What causes sudden hind leg weakness in dogs

Noticing your dear old dog’s back legs collapsing can be heartbreaking for you and distressing for your pup. Integrative veterinarian, Dr. Julie Buzby, shares six reasons why an older dog’s back legs might sometimes collapse and what you can do about it.

If you have ever been lucky enough to share your home with senior dogs, you know that along with their greying muzzles, an affinity for naps, and boundless love can come certain health issues. Just like with people, older dogs can slow down a bit, and have some trouble with their joints. One of the more common conditions I treat in my older patients, especially in large breed dogs, is hind leg weakness or even collapse.

Why do a dog’s hind legs collapse?

There are a variety of reasons why a dog might struggle to support his or her weight in the hind end. Some of them happen very slowly. Others may occur in a matter of minutes or hours. Here are six conditions that may be the underlying reasons for a dear old dog’s back legs to collapse.

1. Arthritis

While there are many health issues that can affect the strength and function of dogs’ hind legs, the most common issue I see, by far, is arthritis. Normally, healthy bony joints have layers of cartilage that help to lubricate, cushion, and protect the joint during movement. Unfortunately, cartilage is not great at healing, and with time it can erode. The breakdown of cartilage and the associated inflammation is what causes osteoarthritis. This painful condition can affect the normal function of the joints.

Arthritis may be exacerbated by previous injury or conformation issues. Dogs who have a luxating patella, hip dysplasia in dogs, torn ACL in dogs, and other orthopedic problems are at high risk for arthritis formation. However, even with no predisposing causes, many seniors will show signs of arthritis in dogs as they age.

Arthritis is especially common in large breed dogs such as:

• Labs
• Golden Retrievers
• German Shepherds
• Many other senior dogs

Osteoarthritis of the hips and knees may eventually lead to hind leg weakness. This may cause your dog to have difficulty rising or walking and you may notice his or her hind legs collapsing. Additionally, arthritis may affect the front legs, back, and other joints. This can contribute to your dog’s overall pain level and decreased mobility. Typically, the weakness and pain associated with arthritis happen gradually.

2. Intervertebral Disc Disease (IVDD)

In contrast, some other conditions can cause very sudden hind limb weakness or collapse. One of the frequent culprits is intervertebral disc disease, otherwise known as IVDD in dogs. This is especially common in smaller breed dogs, such as Dachshunds, but can happen in larger dogs as well.

Between each vertebra there are cartilage discs that cushion the backbone as a dog moves. In IVDD these discs get displaced or herniate. This puts pressure on the spinal cord since it lies directly above the discs. Dogs with mild IVDD may only have back pain or leg weakness. Sometimes the affected dog is wobbly and off balance. However, severe spinal cord compression from IVDD can lead to complete, sometimes irreversible, paralysis.

Time is of the essence for dogs with IVDD because the sooner the vet can start treatment, the better the chances of recovery. If your dog’s back legs suddenly collapse, plan on an emergency vet visit at a local pet emergency hospital or your regular veterinarian’s office. Sometimes dogs with IVDD can recover without surgery, but other cases require IVDD surgery in dogs.

3. Degenerative myelopathy

There also are some less common causes of collapse or hind leg weakness in dogs. Degenerative myelopathy (DM) in dogs is an inherited neuromuscular disease that affects some older dogs. DM is similar to Lou Gehrig’s Disease or ALS in people. It is most common in German Shepherds, Huskies, Retrievers, and Corgis.

Dogs with DM typically have a slow progression, starting with loss of coordination, weakness, dragging one or both hind legs, or knuckling in dogs. Eventually it will lead to complete hind limb paralysis. If your vet suspects DM, he or she may recommend a genetic test that looks for mutated copies of the gene SOD-1. Researchers believe that possessing two copies of the mutated gene may put a dog at risk for developing DM. However, there is still much that is not known about this devastating condition.

4. Endocrine diseases

Some metabolic conditions can lead to hind leg weakness as well. Cushing’s disease in dogs is an overproduction of cortisol by the adrenal glands. This can lead to generalized muscle weakness which is often most notable in the rear legs in dogs.

Additionally, in rare cases, dogs with diabetes mellitus may develop diabetic neuropathy. This is a condition where nerve function becomes abnormal, leading to hind leg weakness.

Hypothyroidism in dogs also has occasionally been known to cause nerve damage and muscle weakness. This may lead to laryngeal paralysis in dogs, megaesophagus, or weakness and collapse (more commonly in all four legs).

5. Acute injury

Of course, hind leg collapse can also be associated with an injury such as cruciate ligament tears (especially if both hind legs have ACL tears), spinal stroke in dogs, or trauma to the hips, spine, or pelvis. Often, these are a bit less of a mystery because you may have seen your dog get hit by a car, fall from a height, take a bad step, cry out in pain, etc.

