Dog owners are always worried when they see their beloved dog's weakness in the back legs. The causes for weakness in back legs of dogs are numerous and stem from a variety of problems, some of which can be serious if left untreated. In this article, we will discuss five of the most common causes for weakness in back legs of dogs. While some may seem minor, they should not be ignored as they could lead to more serious health problems down the road.

1. Myasthenia Gravis (MG)

One possible cause of weakness in the back legs of dogs is myasthenia gravis. Myasthenia gravis is an autoimmune disorder that affects the transmission of nerve impulses to muscles.

The symptoms of myasthenia gravis can vary depending on the severity of the disorder, but they typically include weakness and fatigue. In some cases, the weakness may be so severe that the affected animal is unable to walk. Myasthenia gravis is a common cause of acquired megaesophagus in dogs in which case, you may notice your dog regurgitating its food hours after eating it.

Myasthenia gravis is most commonly diagnosed in young adult dogs, and it can be treated with medication. However, if left untreated, myasthenia gravis can lead to paralysis and even death. Therefore, if your dog is showing signs of weakness in its back legs, it is important to contact your veterinarian as soon as possible for a diagnosis.

2. Anemia (low red blood cell count)

Anemia is another common cause of weakness in the back legs of dogs. Anemia is when there is a decrease in the number of red blood cells or hemoglobin in the blood. Red blood cells are responsible for carrying oxygen to the body's tissues, and a decrease in these cells can lead to weakness and fatigue.

Anemia in dogs can be caused by many things, including blood loss, malnutrition, or certain diseases such as autoimmune diseases. If your dog has weakness in the back legs and you think anemia may be the cause, take him to your veterinarian for a checkup. Your vet can perform blood tests to confirm the diagnosis and recommend treatment options. With proper care, most dogs with anemia can recover and live healthy lives.

3. Addison's disease (hypoadrenocorticism)

Another possible cause of weakness in the back legs of dogs is Addison's disease. Addison's disease is a disorder of the adrenal glands. The adrenal glands are responsible for producing hormones that help regulate metabolism, immune system function, and blood pressure.

Dogs with Addison's disease do not produce enough of these hormones, which can lead to weakness, lethargy, and even collapse. If your dog is showing signs of weakness in its back legs, it is important to contact your veterinarian as soon as possible for a diagnosis. Addison's disease is a serious condition that can be life-threatening if not treated promptly.

4. Cardiac problems

Another potential cause of weakness in back legs of dogs is cardiac problems. The heart is responsible for pumping blood throughout the body, and if it is not working properly, the body may not receive enough oxygen. This can lead to weakness, fatigue, and even collapse.

Heart failure and arrhythmias are both examples of cardiac issues that can result in hindlimb weakness in dogs.

If you think your dog may have a cardiac problem, it is important to contact your veterinarian as soon as possible for a diagnosis. Cardiac problems can be serious and even life-threatening if not treated promptly.

5. Hypothyroidism

Sometimes, a type of neuropathy that affects the peripheral nerves occurs with hypothyroidism in dogs and may reveal itself as weakness in the back legs during exercise.

Hypothyroidism is a condition in which the body does not produce enough of the hormone thyroxine. This hormone is responsible for regulating metabolism, and a lack of it can lead to fatigue and weakness.

Hypothyroidism is most commonly diagnosed in middle-aged to older dogs, but it can affect dogs of any age. If you think your dog may have hypothyroidism, it is important to contact your veterinarian for a diagnosis. With proper treatment, most dogs with hypothyroidism can live long and healthy lives.


Weakness in back legs of dogs can be caused by a variety of things, including myasthenia gravis, heart problems, anemia, hypothyroidism, and Addison's disease. If your dog is showing signs of weakness in its back legs, it is important to contact your veterinarian as soon as possible for a diagnosis and implement a treatment strategy.