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

THE NERVOUS SYSTEM • 377
In this drawing, (A) is a normal disc; (B) is an acute Hansen Type 1 disc rupture;
(C) is a Hansen Type 2 disc rupture.
that the entire disc, surrounded by an unbroken capsule, can bulge outward.
This is called a Hansen Type 2.
The diagnosis of ruptured disc is made by neurological examination and imaging
studies including spine X-rays, a myelogram, and possibly a CT scan or MRI.
Ruptured discs in the back of the Hansen Type 1 occur in small breeds
such as the Dachshund, Beagle, Cocker Spaniel, Pekingese, and small mixed
breeds. In fact, ruptured discs are more frequent in Dachshunds than in all
other breeds combined.
The capsule begins to degenerate at about 2 to 9 months of age, and signs
of impingement on the spinal cord appear at 3 to 6 years of age. About 80 percent
of Type 1 ruptured discs occur in the lower back between the last thoracic
and the first two lumbar vertebrae. Most of the remainder occur in the
neck. There is often a history of mild trauma, such as jumping off a sofa, but
normal movements are sufficient to cause a Type 1 rupture. Occasionally,
more than one disc becomes ruptured.
The symptoms of a Type 1 rupture usually come on gradually but can
appear with sudden explosiveness. The main sign is pain. The dog holds her
back stiffly and may cry or whine when patted or handled in the injured area.
She usually refuses to walk up stairs or jump into a car. Neurological signs
include weakness, lameness, and a wobbly gait. A dog experiencing the severe
back pain of an acute rupture will have a hunched-up position and a tight
abdomen. The dog may pant and tremble. Sudden disc ruptures can produce
complete hindquarter paralysis.
Hansen Type 2 discs ruptures occur in the larger breeds, including German
Shepherd Dogs and Labrador Retrievers. The entire disc, surrounded by its
capsule, gradually impinges on the spinal canal. Symptoms appear in dogs 5 to
12 years of age. Because the process is gradual, symptoms progress slowly.