Polyneuropathy affects the nerves found outside the brain and spinal cord, known as the peripheral nerves and can be inherited or acquired, developing at a later point in the dog’s life.

Inherited polyneuropathy is usually the result of three main causes. The first is spinal muscular atrophy, which occurs when the muscles of the spine shrink and deteriorate. The second is demyelization, which causes the destruction of the myelin (protective sheath covering the nerves. The third cause is lysosomal storage diseases which are inherited enzyme deficiencies that prevent the body from performing normal metabolic functions.

In acquired polyneuropathy, the disease is acquired later in life, usually caused by diabetes, hypothyroidism or autoimmune disorders like lupus. Other conditions that cause inflammation of the muscles, joints and kidneys can also cause polyneuropathy as can the infectious organism known as neospora canis.

Most, if not all of these disorders, result in muscle weakness or paralysis, degeneration of muscle tone, muscle mass and muscle reflexes. Affected dogs will often display head tremors, seizures, and an unsteady gait and may injure themselves due to a loss in their ability to feel pain. Symptoms for inherited neuropathy generally start when the puppy is around six months and can progress slowly over time. In acquired cases the disease can appear at any age and symptoms develop depending on the individual and he cause.

Diagnosis can involve a number of blood, nerve, and muscle tests. Unfortunately, the inherited forms are incurable, and treatment is therefore focussed rather on making the dog comfortable. Acquired neuropathy can be treated based upon the specific cause with immune-suppressing drugs.