17 Causes of Hind-Leg Weakness in Dogs

If your dog's back legs are giving out, you are likely concerned about it. Hind-leg weakness in dogs can have multiple causes. Veterinarian Dr. Ivana shares several possible causes and the importance of seeing the vet for diagnosis and treatment.

Witnessing a dog's back legs giving out is one of the most distressing sights imaginable for many dog owners.

Sensations of helplessness pour in as you watch your companion who has always been by your side suddenly become wobbly, their back legs giving out, causing them to barely be able to stand.

This sudden loss of mobility is a concerning sight and you may be unsure about how to help your furry friend.

Once your dog is back to standing up and walking, your next thought is likely what happened? And how can I prevent this problem from happening again?

In this article, veterinarian Dr. Ivana Crnec, a licensed veterinarian graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia, will discuss several of the most common causes of a dog's back legs giving out.

Why Are My Dog's Back Legs Giving Out?

Hind leg weakness in dogs is a rather common issue. The dog’s back legs support the dog's weight and enable mobility. Therefore, even general weakness is likely to first become apparent in the hind legs. Following is a list of some potential causes of rear leg weakness in dogs.

1. Osteoarthritis (OA)

Canine osteoarthritis is a common condition in which the joint surfaces wear off, resulting in pain and impaired mobility. It is more common in older dogs, but it is also seen among young dogs and adults.

Causes: Osteoarthritis is usually caused by constant wear and tear of the joint surfaces (which occurs with age). However, it can also be caused by orthopedic issues (dysplasia, joint fractures) and infections (Lyme disease).

Treatment: There is no specific treatment. The goal is to manage the pain and prevent further joint damage (joint supplements).

2. Hip Dysplasia

Hip dysplasia is an orthopedic condition in which the head of the femur (thigh bone) and the pelvic socket (acetabulum) grow at different rates. The end result is joint incongruency that causes pain and limits mobility.

Causes: Hip dysplasia is a genetic condition and is common in certain breeds. Predisposing factors include fast growth, an unbalanced diet, inadequate exercise, and weight issues.

Treatment: Mild cases of hip dysplasia can be managed with joint supplements, while more severe cases usually require surgical treatment.

3. Patellar Luxation

Patellar luxation is when the kneecap (patella) shifts out of its normal position (which is on the groove of the femur or thigh bone).

Causes: Patellar luxation in dogs can be congenital or acquired. Cases of luxated patellas are usually the result of trauma.

Treatment: Depending on the severity, dogs with luxated patellas can be treated with medications or surgically managed.

4. Degenerative Myelopathy (DM)

Degenerative myelopathy is a slowly progressing condition affecting the spinal cord. DM causes weakness and loss of coordination. It is particularly common in German Shepherds.

Causes: Degenerative myelopathy is genetic—caused by a mutation in the gene responsible for coding a protein (called superoxide dismutase) that destroys free radicals.

Treatment: Sadly, there is no treatment for degenerative myelopathy. The focus is on providing supportive care and improving the dog’s quality of life.

5. Discospondylitis

Discospondylitis is an extremely painful infection of the intervertebral discs. The condition is challenging to diagnose and requires prolonged treatment.

Causes: The infection is usually caused by bacteria, most often Staphylococcus pseudointermedius or S. aureus. Other bacteria (Escherichia coli) and fungi (from the Aspergillus family) can also be culprits.

Treatment: The treatment includes a long use of antibiotics. By long use, we mean at least six to eight weeks.

6. Lumbosacral Stenosis

Lumbosacral stenosis is a condition that develops when the spinal canal narrows in the lumbosacral region. The narrowing pressures the spinal nerves.

Causes: Spinal canal narrowing can be caused by arthritis, disc infections, trauma, intervertebral disc herniation, spinal tumors, or congenital deformities.

Treatment: Dogs with lumbosacral stenosis require a mix of drugs, such as muscle relaxants, anti-inflammatory agents, and neuropathic meds.

7. Wobbler Syndrome

Wobbler syndrome is a specific condition affecting the cervical spine (neck) of large and giant breed dogs.

Causes: Wobbler syndrome can be caused by a small spinal canal coupled with disk herniation or narrowing of the spinal canal due to bone deformities. The first cause is common in Dobermans.

Treatment: There are two treatment options—medications and surgery. Deciding which treatment is best depends on the severity of the condition.

8. Myasthenia Gravis (MG)

Myasthenia gravis is a neuromuscular disorder. It starts with hind leg weakness and progresses to general weakness.

Causes: Myasthenia gravis can be hereditary (if the dog is born with a small number of acetylcholine receptors) or acquired (due to a faulty immune system).

Treatment: Dogs with MG require two types of medication—acetylcholinesterase inhibitors and immunosuppressive drugs. Some dogs need these meds for life, and others go into remission after a certain timeframe.

