Acute Polyradiculoneuritis (Coonhound Paralysis)

Acute polyradiculoneuritis is a widespread disorder of the peripheral nervous system with a sudden onset. The brain and spinal cord comprise the central nervous system, whereas the nerves leaving the spinal cord comprise the peripheral nervous system. It is a disease that causes damage to the nerves themselves, as well as to the myelin, which is a specialized substance that surrounds many nerves and allows for rapid transmission of nervous impulses.
The cause of polyradiculoneuritis is unknown, but it is believed to be an immune mediated or autoimmune process, which is associated with inflammatory cells (white blood cells) attacking the nerves. The immune system normally protects against infection by attacking organisms that are foreign to the body. In immune mediated diseases, the immune system targets and destroys its own cells, in this case the nerves.

This is the most common inflammatory peripheral nervous disorder in dogs.

It is most commonly seen in hunting dogs following exposure to raccoons, hence the alternative name of coonhound paralysis. There are no specific breed or sex predispositions. It can also be seen in dogs without previous exposure to raccoons. Adult animals are generally affected. A similar disease process has been described in the cat, but this is very rare.

What to Watch For

Weakness starting in the hind legs and progressing to all legs

Weak bark

Development of severe weakness

Total inability to stand

Shallow breaths or difficulty breathing

Diagnosis

Complete history and physical exam

Neurologic exam

Complete blood count (CBC)

Biochemical profile

Urine analysis

Electrodiagnostic testing. This evaluates the electrical activity in the nerves and muscles and assesses their function.

Cerebrospinal fluid (CSF) tap. The CSF is the fluid that bathes the brain and spinal cord. This can be collected for analysis.

Arterial blood gas (ABG). This evaluates respiratory function.

Treatment

Supportive care, including appropriate bedding

Physical therapy of the limbs

Respirator if respiratory paralysis occurs

Home Care and Prevention

Continued supportive care. Recovery may take weeks to months. The affected dog may require assistance with eating and drinking. Physical therapy is necessary several times a day and the dog should be kept clean.

Avoid exposure to raccoons. Dogs that have had one bout of polyradiculoneuritis may develop it again, so it is imperative to avoid re-exposure in these cases.