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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.
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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.
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