Dogs are among the most lovable and loyal pets in the world, which is why they’re so popular. They come with their fair share of accolades, but unfortunately are also susceptible to many serious health conditions.
One of these health concerns is Intervertebral Disc Disease, or IVDD, which is most commonly found in smaller dogs. Learn more about what causes IVDD, how to spot the signs of IVDD, and common treatments for IVDD by reading below.
What is Intervertebral Disc Disease?
Intervertebral disc disease (IVDD) occurs when the cushioning intervertebral discs between the vertebrae of the spinal column become displaced, deteriorate, bulge out, rupture, or burst (herniate) into the spinal cord space. When this happens, the discs press on the nerves that run through the spinal cord, which can cause pain, nerve damage, and in severe cases, paralysis.
IVDD is sometimes referred to as a slipped or herniated disc. IVDD is one of the most common neurological disorders in canines and reportedly affects 2 percent of the domestic dog population.
To understand IVDD, one must take a look at the intervertebral column. A canine’s spine is made up of individual vertebrae. These consist of seven vertebrae in the neck (cervical vertebrae), thirteen thoracic vertebrae in the back, seven vertebrae in the lower back (lumbar vertebrae), three fused sacral vertebrae, and vertebrae in the tail (caudal vertebrae).
Most canine vertebrae are made up of a body at the base, a pedicle (side) and arch (top), and a dorsal spinous process. The spinal cord travels through and is protected by the vertebral canal. Between most of these vertebrae lies an intervertebral disc. The discs are made up of the outer annulus fibrosus and the inner gelatinous nucleus pulposus.
You can think of a healthy intervertebral disc as a jelly donut, wherein the annulus fibrosus is the outer doughnut, and the nucleus pulposus is the gooey jelly in the middle. These intervertebral discs act as cushions between the vertebrae. When a disc become unhealthy, the jelly portion of the donut dries out, blood supply to the disc slows, and it does not repair itself once it starts to degenerate.
When this drying out process occurs, the outer donut weakens, and the dog becomes more prone to injury. Simple daily activities like jumping off a chair or even walking can cause this outer portion of the disc to tear. This will cause the jelly center to squeeze out, causing bigger problems.
IVDD mostly occurs in a dog’s neck or the last few ribs to the low back area. Neck lesions may affect a dog’s front legs or both front and rear, while back lesions will affect the back half of a dog’s body.
What dogs are most at risk for Intervertebral Disc Disease?
There are several breeds of dogs that are at increased risk for IVDD. These dogs are mainly classified as chondrodystrophic breeds, or dogs with abnormally short legs. Breeds include Dachshunds, Beagles, Bulldogs, Basset Hounds, Corgis, Cocker Spaniels, Pekingese, Shih-Tzus, and Miniature Poodles. IVDD occurs primarily when the dogs are middle-aged, or three- to six-years-old.
IVDD does also affect some non-chondrodystrophic breeds, such as German Shepherds, Labrador Retrievers, and Doberman Pinschers. For non-chondrodystrophic dogs, IVDD is most common in those aged eight to 10 years.
Whether chondrodystrophic or not, obese dogs are most at risk.
What Causes of Intervertebral Disc Disease in Dogs?
In order to understand the causes of IVDD in dogs, one must first familiarize the two types of IVDD found in pups.
- Type I typically affects chondrodystrophic breeds. In Type I IVDD, most common in the neck region of these smaller breeds, the outer layer of the discs will calcify, or harden. This damages the disc, and allows it to break down more easily. Forceful impacts like jumping and landing can cause one or more disc(s) to burst and the inner material to press on the spinal cord.
- Type II is a more gradual, chronic protrusion of disc material that typically affects nonchondrodystrophic breeds. In Type II, discs become hardened over a long period of time, eventually breaking down, bulging out, and compressing the spinal cord. When the nerves of the spinal cord become compressed, the nerve impulses are unable to transmit their signals to the final destination in the limbs, bladder, etc. Severe damage can cause loss of bladder and bowel control, or even paralysis. Type II IVDD typically has less severe signs and symptoms than Type I.
IVDD is a degenerative process and does not result from sudden trauma, but a sudden trauma can cause a rupture or herniation in a dog whose discs were already weakened by IVDD. Ruptured discs can occur from jumping or playing fetch. Injuries caused by attacks or being hit by a car can cause similar symptoms, but is not the same as IVDD.
Symptoms of Intervertebral Disc Disease
There is a wide range of signs and symptoms associated with canine IVDD, ranging from mild pain to complete paralysis. However, most cases will fall somewhere in between. Since the intervertebral discs essentially serve as the shock absorbers or the spine, there are plenty of signs you can look for from your dog. And since IVDD can lead to permanent nerve damage, recognizing your dog’s symptoms in a timely manner and getting treatment can be extremely important.
Some signs of IVDD include: