Dog Owner's Home Veterinary Handbook.pdf - Mr. Walnuts

INHERITED NEUROPATHIES
THE NERVOUS SYSTEM • 365
There are a number of rare diseases in which sensory and motor nerves degenerate.
With loss of sensation and motor function, an affected dog does not feel
the position of her limbs, is unable to position them correctly to prevent
stumbling, and fails to withdraw a leg from a painful stimulus.
The diagnosis is made by sensory and motor nerve conduction studies.
There is no cure, but because of the slow progression of the disease some dogs
live comfortably for many years. Most of these neuropathies are inherited as
autosomal recessive traits. Some of the most common ones are noted here.
Neuropathy of German Shorthaired and English Pointers is first noted at
3 to 4 months of age. The pup with this sensory neuropathy begins to lick and
bite at her paws, which become swollen, reddened, ulcerated, and eventually
mutilated. Loss of sensation can extend up the limb and involve the trunk.
The mode of inheritance is autosomal recessive.
Dachshund sensory neuropathy begins in longhaired Dachshunds at 2 to
3 months of age. It is characterized by uncoordinated gait, urinary incontinence,
and loss of sensation over the entire body. Self-mutilation of the penis
may be the first sign in males.
Global cell leukodystrophy is caused by an enzyme deficiency that results in
degeneration of nerve cells. It occurs in West Highland White Terriers, Cairn
Terriers, Beagles, Pomeranians, and Poodles. Signs are unsteady gait, head
tremors, nystagmus (a rhythmic movement of the eyeballs), and blindness.
Scotty cramp is an autosomal recessive disease in Scottish Terriers where
puppies show increased muscle tone when excited, stressed, or exercising vigorously.
They show a stiff, hyper gait. Diazepam (Valium) helps, and most of
these dogs can be comfortable pets.
Hypertrophic neuropathy in Tibetan Mastiffs begins at 7 to 12 weeks of
age and is characterized by hind-limb weakness that progresses to generalized
weakness and, ultimately, an inability to stand. Some dogs maintain a degree
of strength. This is an autosomal recessive disease.
Polyneuropathy in Alaskan Malamutes shows up at about 12 to 18
months of age. Initially, dogs show exercise intolerance but this can progress
to paralysis. Some dogs may stabilize, but most dogs continue on a downward
trend. Treatments have not been effective.
Hypomyelination diseases manifest when myelin, which forms a sheath
around nerve fibers, is not completely developed at birth. The result is that
nerve impulses are conducted very slowly. Hypomyelination occurs in Chow
Chows, Weimaraners, Samoyeds, and Bernese Mountain Dogs. One form,
called the shaking puppy syndrome, is a sex-linked recessive trait that affects
only males.
The characteristic sign of hypomyelination is muscle tremors involving the
limbs, trunk, head, and eyes of newborn puppies. The tremors get worse with