9. Vestibular Disease

Also known as “old dog vestibular syndrome,” this is a non-progressive and sudden loss of coordination. As the name suggests, it is more common in older dogs.

Causes: Vestibular disease can be caused by ear problems (infections and ear drum perforation), trauma, tumors, etc. If the exact cause is unknown, the issue is called idiopathic vestibular syndrome.

Treatment: The treatment depends on the exact cause. If the cause cannot be determined, the dog is provided with supportive care until the balance returns.

10. Exercise Induced Collapse (EIC)

Exercise induced collapse in dogs is a specific condition that starts with hind leg weakness and culminates in collapse. As expected from the name, it is triggered by strenuous exercise.

Causes: Exercise induced collapse is an inherited problem caused by DNM1 (dynamin 1) gene mutation.

Treatment: There is no specific treatment for exercise induced collapse in dogs. However, episodes can be prevented by avoiding excess physical activity.

11. Spinal Tumors

Spinal tumors in dogs are relatively rare. If they develop, they are more common in large and giant breed dogs. Spinal tumors can affect the soft tissue or bony parts of the spine.

Causes: The exact cause of spinal tumors in dogs is unknown. What is known is that they can be primary (developing from or within the spine) or secondary (metastasis from tumors on other parts of the body).

Treatment: As with all tumors, the treatment depends on the type and location. Possible treatment options include surgery, chemotherapy, radiation therapy, or a combination of all.

12. Intervertebral Disc Disease (IVDD)

Intervertebral disc disease (IVDD) is a spinal condition in which a disc herniates. The condition starts as an orthopedic issue, but when the herniated disc starts pressuring the spinal cord, it evolves into a neurologic problem.

Causes: The most common cause of IVDD is trauma. However, the condition is more common in chondrodystrophic breeds like Dachshunds, Basset Hounds, and Corgis.

Treatment: Mild cases of IVDD can be managed with medications (steroids and anti-inflammatory drugs) and rest. Severe cases require surgery.

13. Cardiac Problems

Various heart problems can trigger hind leg weakness. Possible issues include congestive heart failure, cardiomyopathy (heart muscle disease), arrhythmias, pericardial effusion (fluid accumulation in the heart sac), and heart tumors.

Causes: Heart issues can be congenital (the result of birth defects affecting the heart) or acquired (wear and tear), infections, and injuries.

Treatment: The treatment depends on the exact cause and the severity of the problem.

14. Heartworm Disease

Heartworm disease is a serious parasitic infection in dogs that can cause lung problems, organ damage, and heart failure.

Causes: Heartworm disease in dogs is caused by a parasite—more specifically, a worm called Dirofilaria immitis. The parasite is transmitted via mosquito bites.

Treatment: The mainstream treatment for heartworm disease is an injectable medication called melarsomine dihydrochloride. There is also some progress in the field of surgical removal of worms, but the procedure is still dangerous.

15. Hypothyroidism

Hypothyroidism is an endocrine problem in which the dog’s thyroid gland does not produce enough thyroid hormones. Hypothyroidism in dogs causes general weakness.

Causes: Hypothyroidism is caused by lymphocytic thyroiditis (immune-mediated condition) or thyroid gland atrophy. The first cause is more common.

Treatment: Dogs with hypothyroidism require lifelong medication with synthetic thyroid hormone replacement drugs. At the moment, there are two such meds that are FDA-approved and available with a veterinary prescription.

16. Addison’s Disease

Addison’s disease develops when the adrenal glands do not produce adequate amounts of hormones, causing overall weakness, vomiting, diarrhea, weight loss, and increased thirst and urination.

Causes: The most common cause of Addison's disease is immune-mediated destruction of the adrenal gland. Other possible causes include infection, trauma, and cancer.

Treatment: The treatment is based on an injectable medication that replaces the missing aldosterone. Depending on the patient, the medication is given every three to four weeks.

17. Metabolic Conditions

Finally, many metabolic conditions can result in hind leg weakness in dogs. Some of the most common ones are anemia (low red blood cells), hypoglycemia (low blood sugar levels), and hypokalemia (low potassium levels).

Each of these issues can be triggered by a myriad of issues and requires a specific treatment approach. These metabolic problems are easy to diagnose (all it takes is a blood test). However, the treatment depends on the exact cause.

How Is Hind Leg Weakness in Dogs Treated?

As seen, there are many causes of hind leg weakness in dogs, each requiring different treatments. Some causes are more serious than others and require more aggressive management.

Regardless of the cause, it is important to see your vet as soon as you notice your dog’s back legs are giving out.

Even if the cause of hind leg weakness is not dangerous, it may be painful and impact the dog’s quality of life. Also, in most cases, the sooner a treatment is initiated, the better the outcome.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2023 Adrienne Farricelli