CANINE SEIZURES - OVERVIEW,
CAUSES AND TREATMENTS
SEIZURES: THEIR CAUSES
What is Canine Epilepsy?
Epilepsy is a chronic condition characterized by recurrent seizures. Although seizures are always abnormal events, not
all seizures in dogs are caused by canine epilepsy.
Epilepsy is a disorder of the brain where abnormal electrical activity triggers further
uncoordinated nerve transmission. This
uncoordinated and haphazard nerve tissue activity scrambles messages to the muscles of
your dog's body and the coordinated use of the muscles is then inhibited.
are many causes of chronic recurrent seizures in dogs, canine epilepsy is not a specific
disease or even a single syndrome, but rather a diverse category of disorders. Canine Epilepsy is broadly divided into idiopathic
and symptomatic disorders. Idiopathic
Epilepsy, also called primary epilepsy, means that there is no identifiable brain
abnormality other than seizures. Symptomatic
epilepsy (also called secondary epilepsy) is seizures that are the consequence of an
identifiable lesion or other specific cause.
Most dogs with idiopathic epilepsy
suffer their first seizure between the ages of one and five years of age. A genetic
basis for idiopathic epilepsy is strongly suspected in several breeds including the
Beagle, Belgian Tervuren, Keeshond,
Dachshund, British Alsatian, Labrador Retriever, Golden Retriever and Collie.
Idiopathic canine epilepsy may have an inherited basis in other breeds also.
a beloved dog in the throes of a grand mal seizure is one of the most terrifying scenes
you can witness. A seizure refers to the
involuntary contraction of muscles. The
seizure is caused by an electrical storm in the brain.
Seizures can be broken into two types, generalized and partial. In a generalized seizure, the electrical storm
appears everywhere at once. In a partial
seizure, the abnormal electrical impulses begin in a small area of the brain.
tonic-clonic (formerly called grand mal) seizure: The
seizure begins with contraction of all skeletal muscles and loss of consciousness. The dog
usually falls to his side with the legs stretched out and the head back. This is the tonic portion of the seizure. Sometimes he will vocalize or have facial
twitching. Vocalizations are involuntary and
do not indicate pain. Often the dog will
drool excessively, urinate, defecate or eliminate his anal glands. The tonic portion of the seizure is usually very
brief and gives way to the clonic phase of the seizure.
Once the clonic phase begins the dog will have rhythmic movements. Typically this consists of clamping the jaws and
jerking or running movements of the legs.
seizure, the dog may lay motionless for a brief period.
Eventually he will get up on his feet and may appear to be perfectly normal, but
typically will show signs of post ictal behavior. These
signs may include blindness, disorientation, pacing or running about the house bumping
into things. The post-ictal behavior can last
anywhere from hours to days after a seizure.
generalized seizures follow this pattern. Another
type of generalized seizure is the tonic seizure, in which motor activity consists only of
generalized muscle rigidity without the clonic phase.
Less common are clonic seizures where there is no tonic phase and some dogs suffer
milder generalized tonic-clonic seizures in which consciousness is maintained.
seizures: Partial seizures are
also called focal seizures and as the name indicates, the electrical storm is affecting
only a part of the brain. A partial seizure
may stay localized or it may expand to the whole brain and cause a tonic-clonic seizure. Because the seizure starts in only a part of the
brain, an underlying disease or injury is highly suspected.
A partial seizure may remain localized or spread to other parts of the cerebral
cortex producing a sequential involvement of other body parts.
seizures are classified as simple focal seizures when consciousness is preserved and as
complex focal seizures when consciousness is altered.
Any portion of the body may be involved during a focal seizure depending on the
region of the brain affected.
In a simple
partial seizure, the area of the brain that is affected is the area that controls
movement. Usually the face is affected,
resulting in twitching or blinking. This is
usually limited to one side of the face. If
the seizure spreads, other parts of the body on that same side will be affected. The dog is usually alert and aware of his
partial seizure will originate in the area of the brain that controls behavior and is
sometimes called a psychomotor seizure. During
this type of seizure, a dogs consciousness is altered and he may exhibit bizarre
behavior such as unprovoked aggression or extreme irrational fear. He may run uncontrollably, engage in senseless,
repetitive behavior or have fly-snapping episodes where he appears to be biting at
imaginary flies around his head.
Cash WC, Blauch BS: Jaw snapping
syndrome in eight dogs. JAVMS 175:179, 1979
Parent JM Seizures, Small animal medicine 735:741, 1991
Thomas WB: Idiopathic Epilepsy in Dogs. Vet Clinics of N. Amer. Small Animal Practice
SEIZURES: THEIR CAUSES
Seizures are the
result of muscle responses to an abnormal nerve-signal burst from the brain.
They are a symptom of an underlying neurological dysfunction. Toxic substances,
metabolic or electrolyte abnormalities and/or imbalances cause an uncoordinated
firing of neurons in the cerebrum of the brain, creating seizures from mild
"petit mal" to severe "grand mal."
