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The
account accompanying my notes was written by the
owner of a Beardie who does not want to be
identified. Seizures are scary for an owner –
especially the first time – so I wanted to
include a first hand account.
A
seizure is a symptom and not a diagnosis. It is
estimated that about 1% of dogs will experience
a seizure over the course of their life, and
while they are more common in certain breeds
(affecting 15-20% of animals) they are
relatively infrequent in Beardies. A seizure
represents a transient paroxysmal disturbance in
the electrical activity of the gray matter, most
often in the cerebral cortex but sometimes in
the thalamus, hypothalamus or midbrain. The
appearance of the seizure can reflect the area
of the brain affected. It may involve changes
in behavior, consciousness, muscle activity,
sensation or autonomic (unconscious) actions.
Behaviorally seizures can manifest as confusion,
dementia, delirium, rage or fear. Muscular
changes can produce involuntary spasms that can
be rigid (tonic) or jerky (clonic) or result in
limb paddling. The jaw may be locked or the dog
may make chewing, licking or lip smacking
motions. The dog may spin, pace or run if he
remains upright. In humans we know that
seizures are often accompanied by sensory
changes, but these are harder to appreciate in
dogs. Pawing at the face, attacking the tail or
chewing and biting the flanks may indicate
changes in body sensation. Biting at invisible
flies may be a manifestation of visual
hallucination. Increased sensitivity to sounds,
light, and/or touch may be appreciated, as well
as increased sniffing suggesting increased
awareness of smells. Rapid eye movements (nystagmus)
may be noticed along with loss of balance.
Increased salivation along with uncontrolled
urination and defecation represent over-activity
of the autonomic nervous system. Rarely
paroxysmal vomiting and diarrhea will be part of
the seizure.
Seizures are classified as general or
partial/focal and can be mild or severe. In
mild general seizures the dog may appear
confused and have muscle tremors – rippling
skin/shaking. He may seek comfort from his
owner and reassurance may actually curtail the
seizure. Mild seizures can build into severe
ones, however. Electroencephalograms recorded
during mild seizures show symmetrical
alterations in electrical activity, while in
severe ones there is massive electrical
discharge throughout the cortex. Partial
seizures show localized, asymmetrical changes
and the symptoms reflect the part of the brain
affected. In the motor cortex there will be
spasms of the face or limbs on the opposite side
from the brain activity. Partial seizures
affecting the limbic system result in outbursts
of abnormal behavior – frantic running,
aggression, rage and/or hallucinations.
Seizures can have many causes. Recurrent
seizures of no known cause are referred to as
idiopathic epilepsy. This condition is usually
inherited and is usually first seen when the dog
is between one and three years of age. However,
some “idiopathic” epilepsy is likely the result
of trauma to the brain, with seizures starting 6
to 12 months after the injury. In dogs under 9
months of age, seizures are often the result of
congenital problems (hydrocephalus,
lissencephaly, storage disorders, metabolic
disorders, portosystemic shunt); infection
(distemper and other viral diseases, fungal,
protozoal or bacterial encephalitis); toxicity
(lead, organophosphates); trauma; hypoglycemia;
thiamine deficiency. From 9 months onwards
infection, trauma, toxicity, hypoglycemia,
metabolic disorders, and idiopathic epilepsy are
joined as potential causes by
meningoencephalitis, acquired hepatic
encephalopathy (secondary to liver disease); as
well as brain cancer in older animals.
During
a seizure the threshold for excitation in a
number of nerve cells in a region of the brain
is lowered either due to an increase in
excitatory neurotransmitters or reduction in
inhibitory ones. (Neurotransmitters are
chemicals that transmit nervous activity from
nerve to nerve or from nerve to muscle.) The
activity of nerves is also dependent on the
concentrations of potassium, sodium, calcium and
chloride ions within and outside the nerve.
Changes in electrolyte levels can also result in
seizures. The nerve cells at the focus of the
seizure stay excited for a prolonged period and
gradually excite surrounding cells in an
increasingly larger area. This is called
kindling. Other foci of activity can also be
established. Once enough neurons are involved
the seizure will be seen. A typical seizure
often has three phases: the pre-ictal or
prodromal period – sometimes called the aura
(when the dog may realize that a seizure is
coming and react in a characteristic manner),
this can last more than a day; the ictus (the
actual seizure); and the post-ictal phase (which
may include pacing, depression, drinking, eating
or sleeping, but which is characteristic for
each patient) which can continue for several
days. Between seizures most dogs appear totally
normal.
