Just like people, dogs have disks, or round cushions of cartilage sandwiched between the vertebrae, or individual bones in the spine. Their tough outer layer and a soft inner layer, called the nucleus, act as shock absorbers.
Sometimes the outer layer ruptures and the nucleus actually pushes up into
the spinal cord. This is called Hansen’s Type I disk disease, and it generally affects dogs who are between 3 and 6 years old. Hansen’s Type II disk disease occurs when both the outer layer and nucleus degenerate and bulge upward into the spinal cord. This condition usually appears in dogs 8 years or older.
Both diseases cause pain and nerve dysfunction. If you’ve ever thrown out
your back, you have a good idea of how painful disk disease is.
Risk factors and detection
Dogs with long backs are at a higher risk for disk rupture. Breeds predisposed for Hansen’s Type I rupture include the dachshund, basset hound, bichon frise, toy poodle, Pekingese, beagle, Welsh corgi, Lhasa apso, Shih Tzu, and cocker spaniel. Hansen’s Type II disease occurs mostly in Doberman pinschers, Labrador retrievers, and German shepherds.
Hansen’s Type I disk disease often causes an acute, or sudden, disk rupture. Type II tends to progress slowly. About three-fourths of all disk ruptures occur in the midback area, and the rest mostly appear in the neck.
The signs of disk disease vary with severity and location in the spine. A
mild rupture can cause slight pain, but severe ruptures can cause irreversible paralysis. Most cases fall somewhere in between.
Signs of disk disease include:
- trembling, whining, or crying out with certain neck or back movements
- reluctance to move or turn the head
- appetite loss
- an arched back or a noticeable twist to the back
- reluctance to jump up or climb stairs
- an unstable walk
- toes knuckling under or feet dragging
- inability to use the legs.
If you notice any of these signs, take your dog to the veterinarian immediately. The levels of spinal cord damage can progress quickly from pain to an unstable gait to loss of bowel and bladder control and paralysis.
Prompt treatment often prevents further damage.
Your veterinarian first will observe your dog’s gait, then perform a thorough
physical examination. During the exam, your veterinarian will turn your dog’s toes under to see if he straightens them out. Next, the doctor will
manually palpate each vertebra along the neck and back, move the neck in several directions, and test your dog’s spinal reflexes.
Sometimes these manipulations are painful, so don’t be alarmed if your
veterinarian places a muzzle over your dog’s mouth. The doctor will usually save more painful movements until the end of the examination.
Your veterinarian likely will X-ray your dog to look for signs of a ruptured disk and to rule out such conditions as arthritis, a fractured vertebra, or tumor in the spine. The doctor will anesthetize your dog, both for his comfort and to let the technician obtain good X-rays. With disk disease, the X-rays often show calcified disks or a narrowing between vertebrae.
Prevention and treatment
You can’t prevent disk disease, but a lean, fit dog is at lower risk. Minimizing rough play and jumping in at-risk breeds can help, too. But sometimes your best efforts won’t prevent disk rupture, especially with dachshunds.
Your veterinarian will treat your dog based on his symptoms. Neck disk
problems can be painful but rarely lead to paralysis. If your dog has neck pain but no neurologic abnormalities, the veterinarian may recommend pain relievers or anti-inflammatories, activity restrictions, and using a harness instead of a leash for walks.
Dogs with a hunched, painful back often respond to rest and oral medication.
But those with neurologic damage need hospitalization so your veterinarian can restrict activity, administer medication, and monitor your dog’s condition.
For recurring problems or paralysis, your veterinarian likely will recommend
surgery to relieve the pressure on the cord. The procedure is involved,
sometimes unsuccessful, and mandates a long recovery period. Your veterinarian can best explain your dog’s treatment and prognosis, and he or she may refer you to a specialist.
