Disc Disease in Dogs

Just like people, dogs can experience the pain of a "slipped disc" in their back. More properly referred to as intervertebral disc disease (IVDD), this degenerative disease of the spine involves a herniation of one of the gelatinous, cushioning discs that's between each vertebra. IVDD tends to develop slowly, although there are scenarios wherein the disc ruptures abruptly. Either way, the dog generally shows signs of pain, including reluctance to move, weakness, shivering or trembling, lethargy, and crying or whining.

While any dog can suffer from IVDD, especially as it ages, the disease most often occurs in breeds with long backs or short legs, such as dachshunds, corgis, beagles, chihuahuas, and basset hounds, but it can also strike large-breed dogs, including German shepherds, Labrador retrievers, and doberman pinschers. Typically, the affected dog is between the ages of three and seven when symptoms first strike.

If the IVDD is fairly mild and treated early, most dogs do well with conservative treatment. However, in severe cases, surgery might be the only solution. Here's what you should know about disc disease in dogs, including its cause, symptoms, and treatment.

What Is Disc Disease?

A common malady seen in long-backed dogs, although other breeds can be affected as well, intervertebral disc disease (sometimes called IVD, IVDD, or just disc disease) is a degenerative disease that affects the spinal column, causing compression of the spinal cord or pinching of the nerves branching off this delicate structure.

Your dog's spinal column consists of many separate vertebra (bones) with gel-like discs in between each one, hence intervertebral disc. These discs serve to cushion the individual vertebra, acting as shock absorbers. The typical dog has seven cervical (neck) vertebrae, 13 thoracic (chest) vertebrae, seven lumbar (lower back) vertebrae, three fused sacral vertebrae in the hips/pelvic area, and a variable number of caudal (tail) vertebrae, depending on the length of the individual dog's tail.

Each spinal disc is something like a jelly donut, with a tougher outer section called the annulus fibrosus and a soft center called the nucleus pulposus. As dogs age, wear-and-tear tends to take a toll on the spine, leading to degeneration of the bone and the intervertebral discs.

There are two main types of IVDD that affect dogs: Hansen type 1 and Hansen type 2.

Hansen type 1 IVDD tends to strike dogs with short legs and long backs. Up to 25 percent of dachshunds will have at least one episode of this painful condition during their lifetime. In this form of IVDD, the nucleus pulposus becomes dry and hard. While this process happens fairly slowly over time, the eventual result is often quite abrupt. The dog jumps or makes an abrupt movement, causing the disc to rupture and release the hardened center, which then presses against the spinal cord, causing an acute episode of pain, weakness, and even occasionally paralysis or inability to urinate.

Hansen type 2 IVDD most often strikes middle-aged large-breed dogs. German shepherds are especially predisposed to this back disorder, although any dog is potentially at risk. In this form of disc disease, the annulus fibrosus slowly becomes softer than normal and begins to bulge outwards, putting more and more pressure on the spinal cord. Unlike Hansen type 1, there isn't generally any abrupt or acute episode of pain, but rather, a slow progression of stiffness, difficulty walking, and sometimes pain, which is usually milder than the pain experienced by dogs with Hansen type 2 IVDD.

In the vast majority of dogs, IVDD will strike either the thoracic or lumbar spine, with the discs between the 11th and 12th thoracic vertebrae or the discs between the second and third lumbar vertebrae being the most commonly affected. However, in 15 percent of dogs, almost all of them poodles, dachshunds, or beagles, the herniation occurs in one of the cervical (neck) vertebral discs.

Symptoms of Disc Disease in Dogs

The symptoms of disc disease in dogs can range from quite mild to very severe, depending on the part of the back that's affected and the severity of the spinal cord compression. While you might choose to adopt a "wait and see" attitude with a dog that's only showing very mild symptoms, your dog needs immediate veterinary attention if it is in severe pain, unable to walk at all, having difficulty controlling its bowels or urination, or appears paralyzed.

Some common symptoms of disc disease include:

If your dog's IVDD is very mild, the only symptoms may be reluctance to walk or jump, or subtle signs of pain. However, in dogs with more advanced disease, it's common to observe signs of severe pain, including shivering or trembling, refusal or inability to walk normally or get up from a lying position, keeping the back hunched or the head hung low, or crying when trying to move. Some dogs will walk with a staggering gait, or cross their legs as they walk. Others will walk with their paws knuckled under, or splayed out for balance.

In dogs with the most advanced levels of IVDD, you might see a complete inability to walk or even stand, paralysis of the back legs, loss of bladder control, or a lack of response to stimulation that would normally be painful. These symptoms indicate a medical emergency that requires immediate veterinary attention. However, it's always best to bring your dog to the vet any time you notice new signs of illness, pain, or other disorders.

Causes of Disc Disease

For the most part, disc disease is a condition of wear and tear to the intervertebral discs that builds over time, creating dryness, brittleness, or weakness. Eventually, the dry, weak disc bulges or ruptures, putting pressure on the spinal cord or the nerves exiting the spinal cord. While IVDD is a very common condition, and does tend to develop in middle-aged or older dogs, it should not be shrugged off as just a "normal part of getting old," as it is not inevitable in all senior canines.

For most dogs with Hansen type 1 IVDD, it's a sudden movement or sharp jarring force to the back, such as jumping off a couch, that causes the disc to burst, but the slow process of degeneration was happening prior to that incident.

