next day for  assessment.
By Wednesday AM , when we awoke, he had lost the use of  both hind legs. We were at the vet by 7.30 and by then hs front legs were going also.

By lunchtime (who could eat?) they rang to say it was either Encephalitis, Meningitis or a tumor.  As they spoke the results came through...a brain tumor. We agreed to have him put to sleep, and the vet said OK, as he is "shutting down" as we speak.

The only other symptom was he  was very   sensitive when touched..If one went to touch him, his skin jumped like a horse, when a fly lands on it.
I strongly suspect a Glioma, after reading vet things on the computer. My point in writing this is to show how quickly it took hold. He enjoyed his food and was playing ball, then 36 hour later he was dead!

Thanks, Bye now, A.Y. Melbourne ,Australia

Dr. Ross,
I am emailing you from a rural community in Texas.  We live on a farm and sometimes have visiting wildlife. 

In past years, we have had a few "resident skunks." 

We never offer food to them, but instead leave them alone to do their special job of eating grubs and crickets.  This works out well for all of us. 

Last evening, however, we had a bit of a concern.  My husband called me to come outside and look at a skunk that was not acting quite right. 

It was a male adult, and we noticed a long scar over the right shoulder extending down the leg, as if from an old injury. 

It just looked like the hair had never grown back.  I stayed out there and watched it for probably 30-45 minutes.
During that time, I witnessed what appeared to be at least 3 grand mal seizures. 

The skunk would fall on its side, paddle its legs, grimace and chatter its teeth, and throw its head all the way back. 

The last seizure lasted about 10-15 seconds, maybe longer.  Between seizures, the poor skunk would right itself, take its paws and clean the sand out of its nose, snort, lick its lips and even scratch itself, then stagger around. 

After the last seizure, we continued to watch it and to our amazement it got to walking better & faster and began holding its tail in a healthier manner. 

It walked around the yard for a while and looked perfectly normal, then went on its way.  I wondered if it ate something that made it sick or stumbled across some pesticide of some sort. 

I even entertained the thought that it may have been hit by a car in the past (hence the scar) and might have had some brain damage. 

We rarely use pesticides because we have 9 cats and are very particular of what goes on in their lives and surroundings. 

Oh, by the way, the skunk did not act like it would try to spray us.  I have heard that is a sign of a sick skunk, but we have had several that have visited and stayed awhile and none of them ever spray at us because we give them plenty of space and are careful not to alarm them. 

You know, I really think they get a bad rap in general, but we think they are wonderful "grub eating machines".  I would like your input on these seizures, if you don't mind emailing me back.

This is a good time to remind people that SKUNKS are a major carrier of rabies and there is a fairly good chance that the skunk described in the letter above is suffering from rabies.

Another article about Seizures from the 
Client Information Series by Michael Podell

The diagnosis and treatment of seizure disorders in small animals are similar in many respects to the diagnosis and treatment of other ailments: a historical problem arises, a proper diagnosis is made to confirm the condition, and therapy is started to treat the underlying disease and/or signs of the disease.

In seizure disorders, however, unlike other diseases, a long period of normal activity may occur between the seizure events.

Even during these normal periods, serious conditions may still be present as the cause of the seizures. Knowing which animals are at the highest risk for such problems is helpful in planning the proper tests and treatment.

First, your veterinarian wants to be sure that an epileptic seizure has occurred and, if so, the seizure type(s) manifested.

An epileptic seizure is the clinical sign of excessive, abnormal activity in the brain and the clinical features can be separated into three components.

The aura is the initial manifestation of a seizure. During this time period, which can last from minutes to hours, animals can exhibit recurrent pacing or licking, excessive or unusual salivation or vomiting, and/or even unusual psychic events such as excessive barking or increased or decreased attention seeking. Some owners even report that they know their dog is going to have a seizure days in advance by changes in the animal's behavior.

The ictal period is the actual seizure event, manifested by involuntary muscle tone or movement and/or abnormal sensations or behavior, usually lasting from seconds to minutes.

After the ictal event is the postictal period. During this time, an animal can exhibit unusual behavior, disorientation, inappropriate bowel or bladder activity, excessive or depressed thirst and appetite, and actual neurologic problems, such as weakness and blindness.

Seizure types can be classified into two major categories:

Partial and Generalized.

