Symptoms of Back Leg Weakness in Dogs
Signs of weakness in your dog’s back legs may come on suddenly or develop slowly over a long period of time, depending on the reason for the weakness. Often, there are other signs that can help lead to a diagnosis, so take note of any physical or behavioral changes that occur. Signs of back leg weakness can include:
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.
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:
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.
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.
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.
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).
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.
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:
If you notice your dog exhibiting any of these signs, it’s always best to make an appointment to speak with your veterinarian.
Back Leg Weakness in Dogs | Wag!
What can make a dog’s back legs weak, or cause a dog’s back legs to give out?
That’s a question I had to answer recently for the anxious parents of a middle-aged Labrador Retreiver.
Murphy is your typical, eager 6-year-old Lab. He’s a happy soul whose tail is always wagging. However, this lively ball-chasing dog had woken up that morning unable walk.