Because most dogs are normal by the time they
see a veterinarian, history is most important in
evaluating seizures. A single seizure is scary
to owner and Beardie, but may never happen
again, so apart from watching to see if there
are more seizures little else needs to be done.
If a dog suddenly starts having multiple
seizures within a week, it suggests active brain
disease and it would be wise to initiate a more
aggressive diagnostic plan. Partial seizures or
partial seizures that generalize suggest a
structural, localized problem – encephalitis,
tumor, injury or stroke. If the owner notices a
characteristic turn of the head, spasms, on one
side of the face or the lifting of one leg
before the seizure it suggests a localized
seizure that has generalized. Asymmetry of the
signs also suggests partial versus generalized
seizures. Partial or mild general seizures can
last over 30 minutes, but partial seizures that
generalize or severe general seizures last less
than five minutes – although it can seem like
hours! A video of the seizure can provide
important diagnostic information. Changes in
behavior and/or gait between seizures indicate
an active disease process in the brain.
A
thorough history will gather information about
the various body systems – respiratory,
gastrointestinal, renal, etc. – which may
indicate a systemic disease altering brain
function. Information on diet; exposure to
toxins and drugs; known traumas; similar signs
in other animals in the same household or in
related animals; current medications can all
provide relevant diagnostic data. The physical
examination should include examination of the
eyes and a complete neurological examination.
Typically, testing would include a complete
blood count, fasting biochemistry profile,
thyroid profile, bile acids, serum lead and/or
cholinesterase levels (if toxicity is
suspected), urinalysis and if neoplasia is
suspected chest and abdominal X-rays.
Hypothyroidism, electrolyte imbalances,
metabolic disorders and/or toxicity must all be
ruled out. If the dog is having frequent
seizures, further testing would include MRI or
CT of the brain, EEG and testing of the
cerebrospinal fluid to find the underlying
cause.
If the
primary cause of the seizures is discovered
treatment is directed at treating this, although
anticonvulsant therapy may be initiated while it
is brought under control, and then gradually
phased out. If a cause cannot be discovered and
seizures occur more frequently than twice a
month, or in clusters, treatment is aimed at
reducing frequency to an acceptable level. The
treatment of all underlying causes is beyond the
scope of this article. The drugs most
frequently used to control seizures are
phenobarbital and/or potassium (occasionally
sodium) bromide. Phenobarbital is the cheapest
and most effective drug, but it is also toxic to
the liver, and because absorption is variable
blood levels must be carefully monitored – the
therapeutic level being close to the lethal
one. Combining the two drugs may allow lower
doses of phenobarbital to be given effectively
and more safely, as bromides have no liver
toxicity. Both drugs – given alone or in
combination – can produce a level of sedation
unacceptable to the owner. However, in general,
either alone or in combination these drugs can
be used safely and effectively to control
seizures. Diazepam is too short acting in dogs
to be of value in preventing seizures, but can
be given intravenously or rectally to quickly
stop cluster seizures (status epilepticus). If
these are unchecked, loss of oxygen can cause
irreparable brain damage. Newer drugs are also
being used to treat some seizures in dogs.
These include gabapentin (Neurontin), zonisamide
(Zonegran) and levetiracetam.
Patients with seizures should be fed a balanced
diet without extra supplementation. They should
avoid chemicals and drugs which could make them
more susceptible to seizures. While clinical
studies are lacking heartworm preventatives
containing ivermectin and flea preventatives
Program and Advantage may lower seizure
threshold and make seizures more difficult to
control. Organophosphate insecticides should be
avoided. Interceptor and Frontline appear to be
safer for patients with seizure disorders.
Acupuncture can be effective in some cases,
including those that resist pharmaceutical
intervention. Valerian root is a traditional
anticonvulsant, which may be beneficial and
could be tried before turning to more
potentially toxic treatments. Milk thistle
might help to protect the liver during
phenobarbital therapy.
Chances are good that you and your Beardie will
never experience a seizure. If you do, try to
stay calm and not panic.
