Introduction
Type I and Type II intervertebral disk disease affects the disks located between the spine, but there are significant differences between these two forms of intervertebral disk disease. Type I intervertebral disk disease more commonly affects certain dog breeds, whereas Type II intervertebral disk disease affects older dogs. Regardless of the type of disk disease that has occurred, prompt medical treatment is needed to prevent further damage from occurring to the disks.
Types of Intervertebral Disk Disease
Type I
Type I intervertebral disk disease is a degenerative disorder that is characterized by disk degeneration on the outer layer of the disk and mineralization, or hardening, of the inner layer of the disk. The outer layer eventually ruptures, and the hard inner layer presses up against the spinal cord. Multiple disks can be affected, and the degeneration can begin at an early age with symptoms appearing by 3 years of age.
In most cases, Type I intervertebral disk disease affects chondrodystrophoid breeds. These types of breeds have short stubby legs and include: the American Cocker Spaniel, the Basset Hound, the Beagle, the Corgi, the Dachshund, the French Bulldog, and the Pekingese. Type I intervertebral disk disease is often very painful, and cases can range from mild to extreme degeneration.
Type II
Type II intervertebral disk disease is a slow and gradual degeneration of the inner portion of the disk. In this case, the inside of the disk becomes soft and spongy and leads to a bulging disk condition that compresses the spinal cord. Most cases of Type II intervertebral disk disease affect dogs between 8-10 years of age. This type of disk disease is not normally as suddenly painful as Type I intervertebral disk disease, and in many cases less disks in the back and neck are affected.