Certain breeds of dog are more prone to IVDD, due to their anatomy or genetics. Some of the breeds most commonly affected by this disorder include:

• German shepherds
• Welsh corgis
• Dachshunds
• Chihuahuas
• Poodles
• Cocker spaniels
• Labrador retrievers
• Beagles
• Lhasa apsos
• Pekingese

Diagnosing Disc Disease in Dogs

Your veterinarian may well make a tentative diagnosis of IVDD if your dog is one of the high-risk breeds and shows characteristic symptoms of pain, difficulty walking, weakness, or paralysis. However, it is important to definitively diagnosis disc disease if it is likely your dog will require surgery. Therefore, your vet will carry out a physical exam and order x-rays. In some cases, especially if surgery is a possibility, an MRI will be ordered as well.

During the physical exam, your vet will gently move your dog's head up, down, left, and right to check for signs of discomfort. Pain during these maneuvers could be indicative of a compressed disc in the neck. Even if your dog is stoic at the vet and never cries out, any resistance your dog shows could mean it is having pain.

Your vet will also press on each individual vertebra down your dog's back. If your dog has a compressed disc in its back, it will react when your vet presses on the area. Stoic dogs may not cry out, but their back will spasm when the vet presses on an area with a compressed disc.

Another part of the exam is checking your dog's gait. The vet will look for stiffness, limping, hunched or odd body postures, splaying of the legs, or knuckling under of the paws.

Next, your vet will test something call proprioception in your dog. That's just a big word for knowing where your limbs are without having to actually look at them. This sense can be disrupted in dogs with IVDD. To test this, your vet will flip your dog's paws over to see how quickly your dog flips them back.

Finally, your vet will test your dog's deep pain response by pinching one of its toes to see if there is a reaction. These tests are tools for your vet to determine how severe (or mild) your dog's disc disease flare up is.

Your veterinarian may use a common grading scale to evaluate your dog's level of symptoms. This helps determine the severity of the problem, as well as the best course of treatment.

Grade 1: Symptoms include head low to the ground, muscle spasms, back arching, trembling or crying out in pain, and not wanting to move or jump.

Grade 2: Symptoms include weakness in all four legs (if compression is in the neck) or the back legs (if compression is in the back). When walking, the dog may cross its legs accidentally, walk with its legs splayed out, or it may knuckle on its paws.

Grade 3: Symptoms include the ability to wag the tail and move the legs, but not enough strength to walk.

Grade 4: Symptoms include an inability to move all four legs. The dog is unable to stand or walk but will still have 'deep pain' response; that is, it will react when its toes are pinched.

Grade 5: Symptoms include not only an inability to walk, but also the loss of a deep pain response. This is rare but very serious when it does occur.

X-rays can help identify bone fractures, tumors, calcified discs, and compression in the vertebrae. If it appears that spinal compression is severe, the dog will probably be referred for an MRI, which gives a much clearer picture of the problem and allows the veterinarian to determine whether or not surgery is required. Your dog may need to be sedated for x-rays and will be under general anesthesia if an MRI is required.

Treatment

There are two basic modalities for treating disc disease in dogs: conservative treatment with medication and rest, and surgery. Which of these is right for your dog will depend on the severity of the disc disease, the level of your dog's pain and other symptoms, and your dog's overall health and age.

As a rough rule of thumb, dogs with symptoms that fall into grades 1 through 3 can be managed conservatively. This includes pain medications to help control the dog's discomfort along with anti-inflammatories. Many dogs with grade 1 disc disease will recover within a few days once their pain is minimized. However, most dogs with grade 2 or 3 symptoms will also need strict rest for at least two or three weeks. This generally means being restricted to a crate other than brief outings for toilet needs. Note that if your dog's condition continues to deteriorate, or its level of pain and disability continue, surgery may ultimately be required.

Dogs with symptoms that fall into grade 4 usually need surgery, and dogs with grade 5 symptoms require emergency surgery to prevent the risk of permanent paralysis. Ideally, a dog with paralysis needs surgery within the first 24 hours for the best chances of full recovery.

There are a few different procedures and techniques used in disc surgery, but all involve removing a small piece of bone over the damaged disc, as well as removing bulging disc material, so as to relieve pressure on the spinal cord. Spinal surgery is very expensive and requires a long recovery period, as well as physical therapy.

Prognosis for Dogs with Disc Disease

The prognosis for your dog with disc disease depends greatly on the severity of the degeneration. For most dogs with symptoms mild enough to fall into grades 1 through 3, a full recovery can be expected with pain control and rest. If your dog requires surgery, its prognosis is still fairly good. Up to 90 percent of dogs with grade 4 or lower symptoms recover fully after surgery. However, dogs with grade 5 symptoms have only a 50-percent chance of making a full recovery with surgery that happens within the first 24 hours after paralysis begins, and even lower odds if surgery is delayed beyond that point.

Note that even dogs who have successful surgery are at risk of experiencing back problems in other discs, especially if they are a higher-risk breed.

How to Prevent Disc Disease

As with most things, prevention is the best medicine in regards to disc disease. If your dog is a breed that is prone to IVDD, or if your dog happens to have a longer back, ensuring it remains fit and trim can help keep extra weight and pressure off its mid-back. Talk to your vet if your are uncertain as to the best ways to control your dog's weight.

Using harnesses on walks instead of standard collars can help prevent a neck injury by reducing the pressure and strain on your dog's neck bones. This is especially true if your dog is a puller or likes to suddenly bolt after things on the leash.

Sometimes easier said than done, preventing your at-risk dog from jumping off high spots, such as the couch or bed, can also help ward off disc rupture or damage. Providing pet stairs for your dog can help it access the couch, bed, or car safely.

Disc disease can seem like a scary diagnosis, but most cases are treatable. However, should your dog show signs of severe disc disease, or develop paralysis, treat it as an emergency. The sooner treatment begins, the better your dog's chances of a full recovery.