-----------------------------------
The
bumping against the closet doors woke us up at
4:45 am on Tuesday, May 9, 2006. He was having a
generalized seizure. That’s the term they use
now for what we used to call a “grand mal”
seizure. I was terrified. Here was a Beardie
lying there salivating, urinating, paddling, jaw
clenched, breathing as if he were running, but
choking at the same time and I had no idea what
to do. This lasted about a minute. Then he
calmed down and the “cool down” period lasted
another minute with his breathing slowing, heart
rate slowing and wanting to get up. We kept him
lying down until he appeared to be back to
normal. When he did get up he seemed coherent. I
snapped on his leash and rushed him to the
all-night emergency hospital. Of course, the vet
on duty sent me home to monitor him and make
sure he was ok. He was a bit unsettled and
clingy over the course of the morning.
I
called my regular vet the next day and put in a
call to my good friend who is Professor Emeritus
of Veterinary Neurology. She suggested taking
him to a nearby teaching hospital for
superficial neurological tests, as well as blood
work. Everything came back “normal”. Meanwhile,
my friend gave me a “Seizure 101” Cliff Notes
version of canine seizures that night on the
phone.
The
advice was, just wait and see if he has another
one. He recovered just fine. I spent hours
Googling “seizures in dogs” and read mountains
of material. After awhile, the material began to
repeat itself so I felt comfortable that I was
reading the right stuff. And, of course, we
scoured the yard to make sure he had not gotten
into any poison or other chemicals and checked
all of our records for yard spraying. Shoot, we
checked everything we could think of and came up
empty.
Many
things can cause seizures, and many of those we
don’t even know about.
The
next seizure happened in September of that
year…Monday, September 4, 2006, 4:00 am-ish as a
matter of fact. On the advice of my friend, I
keep a log of each seizure, noting day, date,
time of day, duration of seizure, symptoms, and
length of recovery time. This time, the seizure
lasted a little longer and it was stronger.
Evidently, he had thrown up first. In addition
to the above things, he gnashed his teeth and
defecated. His tongue and gums were gray. He had
a secondary seizure that lasted another minute
or so, with more paddling. Afterward, his
emotions were out of whack for at least a couple
of hours. Again, he knew the seizure was coming
on because he had come flying into our bedroom
at the onset. I was calmer because I had been
through this one time before.
This
time I made an appointment with a veterinary
neurologist who suggested we put him on
Potassium Bromide (KBr) to forestall any future
seizures. In addition we had a battery of blood
tests done, an MRI and joint taps, all of which
came back as those of a healthy dog. So, the
decision, give KBr or not? I opted for the
medicine, against my husband’s and, probably,
many others’ wishes. He was on that for a year
and was seizure-free, but the medicine did have
side effects, one of them making him terribly
hungry or having a terribly upset stomach.
During the period he was on that medicine, we
had to barricade the kitchen to keep him from
climbing on the counters trying to find food.
Luckily, the KBr worked fine and did not have to
be paired with Phenobarbital. Three months after
discontinuing the medicine, he had another
seizure.
Same
drill, 5:00 am, came in and jumped on our bed.
This was, yet, worse than the ones he had
before. I reported the seizure to all of his
doctors but opted to wait and see before putting
him back on KBr.
The
next one came on Saturday, May 10, 2008, around
4am. Basically, it was the same as before but
not, quite so bad.
The
latest seizure came Friday, September 5, 2008
around 5:30 am. This one lasted around a minute,
with a secondary seizure or, maybe a cool-down
period of a minute and a half. He woke us up
throwing up, and then he jumped on the bed to
have the seizure.
All we
can do during these is steady him and try to
keep his throat clear (by keeping his head and
neck straight as possible) so he can breathe.
Until the seizures happen more frequently, he
won’t go back on medicine.
If you
notice the dates, you’ll see that 4 of them have
been 2 years apart, almost to the day.
May 9, 2006
May 10, 1008
September 4, 2006
September 5, 2008
December 12, 2007
Aside
from the December seizure (which was 3 months
after going off of his medicine), that tells me
something “otherworldly” is causing them,
something that science has not identified yet.
People will say I’m crazy, that statistically
it’s insignificant, but, to me, it means
something. I don’t know what, but something.
So, we
have decided to live with these until they
become more frequent. I’m going to start
acupuncture treatments and just monitor him,
especially around May and September. During all
of this, he was able to continue herding sheep
but did have to stop agility when he first
started KBr treatment. As the amount of KBr
tapered off, he was able to resume agility
practice again. In between seizures, we have a
perfectly normal Beardie.
*~*~*~*~*~*~*~*~*~*~
A big
appreciative thank you to Linda Aronson, DVM for
this article. |
