Intervertebral Disc Disease (Slipped Disc) in Cats

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Intervertebral disc disease (IVDD) in cats is fortunately less common than it is in dogs but can be just as serious and painful a condition when it occurs. In this article, you’ll learn what IVDD is, how it occurs, and how to care for a cat with a slipped disc.

What is Intervertebral Disc Disease (Slipped Disc) in Cats?

Intervertebral disc disease is a painful condition in the back or neck that occurs when one or more of the soft, jelly–like discs that separate the vertebrae (back bones) either bulges/herniates into the spinal canal or ruptures open into the spinal canal.

The pressure of either the herniation or rupture can compress the spinal cord causing pain and a decreased or absent ability to use legs behind where the affected disc is located.

When a disc bulges into the canal (but doesn’t rupture open) this is called Hansen type II IVDD. When the disc actually ruptures and the contents of the disc spill into the spinal canal, which is usually associated with more severe signs of illness, this is called Hansen type I IVDD.

IVDD is considered a very common condition in dogs, seen by veterinarians on a weekly, sometimes even daily, basis. But it is fortunately considered very uncommon in cats. Even I can only think of a handful of cats that I’ve truly diagnosed as having IVDD.

Causes of Intervertebral Disc Disease in Cats

In most cases, IVDD is a degenerative condition. With age, the soft jelly-like discs between the vertebral bones can become less flexible and more fragile, making them prone to herniation or rupture.

Given how resilient and flexible cats are, trauma alone is rarely a cause for IVDD, though in a cat that is predisposed even a mild tussle with another cat at home or aggressive play may bring on an episode.

There are some mixed opinions on whether there are any breed predispositions for IVDD. Because it happens so rarely in cats, it is hard to look for patterns. One study from 2001 looking at 10 cats did not find any breed predispositions at all. A more recent study from 2016 looking at 6 cats that required surgery for IVDD listed a Persian and a Himalayan as two of the six. But the other four were not pure-bred cats.

Cats do appear to be older when the disease occurs. In the 2001 study, the average cat age was about 10 years. In the surgery study, one cat was 9 years of age, two cats were 7, one was 6, and two were 3 years. Neither study found a difference in occurrence between males or females.

Breeds considered at higher risk for bone and cartilage disorders could in theory be at higher risk for IVDD, but there appears to be little evidence to support this. Breeds exhibiting this risk include dwarf breeds like the Munchkin and tailless breeds like the Manx which can have associated spinal cord and vertebral malformations.

Symptoms of a Slipped Disc in Cats

Reduced activity and lethargy can be signs of back pain in cats. Zhuralev Andrey / Shutterstock.com

Cats can be odd creatures when it comes to pain. Many are very successful at hiding pain until it is advanced. Others may show unusual signs, making it harder to pinpoint the reason.

Some subtle signs that may be seen with IVDD in cats (though these can be seen with many other disorders causing pain or discomfort in cats) may include:

• Reluctance to move
• Reluctance to jump to higher surfaces
• Reluctance to use stairs
• Lethargy
• Reduced appetite
• Irritability/aggression
• Sensitivity along the top of the back
• Signs of pain when being picked up or carried

Symptoms of a slipped disc in cats can vary widely depending on how much disc protrusion or herniation has occurred, where along the spinal cord it occurred, and on what side.

For example, a cat with a mild disc herniation may only show some vague signs of discomfort as noted above.

However, a cat with a more significant herniation or disc rupture may be in significantly more pain and we can also see what are called neurologic deficits.

Enough pressure on the spinal cord can affect nerve conduction anywhere further back and down from the injury. This can lead to issues with walking and mobility:

• Wobbling when walking
• Limping
• Weakness in one or more legs
• Inability to use one or more legs (dragging a limb)
• Inability to feel one or more legs

For example, a cat that has severe disc disease occuring in the lumbar (lower back) region may end up with a decreased or absent ability to use both back legs. If the disc injury affects more of the right side of the spinal cord, it may be only the right leg that is affected.

There appears to be some disagreement as to where along the back most cats develop disc disease. The neck and mid-back is described as one common place but in the 2001 study looking at 10 cats, the most common area was the L4-5 space which is in the lower back. In the 2016 surgery study, all six cats required surgery in the mid to lower back.

Other Conditions That Look Like IVDD

I think it’s important to include this section because we tend to see other conditions more often that resemble IVDD in cats, instead of seeing IVDD itself.

1. Feline aortic thromboembolism (FATE)/saddlethrombus

FATE is a very serious and painful condition caused when a blood clot lodges in one of the main arterial branches leading to the limbs. Usually this occurs in the back legs where the aorta divides into the left and right iliac arteries but it can also occur in one of the front legs.

FATE can resemble intervertebral disc disease because a cat may suddenly be unable to use their back legs (or may hold up or drag a front leg). The main difference between FATE and IVDD is that blood supply to the affected leg(s) has been interrupted with FATE, making the limb(s) cold to the touch. While IVDD affects nerve conduction, it does not affect blood flow.

