There are many causes of hind leg weakness in dogs and the exact cause is often difficult to establish – even for veterinarians.

Senior dogs often show weakness in their back legs. This usually develops gradually over time. Dogs tend to get aches and pains as they get older – just like we do.

Some causes of hind leg weakness in dogs can however strike at any age. Sudden weakness, or even paralysis, can be especially frightening. If this happens you should consult your veterinarian without delay.

Dog hind leg weakness shows up in many different ways. The signs depend partly on your dog’s build, strength, age or nature. At other times, the specific signs will be related to the cause.

Signs of Hind Leg Weakness in Dogs

Depending on the severity and the root cause of hind leg weakness, you may notice one or more of the following:

• Difficulty getting up
• Weakness/trouble standing on back legs
• Stiffness in joints and legs
• Signs of pain in the back legs
• Reluctance to be active
• Lack of balance and coordination
• Instability (wobbly back legs)
• Staggering
• Paralysis

If you notice any of these signs of you should also look out for any other abnormal physical signs or changes in your dog’s behavior.  This could include swelling of the back legs, muscle wasting, incontinence, licking their legs or joints, and seizures. 

When you take your dog to the vet because you’ve noticed back leg weakness you’ll need to give a complete history. This will help them to diagnose the cause of the dog hind leg weakness.

Causes of Hind Leg Weakness in Dogs

Most of the different causes are related to the dog’s spinal column, spinal cord or the nerves that supply the back legs. They can be divided into broad categories.

• Injury to the spinal cord or nerves supplying the hind legs. This is generally the most obvious cause of dog hind leg weakness.
• Degenerative and other diseases. These conditions mostly have a genetic link and develop over time. The most common is degenerative myelopathy. Dogs can also develop “slipped” disks and arthritis.
• Tumors and cancer. Dogs can develop cancerous tumors in their backs, even very young dogs.
• Infectious diseases. A number of microorganisms and parasites can cause inflammation or paralysis in a dog’s spinal cord, disks or nerves.This includes roundworms and some species of ticks.
• Nutritional disorders. Vitamin B1 (thiamine) deficiency (most often diet-related), can cause hind leg weakness in dogs. There are usually other signs as well.
• Hormonal imbalances. Cushing’s disease, characterized by an excess of “fight-and-flight” hormones, has back legs weakness as one of the symptoms.
• Poisoning. Toxins from plants or pesticides, after skin contact or eating poisoned prey, can cause paralysis, usually starting with the hind legs.
• Reduced blood supply. When the blood supply to the dog’s spinal cord is blocked it can cause hind leg weakness or even paralysis (for example from a fibrocartilaginous embolism - FCE).

With so many potential causes of hind leg weakness you can see why it’s important to consult your vet for a diagnosis. We’ll now have a more detailed look at a few of the common causes.

Sudden hind leg weakness in dogs

Dog hind leg weakness from some of the above-mentioned causes can be treated effectively. However, the success of treatment often depends on how soon it’s started – especially in the case of sudden hind leg weakness.

A spinal injury usually causes sudden dog hind leg weakness, which is also severe and painful. Take your dog to the vet if you notice these signs – you might not be aware that your dog has hurt himself while playing or from a fall.

With cage rest, and medication for swelling and pain, full recovery from a spinal injury is often possible. Sometimes surgery is necessary. (A note from Vital Vet: rehabilitation and physical therapy as well as body work done by rehab professionals are very helpful in treating hind leg weakness from spinal injury - contact a rehab professional near you or one of our Pet Experts via video consult from home).

A condition that vets often see in spring – following on a burst of activity after the quiet winter months – is a “spinal stroke” or fibrocartilaginous embolism (FCE). One minute your dog is happily jumping up in the air to catch a stick and the next minute they yelp and are unable to walk.

This condition is caused by small pieces of cartilage from the spine breaking off and blocking blood flow to the spinal cord. Any pain usually goes away quickly and, with early treatment, there is often a near full recovery.

Sometimes your dog could be quite fine when he beds down for the night but the next morning he’s unable to use his back legs and seems to be in pain. The reason could be a “slipped” or herniated disc. Dogs from as young as a year old can experience this condition.

Tick paralysis from neurotoxins injected into the bloodstream is another condition which could cause sudden dog hind leg weakness.

When dogs become weak in their back legs gradually over time it’s mostly linked to genetics and this usually happens in older dogs.

Hind leg weakness in senior or old dogs

Canine Degenerative Myelopathy, also referred to as DM, is the most common reason why older dogs develop progressive weakness in their back legs. It eventually leads for loss of bladder control and paralysis.

The condition is caused by a gene mutation. It leads to a gradual degeneration of the spinal cord. Communication between the brain and the nerves supplying the lower body is lost. DM is similar to ALS and Lou Gehring disease in humans.

The problem usually starts when the dog is around 9 years old and there aren’t any treatments that can reverse the condition (A note from Vital Vet: rehabilitation and physical therapy can help to maintain muscle strength and slow the disease process - contact a rehab professional near you or one of our Pet Experts via video consult from home).  DM was originally thought to be a condition mainly in German Shepherds, but it’s actually seen in many different dog breeds.