6. Shock

This one is a bit different than the other conditions on this list, but I believe it is worth mentioning because knowing about it could save your dog’s life. Sometimes when a dog is in shock (i.e. a state of low blood pressure and poor blood circulation) he or she may become very weak or collapse. This may look like the dog is weak and collapsing in the hind end, but really he or she is weak all over. Shock can happen for many reasons, including:

Many of the medical conditions that cause shock can be fatal if not treated quickly and correctly. That’s why it is critical to get your dog to the vet as soon as possible if he or she collapses.

What other signs or symptoms should I be watching for?

Sometimes in the early stages of arthritis, IVDD, or other musculoskeletal conditions, you may not notice the hind legs collapsing yet. That is just one of the many indicators that a dog’s rear legs are becoming weak. Also, be on the lookout for:

• Difficulty rising from lying down or sitting.
• Exercise intolerance, or not wanting to walk or play as much as your dog used to.
• Stiff or abnormal gait.
• Trembling of the legs.
• Difficulty getting on and off furniture or climbing stairs.
• Signs your dog is in pain such as increased panting (or your dog breathing fast), limping, hiding, attitude changes, a lethargic dog, etc.
• Muscle atrophy/loss of muscle mass.

If you notice your dog exhibiting any of these signs, it’s always best to make an appointment to speak with your veterinarian.

What should I do if my old dog’s back legs just collapsed?

Step one is always going to be getting your dog to the vet. Hind leg collapse should be considered an emergency.

Some of the conditions, such as IVDD or shock, are more successfully treated if treatment is initiated very quickly. And at a minimum, the underlying cause of the hind limb weakness is painful in many cases. So getting your dog relief as soon as possible is a priority.

Your vet will discuss possible differential diagnoses after listening to the history you provide and performing a physical exam. The next step is diagnosis of the underlying cause. In many cases, your vet will want to get some X-rays of the back legs, spine, and pelvis. This allows him or her to see what might be going on with the bones, joints, or organs visible on the X-ray.

Additionally, your vet may also tell you that it is a good idea to run some bloodwork. This helps your vet identify or rule out some of the metabolic causes of hind leg weakness discussed. Plus, it ensures your dog is healthy enough to metabolize (i.e. break down) some of the medications we may use to treat him or her.

Just as cartilage can wear down in senior dogs, sometimes they can have some underlying kidney or liver dysfunction that isn’t physically apparent. Running baseline bloodwork before starting new medications can ensure the treatment doesn’t have the potential to make an invisible problem worse. Also, it can make it easier to compare pre-treatment and post-treatment values for monitoring purposes.

Referral to a veterinary specialist

Depending on what these tests show, your veterinarian may also recommend a consultation with a specialist. This may be a veterinary neurologist, orthopedic surgeon, internal medicine specialist, etc. These specially trained veterinarians are well equipped to handle the cases that are less straightforward or need advanced testing such as MRI or CT. Also, they can perform more complex surgical procedures such as a TPLO surgery for dogs (in the case of a torn ACL) or spinal cord decompression for IVDD dogs.

If my dog’s legs are collapsing, what are the treatment options?

As you may imagine, treatment can vary depending on the underlying cause of the hind limb weakness or collapse. Dogs with IVDD may need surgery or may be managed medically, depending on the severity. Those with metabolic diseases will have treatment tailored to the particular condition. Your vet will treat trauma and shock on a case by case basis. Unfortunately, there is no effective treatment for degenerative myelopathy in dogs. Symptomatic medical management can make some of them more comfortable, but eventually the disease does progress to complete paralysis.

Treatment options for dogs with hind leg collapse due to arthritis

Since arthritis is one of the most common reasons for hind leg collapse, we will spend a bit more time talking about how to relieve arthritis pain in dogs. For these guys and gals, multimodal treatment (i.e. combining a variety of treatments) can make a huge difference.

Weight loss

My first conversation with parents of dogs with arthritis usually has to do with weight loss. The more weight a dog is carrying, the more stress it places on arthritic joints. A lot of arthritic dogs are overweight or obese, and slimming down makes a huge difference in their quality of life. If you are wondering “Is my dog overweight?“, please talk to your vet and try out my easy method to find your dog’s body condition score. Additionally, check out my article, How to Help a Dog Lose Weight.

Medications

NSAIDs (i.e. non-steroidal anti-inflammatory drugs) can make a huge difference by reducing pain and inflammation associated with arthritis. The parents of older dogs on NSAIDs often tell me their dogs are acting like puppies again! Some dogs may also benefit from other types of pain medication such as tramadol for dogs or gabapentin for dogs. (And if your dog is on gabapentin, be sure to check out my article on gabapentin side effects in dogs).

Joint supplements

There are a variety of joint supplements for dogs on the market today that can support cartilage health and help slow the progression of arthritis. One of my favorites is Dr. Buzby’s Encore Mobility™ hip and joint supplement, and I don’t just say that because it has my name on the label.

