Intervertebral Disc Disease in Dachshunds
By Claire Kovalcik
Dachshunds are genetically predisposed to a condition called Intervertebral Disc Disease (IVDD). IVDD can refer to all pathological disorders involving the intervertebral discs and can affect any of the discs in the spinal column, however, there are 2 general types of IVDD.
Dachshunds are specifically predisposed to Hansen Type I IVDD, also known as chondroid metamorphosis. This kind of IVDD occurs in breeds that are prone to cartilage maldevelopment, known as chondrodystrophism. Chondrodystrophic breeds include long and low dogs such as Dachshunds, Corgis, and Bassett hounds, but also include Beagles, French Bulldogs, and Cocker Spaniels (1,2,4,5). The changes that occur to the disc usually happen between 2 months and 2 years of age. Although the disc changes occur during this time, clinical signs usually appear later, between 3- 6 years of age (2). Less commonly, dachshunds may be affected by Hansen Type II IVDD, also known as fibroid metamorphosis. This occurs generally later in life, and can affect any breed of dog. Dachshunds are by far the most highly represented breed to display IVDD; 2% of the general dog population is affected, however 45% of dachshunds between the ages of 4 and 7 years of age are affected with clinical disc disease (5). Dachshunds make up 45- 70% of all canine clinical cases of IVDD. (5)
The intervertebral disc can be compared to and described as a jelly donut. The intervertebral disc is composed of 2 discrete portions: the nucleus pulposus on the inside, which will now be referred to as the jelly, and the annulus fibrosis surrounding it, which will now be referred to as the donut.
In Hansen Type I IVDD, or chondroid metamorphosis, the jelly begins to dehydrate, and hyaline cartilage invades it. This can lead to mineralization, which causes the formerly jelly like nucleous pulposus to become gritty and dry. At the same time, the outer donut degenerates, and eventually ruptures, as seen in Figure 1 below. Now the gritty jelly busts out into the spinal canal, presses on the spinal cord, and causes varying amount of pain and neurologic signs based on location and amount of extrusion (2,5). It is common for these chondroid changes to occur in multiple intervertebral discs. In 85% of cases, the affected discs occur in the lower part of the back, generally around the level of the last rib and a few disc spaces down. Signs can include unwillingness to jump, pain or weakness in rear limbs, crying out loud in pain, hunched posture, muscle spasms, incontinence (loss of bladder or bowel control), and even paralysis (1,2,3,4,5). The other 15% of cases occur in the neck region and signs include neck pain, stiff gait, spasms of the neck and shoulder muscles, pain in the front legs, but rarely paralysis (5). Hansen Type I IVDD usually appears acutely.
In Hansen Type II IVDD, or fibroid metamorphosis, the jelly begins to dehydrate, and fibrocartilage invades it. The disc slowly becomes more hardened and slowly bulges disk material into the spinal canal, as seen in Figure 1 below. This generally occurs in only one disc, and in older dogs 8-10 years of age (2). Because they are due to slowly progressive bulging rather than busting, they are not generally acutely debilitating like Hansen Type 1 extrusions. Clinical signs usually include progressive signs of weakness in the back limbs, referred to as paraparesis, as well as some degree of back pain. (2)
Although treatment and management of IVDD is possible, prevention is preferable. Weight management is essential in protecting your pet. Obesity and lack of postural muscles are thought to increase the risk of disc calcification (3). Dachshunds should be trained to use ramps or stairs to get up onto couches or beds, and should never be allowed to jump from high places (1,2,3,4). Their short legs and long backs take the impact of landing harder than many other breeds, and predispose them to musculoskeletal and spinal problems. It is suggested, but not proven that exercise, even including stair climbing, reduces the incidence of disc calcification in chondrodystrophic dogs (3). Other sources suggest stair climbing should be avoided. Either way, it is widely accepted that a healthy weight, active dachshund will be less predisposed to IVDD than his overweight, less active counterpart. A harness rather than a collar should be used in dachshunds who pull on the leash to prevent unnecessary straining on their necks. There is now known to be a hereditary inherited component to IVDD in dachshunds (3). For this reason, it is not recommended to allow animals that have been affected with IVDD to reproduce. Spaying and neutering is recommended for these animals.
If the clinical signs mentioned earlier such as weakness or paralysis of the hind limbs are noted, your animal should be taken to your veterinarian immediately. One of the best prognostic indicators is speed of treatment (2). Your veterinarian will likely initially perform radiographs (commonly referred to as x-rays), but may want to pursue other imaging options such as a myelogram, an MRI, or a CT scan. These are all ways to help the extruded disc material and spinal cord damage become more visually apparent.
Treatment of IVDD can be medical or surgical in nature. When disc extrusion does not seem to have caused spinal cord damage, medical therapy may be more likely to be pursued. If signs such as paralysis occur, it is imperative that your pet be taken to surgery to remove the disc material that is compressing the spinal cord. It is recommended to perform surgery within 24 hours of the dog “going down” in order to increase the likelihood of regaining function of the affected nerves (2). There are multiple approaches to performing surgery on an IVDD dog, but they are not within the scope of this article. The intent of all of these different approaches to surgery is to remove the disc material that has extruded into the spinal canal and is compressing the spinal cord.
Prognosis of the IVDD patient depends on the type of IVDD as well as the time they have been affected. Animals that still have feeling in their legs and are able to go to surgery quickly have a better prognosis than those that are no longer feeling pain and wait a longer time before going to surgery (5). With both medical and surgical treatments, cage rest and physical therapy will be essential. Some dogs will not fully recover even when treated appropriately. Unfortunately, there are cases where softening of the spinal cord may occur, which is referred to as myelomalacia. There is a generally poor prognosis associated with this condition and euthanasia may be the most humane choice. In other cases where there is long term damage to the spinal cord but no softening, it is worth mentioning that dachshunds can still have a wonderful quality of life without full use of their hind limbs. Wheelchairs have been developed that can give them the mobility they need to get around, and incontinence problems can be manageable. Hind limb paralysis or weakness does not equal a death sentence.
IVDD is a serious and common condition that can occur in dachshunds. Knowing prevention techniques and clinical signs to look out for will help aid in the prevention and diagnosis of this disease.
Figure 1. Hansen Type I Vs. Hansen Type II IVDD protrusions (2)
1. Intervertebral Disc Disease in Dogs. Texas A&M University Veterinary Medicine & Biomedical Sciences. 2015. http://vetmed.tamu.edu/news/pet-talk/intervertebral-disc-disease-in-dogs.
2. Newton C, Nunamaker D, Shores A. Intervertebral Disk Disease. Textbook of Small Animal Orthopaedics. Chapter 62. 1985.
3. Rusbridge C. Canine chondrodystrophic intervertebral disc disease (Hansen type I disc disease). BMC Musculoskeletal Disorders. Volume 16(1). 2015.
4. Disc Disease. UC Davis Veterinary Medicine. http://www.vetmed.ucdavis.edu/vmth/small_animal/neurology/newsletters/disc_disease.cfm
5. Ackerman L. Nervous System Disorders: Intervertebral Disc Disease (IVD). The Genetic Connection: A Guide to Health Problems in Purebred Dogs. 136-7. 1999.