FATE is unfortunately much more common than IVDD owing to a few common conditions increasing a cat’s risk for it. These include heart disease (HCM), hyperthyroidism, cancer, and some more serious infections.

2. Osteoarthritis (OA)

Osteoarthritis is very common in cats, especially as they get older. While most arthritis occurs in the shoulders, elbows, knees, and hips, it may also occur in the back as well. This can be especially true in overweight cats.

OA is so much more common that intervertebral disc disease may actually be misdiagnosed as OA in some cases, especially for cats presenting with a limp in only one leg. The main difference is that OA does not cause neurologic changes in limb use and function.

3. Cancer

Lymphosarcoma is the most common cancer of the spinal cord in cats and is actually a more common cause of spinal cord disease than a slipped disc. While more often affecting older cats, lymphoma can always affect a cat of any age. X-ray and ultrasound are not great at visualizing the spinal cord looking for disc disease, but in the case of lymphosarcoma, they may be more helpful in identifying it. A mass or mass effect may be visible associated with the spine, there may be actual vertebral bone appearance changes, and nearby lymph nodes in the abdomen may be affected.

Complications of a Slipped Disc in Cats

If a disc herniation or rupture is severe, the pressure on the spinal cord can cause paralysis in one more limbs. In cats that cannot feel their affected limbs, there is grave cause for concern that they may not regain function without surgery.

Carefully (and gently but firmly) pinching your cat’s toes and watching for a withdrawal reflex where they pull their leg back, is one way to make sure they can feel their affected leg(s).

Diagnosis of a Slipped Disc in Cats

Magnetic Resonance Imaging (MRI) is the test of choice to diagnose the location of a slipped disc and how bad the injury is. Levent Konuk / Shutterstock.com

1. Physical and Neurologic Exam

The first part of diagnosing IVDD in a cat is during a physical exam. In cats that are generally well behaved for a physical exam, your veterinarian will be able to locate the area where your cat is most painful.

If a back condition is suspected, your vet will conduct a neurologic exam. This can be a little challenging in cats who don’t always cooperate with the different exercises involved, but what I usually look for are deficits in a couple of reflexes. Unlike a conscious response, a reflex is an automatic action, taken by a cat without thought, and controlled by the nervous system:

General proprioception: general proprioception (also called conscious proprioception) involves the body knowing where its limbs are in space. Essentially, if you flip a cat’s foot upside down onto its top surface, the cat should immediately place it back in the correct position. If a neurologic deficit is present, proprioception may be affected with a delay or may be completely absent.

Wheelbarrow, backpedal, and hopping: these exercises involve a similar concept as proprioception. If you pick up a cat and tip them forwards so just their front feet are in contact with the ground (a wheelbarrow position) and then move them forward, their little limbs will normally move one after the other in a brisk forward placing motion.

The same goes for backpedaling where only the hindfeet are in contact with the ground and the cat is moved backwards. Hopping is where one leg is isolated to be in contact with the ground and the cat is moved to the left and right.

In cats with neurologic deficits, we look for either a very slow or delayed movement in the limb(s) being examined or complete absence where the limbs are essentially only dragging on the table or floor surface.

These tests may have to be performed several times so a vet is certain a true neurologic deficit is present and the cat is not just being uncooperative (being asked to do something that makes little sense to them).

Your vet will also look for other signs that might be suggestive of a different cause for your cat’s symptoms, like a low rectal temperature and cold limbs seen in cats with FATE.

2. X-Rays

Many veterinarians suspecting IVDD in cats may recommend checking x-rays of the spine. This is not wrong, especially as a way to rule out other causes of pain like trauma/fracture or a tumor affecting the bones in the vertebrae. But in most cases changes on an x-ray with IVDD will be very subtle or not visible. This is because the spinal cord itself cannot be seen with x-ray.

Also Read: Radiographs (X-Rays) for Cats: Costs & How It Works

Intervertebral discs that have become mineralized can be visible on x-ray and sometimes if one of them ruptures, some of that mineralized material may be seen in the spinal canal.

Disc spaces may also be narrowed in affected areas due to the disc herniating or rupturing.

However, this can be very subtle and difficult to see, requiring perfect alignment of the x-ray. Cats usually require sedation for spinal x-rays both due to their back being painful and because we don’t want any stressful activity on their part that may make a spinal condition worse.

3. CT Scan

A CT scan is essentially an x-ray but instead of one single view, involves x-rays at multiple levels or “slices” through the area being viewed. While this may be more helpful than a single x-ray view, the spinal cord still cannot be imaged adequately.

A myelogram can be performed with either x-ray or CT, where a contrast material is injected into the spinal canal to highlight the spinal cord and areas where it is affected. This is less commonly performed nowadays given the invasiveness and risk, especially in cats who have very small spinal canals. MRI has largely replaced this approach.

4. MRI

Magnetic Resonance Imaging is the most reliable and is currently the standard for diagnosing intervertebral disc disease. With MRI, soft tissues like the spinal cord and the disc material itself can be viewed, seeing exactly which intervertebral spaces are affected and how serious the herniation or rupture is.