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This amazing product combines the benefits of green lipped mussel for dogs and New Zealand deer antler velvet for dogs to reduce joint inflammation, protect and maintain joint health, promote tissue healing, and so much more. The infographic below gives you the scoop on all the benefits of Encore Mobility.

Other joint supplement ingredients that I would recommend include:

• Glucosamine and chondroitin sulfate—common joint supplement components which contain building blocks of cartilage and help decrease cartilage destruction.
• Methylsulfonylmethane (MSM)—compound which promotes new cartilage formation and has anti-inflammatory and pain-relieving properties.
• Turmeric/curcumin—popular human supplement which may have anti-inflammatory properties in dogs.
• Hyaluronic acid—main component of joint fluid which helps coat the cartilage to prevent wear and tear.
• Omega-3 essential fatty acids for dogs— anti-inflammatory substances found in fish oils and other sources.
• Cannabidiol (CBD oil for dogs)—hemp plant derivative which is not psychoactive and may provide pain relief.

Of course, always speak with your veterinarian before giving your dog any over-the-counter supplements or medications. He or she knows your dog and can recommend the product or combination of products that would be best suited for your pup.

Many arthritic dogs benefit from acupuncture, visits to the dog chiropractor, laser therapy for dogs, or working with a rehabilitation professional. I love using acupuncture and chiropractic care as part of multimodal pain management, and have seen so many dogs benefit from it. Plus, laser therapy treatment can be a great way to reduce pain and inflammation and promote tissue healing.

Physical therapy and rehabilitation are amazing for maintaining the muscle tone and range of motion that is needed for good mobility. To learn more about rehab, check out Cornell University College of Veterinary Medicine’s page on sports medicine and rehabilitation. There are a wide range of alternative therapeutic modalities available, so speak with your vet about what would be best for your dog’s condition.

Traction aids

I used to primarily recommend that people used rubber mats or non-slip rugs to help their arthritic dogs navigate on a slippery floor (and they do still have their place). But as you can read in the story of ToeGrips, that all changed once I discovered Dr. Buzby’s ToeGrips® dog nail grips.

These simple little rubber rings fit around your dog’s normal traction device—his or her toenails. Dogs typically use their toenails like cleats to grip the ground and gain traction. However, that becomes more difficult when they are on a slippery surface and have arthritis or other mobility-reducing conditions.

ToeGrips give your dog that extra bit of traction that he or she needs to walk confidently again no matter the surface. I have heard from hundreds of dog parents over the years who have been overjoyed to share how much ToeGrips have improved their dogs’ mobility and quality of life.

Household modifications

There are also a variety of ways you can help a senior dog with arthritis at home. Some of these include providing lots of soft beds, using ramps or steps to help your dog get into the car or onto your bed, and implementing an exercise plan appropriate your dog’s condition.

Gunner’s story: Why this dear old dog’s back legs collapsed

To help give all this information a furry face, let’s meet Gunner. He is an 8-year-old German Shepherd who has been my patient since he could fit in my pocket.

Unfortunately, Gunner’s dad had been noticing for the past several months that Gunner was slowing down. He had been having a hard time getting up off his bed and staggered a bit those first few steps after a long sleep. Gunner still ran around, but would sometimes bunny hop when he got going. Then one day he was out romping in the yard and his back legs completely fell out from under him.

When I saw Gunner later that morning he seemed ok. He was walking on all four legs without an obvious limp— though his hips did sway a bit. He’s a stoic guy normally, but he did wince when I put his hind legs through range of motion.

I decided to take some X-rays, which showed evidence of hip dysplasia as well as some arthritis in his left knee. (Gunner had torn his cruciate ligament and had surgery on that leg when he was two years old.) His blood tests came back normal. Especially since he is a German Shepherd, we had to think about degenerative myelopathy, but his presentation and diagnostics fit more with arthritis.

Good news for Gunner

I talked over the findings and the options with his dad. We put Gunner on a strict diet to shed some extra pounds, started a course of NSAIDs, and began acupuncture treatments. He showed improvement almost immediately!

I cautioned his dad that arthritis is usually a progressive condition so we will need to keep a close eye on Gunner to ensure his pain is managed. But right now, his dad is thankful to have his spry partner in crime back. And Gunner is much happier to have his arthritic pain and inflammation managed. He’s back to running around and finding all the trouble he can get into!

Work with your veterinarian

If like Gunner, your dog’s hind legs are collapsing, talk to your veterinarian. He or she can help get to the bottom of the problem, tell you what to expect, and formulate a treatment plan. You know your dog, and you are one of the best people to assess how things are going because you see him or her every day. So if your gut is telling you something is not right with your pup even if you aren’t seeing any collapsing, check in with your vet.

Many of the six conditions I’ve described above will require some modifications to the treatment plan over time, which is why an observant owner and a dedicated vet can make such a great team. Together you can help give your dog more good days, which is always a win!

Have your dog’s back legs ever collapsed? What was the reason and how did your dog do afterwards?

Please comment below.