Degenerative Disc Disease
June, 1997
The Beagle is one of the top 4 or 5 dog breeds considered to
be susceptible to back problems. Although fractures and
dislocations of the spinal column can occur as a result of severe
trauma, the most common cause of spinal cord disease in dogs is
degenerative disc disease.
The spinal column is made up of a series of vertebrae, which are
separated by small cartilage discs. The fragile spinal cord runs
down a canal in the center of these vertebrae, carrying
electrical impulses back and forth between the brain and the rest
of the body. Degenerative disc disease occurs when an
intervetebral disc breaks down, allowing the soft center of the
disc, called the nucleus pulposus, to protrude or herniate and
put pressure on the spinal cord itself or the nerves that attach
to the cord.
Degenerative disc disease occurs in susceptible individuals of
both sexes, usually beyond 3 years of age. The degeneration of
the disc takes place over time, but the actual disc herniation
can be slow or sudden. It may occur after some major or minor
trauma to the spine, or during vigorous or minimal activity.
The signs of disc disease vary from pain alone, to complete
paralysis. The pain may be fairly mild or it may be severe enough
to make the dog reluctant to do stairs, to jump, or to move at
all. More severe disc herniations can cause incoordination,
wobbly gait and weakness. The worst cases exhibit complete
paralysis and loss of feeling to the extremities. About 80% of
degenerative discs occur in the lower back, with the remainder
occuring in the neck. Most disc herniations in the neck area
cause only pain, but when they do affect nerve impulses to the
legs, it involves all 4 legs. Disc problems in the back affect
the hind legs only. Your veterinarian will usually diagnose disc
disease on the basis of your history and the findings of the
physical exam. X-rays may be helpful, but frequently do not show
the site of the degenerative disc. A myelogram, X-rays taken
after injecting a dye into the fluid around the spinal cord, is
much more likely to show the exact location and severity of a
herniated disc. The myelogram is usually reserved for those cases
that have been chosen to be treated with surgery.
Most cases of disc disease will improve with conservative, or
medical, treatment. This involves enforced rest and drug therapy.
Enforced rest can be accomplished by confinement in a small room,
an airline kennel, a playpen or a crib. Disturbances should be
minimized, with exercise restricted to short leash walks away
from other animals, several times a day. The dog should have
soft, comfortable bedding and access to food and water. With dogs
that are totally paralyzed, frequent turning can prevent bed
sores. For those that have lost control of their bladder,
expressing it manually may be necessary to prevent a urinary
tract infection. Once pain has been controlled with medication,
physical therapy is helpful. Warm water baths help relax muscle
spasms. Muscle massage while bathing, or using a whirlpool,
promotes circulation. Controlled sitting-standing motions can be
helpful.
The main goal of medical management is to reduce inflammation and
swelling of the spinal cord. The main classes of drugs used for
this purpose are corticosteroids and non-steroidal
anti-nflammatories. Corticosteroids are cortisone derivatives
such as dexamethasone or prednisone. Non-steroidal
anti-inflammatories include aspirin, phenyl-butazone and a
relatively new drug - Rimadyl (carprofen). Other drugs may be
useful, such as muscle relaxants or medications to help promote
urination or defecation. Some cases respond in a day. Others take
several weeks.
Surgical intervention is usually reserved for the most severe
cases. Dogs with total paralysis and the loss of sensation to the
toes usually do not respond to medical treatment and require
surgery within 48 hours. Your local veterinarian likely does not
do this type of surgery, but will refer you to a hospital where
it can be accomplished. It is a very costly procedure. Surgery
involves the removal of any disc material in the spinal cord, as
well as removal of normal discs from adjacent intervertebral
spaces to help prevent future problems. The overall recurrence
rate is about 50%. Surgical aftercare at home is rest and
medications, similar to the nursing care already described. Most
dog owners will never encounter a serious bout with disc disease,
but if your hunting dog shows a strong susceptibility to this
problem, an early retirement may save him a lot of discomfort.