Slipped Invertebral Disc
Dachshunds are prone to slipped discs as a result of its short legs and long back. Mild injury causes pain, while severe damage can result in paralysis. The bowels and bladder may be affected, losing their nerve supply and ceasing to work properly.
The spine is composed of a series of vertebrae. The spinal cord is protected within a bony spinal canal formed by overlapping vertebrae. Intervertebral discs are located between each vertebra from the head to the tail. They allow for flexibility of the spine. A normal intervertebral disc has two distinct components - a fibrous outer casing, and an inner gelatinous center. The nucleus pulposus is normally 80% water, and has shock absorbing properties.
The nucleus pulposus of the disc slowly degenerates during the first few years of life. It loses a high percentage of its water and may become partially calcified. As this occurs, the outer casing of the disc becomes more susceptible to cracks and fissures. Normal activity or minor trauma to the discs such as jumping, falling while playing, or running can initiate disc extrusion.
Approximately 85% of the disc problems occur in the thoracolumbar area (back) and 15% occur in the cervical area (neck). When the disc extrudes, the nuclear content extrudes upward into the spinal canal. This results in pressure and compression on the spinal cord and/or spinal nerve roots. The compression collapses blood vessels and decreases circulation leading to deprivation of oxygen and glucose to the nervous.
The hallmark of cervical disc disease is neck pain. The muscles in the neck are tense or quivering, the nose is often pointed toward the ground, muscle tremors may be palpated in the neck and shoulder areas, the back may be arched, and there is reluctance to move the head from side to side or to lift the chin and look up.
Pain is elicited when the head is moved or the muscles in the neck are palpated. Posturing with the nose held close to the ground may result in arching of the back. Weakness or paralysis of all four limbs or lateralization to one side may be present, but often is not.
A nerve root running to one front leg may become "pinched" leading to lameness or reluctance to place weight on the leg. The pain can be persistent and unrelenting or it may be intermittent. Due to the pain, a dog is usually less active - reluctant to jump, play, or go on walks. Many dogs are content to lay and sleep most of the day and may hide. Sometimes a dog will have a diminished appetite or may back away from the food bowl while attempting to eat. Dogs with cervical disc extrusions will often be quite vocal in demonstrating pain, especially when picked up. At times, seemingly unprovoked, they may cry out unexpectedly.