Partial seizures are the result of a focal abnormal electrical event in the brain. This seizure type is associated with a higher prevalence of focal disease, such as a tumor.

Animals with simple partial seizures have a sudden change in activity without any change in awareness, such as twitching of facial muscles.

Animals with complex partial seizures often show bizarre behavioral activity, such as "fly-chasing" behavior patterns.

Generalized seizures are either convulsive ("grand mal") or nonconvulsive ("petit mal") seizures. Generalized convulsive seizures are by far the most common seizure type seen in animals and are characterized by impaired consciousness coupled with symmetric stiffening, paddling, or even loss of movement of the limb muscles.

The major form of nonconvulsive seizure is the "absence" variety, manifested as a "spacing-out" episode.

The severity of the seizure does not necessarily match the cause, as dogs with brain tumors may have mild partial seizures and dogs with primary epilepsy may have severe generalized seizures.

The second level of assessment is the diagnosis of the cause of the seizures. Just as a cough signals a problem in the airway, a seizure tells us there is a problem in the brain, but not the cause.

The goals of a diagnostic evaluation are to determine the underlying cause, evaluate the chance for recurrence, and establish whether medication is necessary for treatment.

Primary epileptic seizure (PES) is diagnosed if no underlying cause of the seizure can be identified (idiopathic). This term is often reserved for inherited epilepsy in people, but the genetic component of epilepsy is difficult to determine in many animals.

Breed-related inherited epilepsy in the dog has been documented in Beagle, Belgian Tervuren, keeshond, dachshund, and Siberian husky dogs. Other breeds with a high prevalence of an inherited component of their seizures are German shepherd, border collie, Irish setter, and golden retriever dogs.

A diagnosis of PES is most common in large breed dogs 1 to 5 years of age and/or when the interval between the first and the second seizure event is long (> 4 weeks).

Secondary epileptic seizure (SES) is the direct result of an abnormal brain structure. The conditions involved include developmental brain problems, inflammation, tumors, or strokes. An animal is categorized as having epilepsy if recurrent PES or SES is diagnosed, indicating the presence of a chronic brain disorder.

Reactive epileptic seizure (RES) is a reaction of the normal brain to transient systemic insults or physiologic stresses. A patient with recurring RES is not defined as having epilepsy, as there is not a primary chronic brain disorder underlying the seizure activity.

An underlying identifiable cause (SES or RES) of the seizures is suspected in dogs that have an initial seizure when they are younger than 1 or older than 5 years of age, the initial interval between the first and second seizure events is less than 4 weeks, or a partial seizure is the first observed seizure. Cats, in general, do not suffer as frequently from seizures as dogs.

When cats have seizures, there is a high likelihood that an underlying problem in the brain (SES) is present, such as inflammation, stroke, or tumor.

Maintaining a seizure-free status without unacceptable adverse effects is the ultimate goal of antiepileptic drug (AED) therapy. This optimal balance is achieved in less than half of epileptic people and, probably, just as many dogs.

Before starting AED treatment, owners and veterinarians should have a realistic idea of what to expect over the course of therapy. First and foremost is that seizure control does not equal elimination.

Decreasing the number and severity of seizures and postictal complications, while increasing the time period between seizures, is a realistic goal.

Once treatment is started, you should realize that there is a daily treatment regimen, re-evaluations are required, and there is a potential for emergency situations to arise, along with the inherent risks of the drug.

The decision to start AED therapy is based on the underlying cause, seizure type and frequency, and postictal effects. An acceptable AED is one that can be given two to three times per day, has documentable benefit, is well tolerated, and has few side effects.

The two AEDs most widely used in the dog and cat are phenobarbital and potassium bromide.

Bromide has the benefit of a reduced chance of liver toxicity but may not be as effective as phenobarbital for stopping all types of seizures or work as quickly.

Periodic measurements of the amount of drug present in the bloodstream are necessary to determine that an acceptable level of medication is present.

At the same time, blood tests to evaluate liver function may be necessary. These periodic evaluations are important in trying to maximize the benefit of drug therapy while monitoring for early detection of possible complications.

Treating each animal as an individual, applying the philosophy that seizure prevention is better than intervention, and consulting your veterinarian to help formulate or revise treatment plans increase chances of success.
This is off subject a little bit, but there are sevice dogs that can sense a seizure coming on in their human companion and know how to go get help.  These service dogs are allowed in restaurants, hotels and so forth now.