First described as a specific, separate disease
in 1973, GSD myelopathy has been around a long time, but previously not
as well understood or distinguished from other pathologies. It gets its
common name from the fact that German Shepherd Dogs are found relatively
often, compared to much more uncommonly in a few other large breeds.
As a matter of fact, the peculiar syndrome seen in our breed is also seen
only (though rarely) in the Belgian Shepherd and the Old English Sheepdog,
and Dr. R. M. Clemmons, neurology professor at University of Florida's
veterinary school, feels what is seen in other breeds may well be a different
disorder. Those other degenerative myelopathies are probably not caused
by the same immune-system-related deficiency as we have in the GSD.
Diagnosis is by the process of elimination, since
regular neurological tests aren't definitive, except for the presence of
a brain fluid protein in the lumbar area of the cord. Your best bet would
be to consult an
experienced breeder who's been through it with
his own dog or dogs, and use the local vet for confirmation and medication.
He will see what you have: the dog atrophies in the haunches and croup.
Autopsy will not help you or your dog, but would find the obvious demyelination
(loss of the insulating sheath) of the spinal cord, destruction of some
large axons (nerve cells leading from the cord to smaller branch nerves),
and abnormal cells (or certain cells in abnormal locations). Similar
signs may be seen in the brain's white matter, and plasma cell infiltrates
in the kidneys and intestines give further evidence of the immune system
failure at the root of this disease.
Since GSD myelopathy is so similar to multiple
sclerosis, perhaps it would be worth trying the nutritional approaches
used by some who treat that human disorder. Wheat germ oil contains octocosanol,
a fatty or waxy high molecular-weight alcohol also given to patients with
encephalitis and cerebral palsy, and also contains linoleic acid (as do
several vegetable oils). But one fatty acid, docosahexanoic acid, is not
at all
abundant in normal diets, yet seems to be the
first one depleted from the nerves' myelin sheaths in such disorders as
MS. In many diets for MS patients, foods such as sardines and mackerel
are emphasized, because they are among the very few foods that can supply
this compound. Of course, vitamin B complex high in inositol, B6, B12,
and choline is also highly recommended as an adjunct to vitamin E for nerve-muscle
disorders.
Since only a percentage of patients with MS or
DM respond satisfactorily to a vitamin-only approach, the concomitant use
of drugs and exercise should always be prescribed. As of this writing,
there were three
FDA-approved drugs for MS that not only help
manage symptoms but also appear to "impact disease course" in relapsing
MS, according to the National Multiple Sclerosis Society. They are Copaxone
(Teva Marion), Avonex (Biogen), and Zanaflex (Athena Neurosciences). Your
vet would have to decide whether or not he wanted to "go off-label", since
these have not (yet?) been approved for dogs.
For several years, there was no generally accepted
treatment, but as breeders became aware of the benefits of high vitamin
E dosages, the veterinary profession began to see its efficacy and the
relation to the immune system. When I first encountered it, I got
an extra one or two years useful life out of one of my dogs by giving him
800 units (IU) a day, plus vitamin C for its synergistic effect.
Years later it was
discovered that 2000 IU of vitamin E daily, 500
mg of vitamin C twice a day, and a high-strength vitamin B complex twice
a day is the best dosage. Vitamin E is an important nutrient with a number
of physiologic
and pharmacological effects. As an antioxidant
it helps reduce oxidation of fats and increases the production of HDL cholesterol.
At higher doses it decreases production of prostaglandins and has anti-inflammatory
action There is no known side-effects to vitamin E at levels less than
4000-6000 IU per day (except in cats, where levels above 100 IU/day can
create hepatolipidosis. In DM, low serum and tissue concentrations of vitamin
E have been observed. I recommend that vitamin E be given to all
German Shepherd dogs. For GSDs less than 2 years
of age, give 400 IU of vitamin E daily. For older GSDs, give 800 IU of
vitamin E daily. If your dog develops DM, then the dose of vitamin E should
be increased to 2000 IU daily. Dr. Clemmons recommends the vitamin E be
dropped temporarily to
about 100 IU if the dog has to be given aspirin
for any reason during the treatment, and recommends that daily DEC (diethylcarbamazine)
replace the monthly heartworm medications ivermectin (Heartgard, Heartgard
Plus, Ivomec) and Interceptor because these increase immune responsiveness;
also use the DEC in place of styrid caracide or Filaribits. Personally,
I would simply stop all use of heartworm medication, because the dog with
DM isn't going to last as long as it takes for a case of heartworm to
become life threatening anyway. Flea control
should be limited to Precor™ for the house, and carbamates or pyrethrin/pyrethrum
on the dog.
Chemical-pharmacological treatment has largely
been via the use of aminocaproic acid, something my friend Wayne Riser
(founder of OFA) told me about many years ago. More recently, acetylcysteine
three times a day has found acceptance. It now appears the best treatment
is a combination of all three approaches, along with exercise. Alternate
day dosage with a steroid such as prednisone, plus acetylcysteine, added
to the aminocaproic acid and vitamin formula, is enough to keep the dog
owner
very busy and tied to the home, but it offers
the best chance at reducing progression, thus prolonging life considerably
more than in the past. The drugs should be given in liquid form, mixed
with a palatable solution such as chicken broth. There are generic varieties
available. Medication helps up to 80% of afflicted dogs, especially if
started early.
Hydergine, a prescription drug derived from ergot
fungus is being researched, since it seems to promote nerve regeneration.
For dogs with advanced DM, Dr. Clemmons suggests trying 5 mg three times
a day for at least three months.
I mentioned exercise, and this is the third of
the four-part fight against the disease. Every other day, the dog should
be given at least 30 minutes of aerobic activity such as vigorous walking
or swimming; if you
start late, build up to the strenuous level gradually;
if your dog can't do the most, do less, but make it regular and stretch
the limits where you can. The alternating days of relaxation are important
for repair and renewal. If the dog acts sore, give him the analgesic prescribed
by your vet (after he has "read up" on the interactions of medications
in regard to GSD myelopathy. The fourth part is stress reduction. The vitamin
C, that anti-stress vitamin, is there for a good reason, but take steps
to avoid stressful situations, including surgery; if the dog needs surgery,
make sure he gets the acetylcysteine as well.
Dogs with GSD myelopathy often develop lick granulomas,
which are ulcerations or (if you are lucky) callous-like reactions of the
skin to extremely frequent licking, sometimes chewing, at the location
of a
supposed itch. It is probably a case of the limb
feeling as if it has "fallen asleep", to put it into terms familiar
to human experience. The tingling sensation caused by incomplete
and erroneous signals by the
nerves serving that place is much like the irritation
caused by an ant bite, or hairs out of place, or anything in between.
In trying to lick it away, the dog actually softens and wears away the
hair and skin. The
best I could do for my dog was prick the vitamin
E capsule, squeeze out a little for topical application to the granuloma,
pop the rest into his mouth, and then give him some distraction such as
go for a walk. These ulcers on the feet or elsewhere don't easily respond,
but the battle must be waged if the dog's life and comfort are to be prolonged.
The approach to treatment of GSD Myelopathy that
is proposed by Dr. Clemmons is called "integrative treatment". It combines
conventional pharmaceutical treatment with "alternative medicine" or "supportive
therapy". Paraphrasing some of his comments might
be helpful here. Conventional drug therapy (medicines) has been of little
lasting help to patients with DM. However, the combination of exercise,
vitamins and certain drugs have delayed the progression of DM in many dogs.
Treatment has been directed at suppression of symptoms, and since the cause
of this autoimmune disease is not known, little has been done in the way
of finding out how to prevent it. There are possibly genetic, environmental
and toxic factors involved. Saying that Degenerative
Myelopathy is an autoimmune disease means the animal's immune system attacks
its own cells; in this case, the central nervous system. The myelin insulation
sheath around the nerves and axons (fibers) is gradually destroyed. It's
worst in the thoraco-lumbar area of the spinal cord, but can also affect
the brain stem and other nerve tissue.
Integrative or supportive treatment of German
Shepherd Dog Myelopathy as promoted at the University of Florida vet school
suggests the use of dietary alternatives and supplements to combat the
immune system, and are derived from an approach to treating Multiple Sclerosis.
You probably know at least one person with MS, and can recognize the similarity
in symptoms. Besides the vitamins E and C, the drugs, and the exercise
mentioned above, avoidance of toxins such as is found in pesticides and
lawn chemicals, and perhaps in some processed foods, is possibly helpful.
If you cannot manage "home cooking" with its
involved recipes, supplement dog food that is as natural as possible with
recommended aids. Soybean curd (tofu) protein contains flavonoids; raw
garlic (action is lost when is cooked or dried) is anti-bacterial and anti-fungal,
and may benefit the dog by reducing immune challenge. Ginger is also anti-inflammatory
and with garlic, can replace aspirin and other NSAIDs. Adding soy concentrate,
soy lecithin, and beta-carotene and other vitamins to commercial food is
recommended. Use "stress formula" B-complex containing 100 mg of most of
the B vitamin components; or use yeast as a good source of these B-complex
vitamins, trace minerals, and some protein. It is relatively inexpensive;
try half a tablespoon mixed in each meal. If your dog gets flatulence,
use a discount or mail-order vitamin B complex pill instead.
Antioxidants vitamins E and C are synergistic;
i.e., they work together better than they do separately. While dogs produce
vitamin C, those with DM may need more than they can manufacture. In excess,
it also can cause flatulence. I normally recommend not supplementing with
vitamin C for longer than a month or two at a time, but in the case of
a permanent, chronic disorder like DM, it's better to continue usage. Tolerance
in the intestines may be for as much as 3000 mg per day, but up to 1000
mg twice
a day should be enough unless it causes diarrhea.
Selenium also is synergistic, helping vitamin E to be more effective. It
can be toxic if given at more than 200 µg (micrograms) of selenium
per day. I take 200 µg whenever I feel I'm not getting much western
grain (good source of selenium) in my daily diet, and I weigh twice as
much as my largest German Shepherd Dog.
Clemmons says that "Omega-3 fatty acids such as
EPA (eicosapentanoic acid) and DHA (docosahexanoic acid) are the constituents
of fish oils that act as anti-inflammatory agents and may be worth trying
if your dog has an autoimmune disorder or arthritis." Fortunate is
the owner who can give an afflicted dog a couple of cooked sardines or
a small piece of salmon as a daily, natural source of such fatty acids.
A 1000-mg fish oil capsule, tablespoon of ground flax seeds, or flaxseed
or wheat germ oil supplement can do about the same thing. If you are really
"into" the health-food store shopping, 500 mg twice a day of GLA (gammalinolenic
acid), a fatty acid found in evening primrose and black currant oils is
an alternative anti-inflammatory without the
side effects of most anti-inflammatory drugs. All of the above should be
considered as optional adjuncts to conventional treatment with the drugs,
vitamins, and
exercise, not replacements for them.
Cauda equina syndrome, giant axonal neuropathy, and tumors may also mimic DM. Many cases of spinal and related nerve damage are due to sudden trauma, but some can result from encroachment of bone or tumors into the space occupied by the cord. Since nervous tissue does not regenerate, such conditions result in partial or complete paralysis. Symptoms similar to myelopathy may be brought on by a nerve cell degeneration normally associated with age. However, with the latter disorder the rapidly progressive nature of GSD myelopathy is not seen. Neoplasms also cause the dog to display symptoms similar to those of GSD myelopathy. These tumors on the spinal cord, neuroepitheliomas, have a special predilection for German Shepherd Dogs from six months to maturity at three years of age.
copyright Fred Lanting, may be forwarded only with permission of author:
Fred Lanting, Canine Consulting. Mr.GSD@hiwaay.net
Seminars: Canine HD & Other Orthopedic
Disorders