Stages of seizures:
There are four basic stages to a seizure:
~ The Prodome: may precede the seizure by hours
or days. It is characterized by changes in mood
~ The Aura: signals the start of a seizure. Nervousness, whining, trembling, salivation,
affection, wandering, restlessness, hiding and apprehension are all signals.
~ The Ictus: the actual seizure. A period of intense physical activity usually
lasting 45 seconds to 3 minutes. The dog may
lose consciousness and fall to the ground. There may be teeth gnashing, frantic
thrashing of limbs, excessive drooling, vocalizing, paddling of feet,
uncontrollable urination and defecation.
~ The Post Ictus: after the seizure the dog may
pace endlessly, appear blind and deaf and eat or drink excessively.
The cause can be anything
that disrupts normal brain circuitry:
~ Idiopathic Epilepsy, meaning "no known cause"
and possibly inherited. This is also referred to
as Primary Epilepsy. Check history or pedigree and make sure your
veterinarian has looked for possible underlying factors. Seizures
caused by underlying factors are referred to as Secondary Epilepsy.
~ Congenital hypoglycemia (low blood sugar)
~ Hypothyroidism (low thyroid function)
~ Infections causing brain damage (such as canine
~ Ingestion of toxins (such as lead paint chips,
~ Brain tumors
~ Portosystemic shunts (improperly routed intestinal
blood vessels bypass the liver - one of the body's
important waste-product detoxifiers)
Types of Seizures:
~ Mild (Petit Mal) can be a simple as momentarily
staring into space or upward eye movement.
~ Moderate (Grand Mal) occurs when the dog falls down,
loses consciousness and extends its limbs rigidly. Paddling
of limbs, salivation followed by possible loss of control of bladder and bowels
and vocalization (blood curdling scream) may follow. This
may occur for 1-3 minutes and is most often followed by a period of
restlessness, pacing, bumping into objects and loss of balance. Post Ictal
period: The dog is conscious but may appear
deaf, blind and disoriented. Great care must be
taken to prevent the dog from injuring itself at this time.
~ Status Epilepticus can occur as one continuous
seizure lasting 10 minutes or more or as a series of multiple seizures in a
short time with no period of normal consciousness intervening.
This may be life threatening.
~ Cluster Seizures are multiple seizures within a 24
hour period time. This may also be life
threatening. It is often difficult to
distinguish between the two types and veterinarian assistance is imperative. Rectal Valium is extremely useful in breaking
cluster seizures. Please see information
regarding this on our website at these links:
Home Treatment with Rectal Diazepam
and Home Treatment with Rectal and
~ To Reduce Post Ictus
Pacing: As soon as your dog has regained
consciousness and can safely eat, feeding a small
Hãagen Dazs vanilla ice cream (a teaspoon for small dogs; a
tablespoon for medium dogs; two tablespoons for large dogs) can restore normal
blood sugar levels. A seizure may drop blood
sugar levels and low blood sugar levels can cause more seizures. A seizure to your dog is equal to your running
the Boston Marathon so you will need to replace lost energy by feeding a full
meal after the ice cream and then giving a couple of handfuls
of kibble or pasta or rice with a little butter every hour. Feeding
a small amount of carbohydrates every hour will keep blood sugar levels stable. It is important to remember that your dog will
be ravenously hungry so you will need to feed very small amounts at a time
either with your fingers or in a bowl so they do not inhale the food and cause
aspiration pneumonia. Watch your fingers as you
feed them - when dogs are this hungry and recovering from seizures, they can
bite you without ever realizing it.
The use of Bachs Flower Essence Rescue Remedy®
(found in many health
food stores) has been found to be extremely useful in some
cases when given at this time. Simply put four
drops of the Essence into the dog's mouth after the seizure has finished.
Using these suggestions, the post ictal time and severity
will be reduced considerably in many
(listed by trade and generic name):
~ Phenobarbital (abbreviated pb or
~ Potassium Bromide (abbreviated
~ Phenobarbital & Potassium Bromide
~ Valium (diazepam)
~ Dilantin (phenytoin)
~ Neurontin (gabapentin)
Most dogs can be controlled by using Phenobarbital or Phenobarbital and
potassium bromide. Potassium bromide is
used alone if the dog's liver has become damaged by Phenobarbital. (IMPORTANT:
avoid liver damage dogs on Phenobarbital you will need to have a chemistry panel
done every three to four months with the following tests: ALT (SGPT); GGT;
and Alkaline Phosphatase. If any of these levels are more than slightly
elevated your dog will also need either a urine bile acid or a pre and post-meal
bile acid testing to determine how the liver is functioning. If caught very
early, liver damage can be reversible.
and potassium bromide are available by prescription in pill, capsule, and liquid
form. Primadone, once commonly used, metabolizes to Phenobarbital in the liver;
treatment it can also cause liver damage. Valium, injectable administered
rectally and oral tablets, are a good choice to halt a cluster seizure or
interrupt status epilepticus. Dilantin is
currently not recommended for use. Gabapentin
is a newer drug being used for humans. It does offer exciting possibilities for
dogs as it is only partially metabolized by the liver. At
present it is very costly to use at around $250.00 a month; however, with the
few dogs that have used it, the results have been very positive.
plays an important role in the management of Canine Epilepsy.
It is very important to feed a kibble that is preservative-free. Preservatives such as ethoxyquin,
BHT, and BHA should be avoided as they can cause seizures. Many
"supermarket" foods are loaded with chemical dyes and preservatives.
Buy a high quality kibble made from "human grade" ingredients or
better yet, cook for your dog. Many recipes can
be found in Dr. Pitcairn's Complete Guide to Natural Health for Dogs and Cats. PLEASE NOTE: If
your dog is taking potassium bromide,
be very careful when you switch dog foods. Try
to make sure the sodium content is the same as the previous food.
Change over very slowly, whether it is the same sodium content or
different, so that the absorption rate of the potassium
bromide remains constant.
SUSAN WYNN, DVM, on the
canine diet: "Dogs evolved from Canis
lupis - the wolf. Wolves eat caribou or the
like, but if they are forced, they will eat smaller game (rarely). They have been observed to graze on grass, eat
berries, etc, but only when they need to. This
is our lesson in canine nutrition - they are omnivores who do well with fresh
meat, the vegetation they get in a caribou stomach (which is mostly green,
unless the beast is eating from baited fields), and a smattering of other stuff
if they are hungry.
"Food companies have, in the main, revolutionized pet
nutrition by eliminating major nutritional deficiencies and providing optimal
nutrition for the average pet. Our concern,
however, is not for the average pet. It is for
the sick pet. If epileptic animals have a
disease with even a small nutritional component, wouldn't we want to deal with
it? Is your epileptic animal showing other signs
of allergies? If s/he is chewing feet,
scratching ears, having anal gland problems, vomiting bile seasonally, etc., one
may want to consider dietary changes, including hypoallergenic diets, if
"I think that the main benefit of feeding real food -
meat (raw or cooked) raw or steamed veggies, cooked grains - is to provide stuff
that is killed in the kibble extrusion process. If
you or I were to eat a diet of Wheaties, yogurt, VegAll, and Spam day after day
for 20 years, would this be enough? I don't
know, but it makes me uncomfortable. I think our
pets need a more varied diet and a fresher one than we can give them with
commercial kibble. So I do recommend
supplementing pet food with lean meat and vegetables."
It is important to keep your epileptic dog as free from chemical pollution as
possible. Think about the environment your dog is living in.
Do you use chemical
sprays on your lawn? Dogs will sometimes seize only when the lawn is sprayed for
weeds. How about the cleaner you use for the floor?
Some dogs have been known to
seize after the floor has been washed with a pine-scented cleaner. There are
many things that can lower a dog's seizure threshold. Keep a diary of your dog's
seizures. Note anything you have done or anything that the dog could have
in contact with which could have contributed to seizure. It is also a
noted phenomenon that some dogs have seizures around the full moon.
Vaccinations can lower a dog's seizure threshold and trigger a seizure. If you
feel that this is the case for your dog, ask the vet to split the shots and give
them separately. Also ask for the rabies vaccine to be given 2 weeks later. Ask
your vet if he/she knows about the new three-year protocol being used now by
Carson, Joanne, Ph.D.
Cash WC, Blauch BS:
Jaw snapping syndrome in eight dogs. JAVMS 175:179, 1979
Dodds W.J., Donoghue S. Interactions of clinical nutrition with genetics.
Chapter 8. In: The Waltham Book of Clinical Nutrition of
the Dog and Cat. Pergamon Press Ltd., Oxford, 1993 (In Press)
Parent JM Seizures, Small animal medicine 735:741, 1991
Thomas WB: Idiopathic Epilepsy in Dogs. Vet Clinics of N. Amer. Small Animal
Practice 183:206, 2000
goal in treating canine epilepsy is to restore a normal life for you and your epileptic
dog through complete control of seizures with no side effects. However this is
frequently not possible and a more realistic goal would be to reduce the frequency and
severity of the seizures without creating unacceptable side effects from the medications
given. Usually even a well-controlled dog will have an occasional seizure.
right medication or combination of medications takes patience. Unfortunately what
works for one epileptic dog may not work for another. Medications need to be
individualized to each specific dog's needs and this often requires trial and error to
find the right medication and dose.
WHEN TO START
If your dog
has a single seizure or infrequent seizures medication is generally not required.
However, one study does suggest that dogs treated with medication early in the course of
epilepsy have better long term control of their seizures, compared to dogs that are
allowed to have many seizures before anti-seizure medication is started. The
decision to begin medication should be made between the owner and veterinarian, taking
into consideration the risks of not treating the disease against the risk of side effects
of the medication.
THE CHOICE OF
or Potassium Bromide is the initial treatment of choice for patients that require drug
therapy. Please see the medications portion of
our web site for more information on the drugs available to treat canine epilepsy.
many reasons why treatments can fail. The biggest ones are the owners' lack of
proper administration of the medications, errors in drug therapy and improper
diagnosis. Referral to a neurologist should be considered if control is not
achieved within three months or if the diagnosis is uncertain.