Hypothyroidism in dogs can cause sudden onset of epilepsy, unprovoked aggression, moodiness, depression, hyperactivity, anxiety, and other undesirable behaviors.
Behavioral changes are one of the most undesirable consequences of thyroid dysfunction in dogs. And unfortunately, in North America, the primary reason for pet euthanasia stems from undesirable behavior rather than disease. Often, these changes are related to thyroid dysfunction. Researchers at Tufts University report that 77 percent of the dogs with seizure disorders that they studied had thyroid dysfunction. In addition, the major behavioral changes reported in dogs withy thyroid dysfunction included aggression, seizures, fearfulness and hyperactivity with some dogs exhibiting more than one of these behaviors.
Who Is Affected?
Male and Female canines are affected equally. In addition, spayed and non-spayed animals are equally affected. Onset of thyroid disorders tends to peak around the time of puberty. Neutering does not fix the problem and often makes it worse. Thyroid dysfunction is also more common in purebreds than in mixed breeds. Certain breeds, such as boxers, German Shepherds, Collies, Golden Retrievers, English Setters, Labrador Retrievers and Akitas, are also more prone to canine hypothyroidism.
Symptoms and Signs
Both hypothyroid humans and canines have reduced cortisol clearance, which causes elevated levels of circulating cortisol. Elevated cortisol causes a constant state of stress that can result in impaired mental function and irrational reactions characterized more by stress than by reason.
Symptoms of hypothyroidism include major depression, unprovoked aggression, joint pain, sudden onset of seizures, anxiety, phobias, submissiveness, passivity, disorientation, moodiness, erratic temperament, hypo-attentiveness, compulsiveness, and irritability. After the episodes of aberrant behavior, a majority of these canines were reported to behave as if they were coming out of a trance-like state and seemed unaware of their previous behavior. Researchers report that a similar pattern of symptoms of hypothyroidism in horses.
Diagnosis
Because the TSH test is often falsely increased and decreased in canines, it is not recommended as the sole thyroid function test. It is important for dogs suspected of having hypothyroidism to have tests for FT4 and FT3 as well as TSH. Tests for thryoid antibodies should also be performed.
Treatment
Treatment for hypothyroidism with twice daily doses of levothyroxine rapidly reversed symptoms with behavioral improvement generally noted within one week. However, a dramatic reversal of behavior with resumption of previous problems has been reported to occur in some cases if only a single dose is missed.
Seizures in Canines
Seizures in canines, regardless of the cause, can be aggravated by nutritional deficiencies, particularly deficiencies of amino acids. Dietary sources of high quality animal protein in the least processed forms provide an optimal canine diet.
Polyglandular Syndromes
Canines susceptible to autoimmune hypothyroidism may also become more susceptible to other autoimmune disorders. Research shows that canines as well as humans can develop autoimmune polyglandular syndromes. Schmidt’s syndrome is the most common of the polyglandular disorders to occur in canines, and this disorder is most likely to occur in the Standard Poodle, Old English Sheepdog, Bearded Collie, Portugese Water Dog, Novia Scotia Duck Trolling Retriever and Boxers although any breed can become affected.
The copyright of the article Canine Epilepsy in Autoimmune Disease is owned by Elaine Moore. Permission to republish Canine Epilepsy in print or online must be granted by the author in writing.
My purebred pomeranian was recently diagnosed with epilepsy, she is only 4
years old. She began having epileptic attacks which we thought were stress
induced, when I would take her to the groomer. Now she's had two while
sleeping.
She's not on meds at the moment but we're going to
add some supplements to her diet. She eats specially prepared human food,
all organic, very high quality, etc.. The vet approves of her diet.
She had the TSH/T3/T4 tests and landed within the ranges given,
although on the low end. The awareness is growing for human subclinical
hypothyroidism, which is hypo with "normal" test results, why not
dogs? The best hypothyroid docs treat their human patients based on
symptoms and not solely lab results, why not dogs too? I think it would be
helpful to give her a very low dose supplement but the vet wants to wait.
We're keeping an eye on it and she'll probably go on meds at some point the
vet said.
Symptomwise, I have noticed she often seems a little
depressed. She also seems to sleep a lot more than before. She's having
some anxiety, submissiveness, passivity, and moodiness too. It's so vague
and sometimes we attribute it to other things so we're not sure.
Also, interesting thing I was told by another vet, that dogs who undergo
trauma, particularly ceserean section (common with small dogs) very often
will develop epilepsy at around 3 - 5 years of age.
I will say
that epileptic seizures in a dog are scary to watch and as a pet
"mom", I feel so helpless, because all I can do is comfort her
and speak softly to her. I know she's aware at the time of the seizure
because I can see the terrified expression on her face and in her eyes. For
several, she seemed to know they were coming and stayed close to me.
Fortunatly, the seizures are not frequent.
Jan 27, 2009 8:03 PM
Guest
:
My purebred pomeranian was recently diagnosed with epilepsy, she is only 4
years old. She began having epileptic attacks which we thought were stress
induced, when I would take her to the groomer. Now she's had two while
sleeping.
She's not on meds at the moment but we're going to
add some supplements to her diet. She eats specially prepared human food,
all organic, very high quality, etc.. The vet approves of her diet.
She had the TSH/T3/T4 tests and landed within the ranges given,
although on the low end. The awareness is growing for human subclinical
hypothyroidism, which is hypo with "normal" test results, why not
dogs? The best hypothyroid docs treat their human patients based on
symptoms and not solely lab results, why not dogs too? I think it would be
helpful to give her a very low dose supplement but the vet wants to wait.
We're keeping an eye on it and she'll probably go on meds at some point the
vet said.
Symptomwise, I have noticed she often seems a little
depressed. She also seems to sleep a lot more than before. She's having
some anxiety, submissiveness, passivity, and moodiness too. It's so vague
and sometimes we attribute it to other things so we're not sure.
Also, interesting thing I was told by another vet, that dogs who undergo
trauma, particularly ceserean section (common with small dogs) very often
will develop epilepsy at around 3 - 5 years of age.
I will say
that epileptic seizures in a dog are scary to watch and as a pet
"mom", I feel so helpless, because all I can do is comfort her
and speak softly to her. I know she's aware at the time of the seizure
because I can see the terrified expression on her face and in her eyes. For
several, she seemed to know they were coming and stayed close to me.
Fortunatly, the seizures are not frequent.
Jan 28, 2009 11:06 AM
Elaine Moore
:
Hi, Even though your little Pomeranian's seizures aren't frequent, it
seems it would be good to use anti-convulsant medications to prevent a
grand mal seizure from occurring. I've known many people whose dogs were on
primidone for years after having just one seizure. Primidone is an
anti-convulsant that breaks down or metabolizes into phenobarbital. Ask
your vet about this.
I'd also look into the role of healthy diet
that I used for the second resource here. Diet can make a big difference.
Sometimes it's impossible to determine the cause of seizures but friends of
mine pinpointed their dogs' seizures to thyroid disorders, pesticides, and
food sensitivities.
There's also a problem with reference ranges
for thyroid function tests. They were established based on tests run on a
limited number of canines. While most normal dogs will have levels that fit
into the range, the reference range may not fit all dogs. If levels are on
the low side, your vet might consider a low dose of replacement hormone.
Our older boxer mix had levels on the low side and our vet gave us a choice
if we wanted to use replacement hormone. Since his mother was severely
hypothyroid, I opted for it and I'm glad I did. This was 6 years ago and it
tempered some aggressive signs he was showing up and improved his patchy
coat, puffiness, etc. He's 11 years old now. Best, Elaine