Both CT and MRI require a short period of anesthesia to perform. This makes them more expensive procedures, especially MRI. MRI’s are typically only available through a veterinary neurologist as interpretation and the need for different contrast studies must be determined in real time.

Treatments for a Slipped Disc in Cats

Prednisolone is the most common anti-inflammatory medication used for cats with a slipped disc. luchschenF / Shutterstock.com

Treatments for IVDD can be divided into medical and surgical management. Essentially, milder cases of IVDD can be managed medically while more severe cases, especially those involving loss of limb function or sensation, are best addressed surgically.

1. Medical Management

Medical management for IVDD involves strict rest, anti-inflammatory medication, and pain medication.

Strict rest can be very difficult to achieve for cats but any efforts must be made to prevent any worsening of the existing disc herniation or rupture (or having additional areas be affected). At the least this may involve keeping your cat in a small room like a bathroom or closet. It could also mean having a small dog crate to prevent your cat from jumping on and off higher surfaces.

Antiinflammatory medication will most often be a steroid like prednisolone. In cats who cannot be orally medicated, a long-acting steroid injection may be considered (but benefits should always outweigh the potential risks especially for any overweight cat or cat that may have heart disease). Non-steroidal anti-inflammatories can be used in cats for short periods, but IVDD usually requires length of treatment longer than is considered safe for NSAID use in cats.

Common pain medications include buprenophine and gabapentin. Buprenorphine has better activity in the short-term for painful cats while gabapentin can have a better (and more cost-effective) long-term effect, especially for nerve-related pain.

Gabapentin can also be useful to provide some sedation for a cat needing activity restriction.

Once the pain and inflammation are effectively treated, inappetent cats often start to eat again, but appetite stimulants may also be recommended, at least initially.

Depending on the degree of the intervertebral disc disease, medical management can take at least 4-6 weeks, sometimes longer. The biggest downside is that a cat may escape their strict rest confinement or a cat owner may grow tired of having a confined cat. Any quick resurgence of activity can lead to reinjury.

2. Surgery

Surgery is not always needed, but is necessary in cases where a ruptured disc has led to loss of limb sensation. If not addressed quickly, paralysis of the affected limb(s) may be permanent.

The type of surgery performed in the mid to lower back is called a hemilaminectomy. In the neck, it is called a ventral slot procedure.

Surgery is usually not performed without MRI imaging prior. The surgeon must know the exact location of the affected disc to minimize surgical time and increase safety.

When pursued quickly, the outcomes for intervertebral disc surgery are usually very good. The compressive disc material is removed. While healing can still take a couple of weeks, affected cats will have a quicker return to full function than without and will be at a lower risk for reinjury.

Cat Care Tips

Caring for a cat with a slipped disc has its challenges, especially when you need to keep a kitty activity restricted for weeks. Here are some tips.

• Cats sleep 18 hours a day on average, so it’s helpful to remember that they are well-adapted to bed rest. Feeling “bad” they must be confined to rest can lead to poor decisions to let a cat out for a “brief stretch” leading to reinjury.
• If activity restriction needs to be very strict (such as when neurologic deficits or any paralysis is present) a small pet crate large enough for a bed, litterbox, and food/water bowls can help to ensure there are no accidents from jumping, running, etc.
• Stick to the period of activity restriction your vet recommends. Once back pain starts to improve on medications and a cat looks more comfortable, it may be tempting to drop the activity restriction. But remember, even one jump up or down can reintroduce the injury or make the original one worse and you’ll be back at square one again.
• Your vet will want to check on your cat’s progress periodically. Video calls can be helpful early on so as not to risk reinjury, especially if your cat is difficult to get into a carrier. After a couple of weeks, an in-person check should be done to reassess any previous neurologic deficits.
• Cats can hide pain quite well, making it tempting to reduce medication dosages or frequency at home on your own. But it’s important to follow your veterinarian’s medication instructions and not to reduce dosages or discontinue any therapy earlier than directed.
• If your cat has any hind limb paralysis as part of their disease, make sure to keep a close eye on urination and defecation at home.
• If your veterinarian indicates your cat is overweight, take any recommendations for weight loss seriously. Weight loss can be a crucial part of reducing the risk of recurrent injury.
• If at any time during your cat’s recovery, you feel your cat’s signs are worsening, take them to the vet immediately for a reevaluation.

Prevention of a Slipped Disc in Cats

If a cat is overweight or obese, they may be at higher risk for a slipped disc and back pain. Andriy Blokhin / Shutterstock.com

Given that so few cats get diagnosed with a slipped disc, it’s hard to know how to prevent the occurrence. It is considered a degenerative condition and so even if there is no known breed predisposition, a cat may still be genetically predisposed.

Weight may certainly play a factor. While being overweight or obese doesn’t cause degeneration of intervertebral discs, the extra weight will put more stress on the back and contribute to herniation or rupture in cats at risk. For more information, see our article on how to determine if your cat is overweight.