Coonhound Paralysis (Polyradiculoneuritis) in Dogs

Polyradiculoneuritis (PRN) is a general term for cases where the immune system attacks nerve cells in the limbs, leading to weakness and paralysis in the affected legs. Coonhound paralysis is a specific form of PRN associated with a reaction to racoon saliva.

All forms of PRN are rare in dogs. Most cases resolve but require intense rehabilitation and supportive care. Severe cases may lead to paralysis of the respiratory muscles, which is life threatening.

Symptoms vary depending on the severity of the condition. Severe cases affect the respiratory system and can be fatal. Symptoms usually progress rapidly for the initial 7-10 days of the disease, before remaining static then gradually improving. Improvement usually starts within 3 weeks of onset. Dogs initially show symptoms of a stiff-legged gait, which progresses to hind limb weakness, hind limb paralysis, and finally paresis of all four limbs.

PRN is the most common form of peripheral neuropathy seen in dogs, but is overall a rare condition. Coonhounds and other hunting dogs in the United States have a higher risk, due to increased exposure to raccoons. The prognosis for survival is good, but affected dogs require long term care and sometimes do not recover completely. Suspected cases of PRN require urgent veterinary attention.

The underlying disease process of most cases of PRN is unknown. Coonhound paralysis is a specific type of PRN which is linked to an immune reaction to raccoon saliva.

Rare cases are linked to possible vaccine reactions, but the association has not been proven and cases remain rare. Chronic forms of polyradiculoneuritis have also been identified, and are characterized by repeated episodes of weakness or paralysis.

Dogs with polyradiculoneuritis may also develop facial nerve paralysis, with symptoms such as drooping of the ears, inability to blink, or drooping of the lip.

Diagnostic tools include

• Physical examination
• Neurological examination
• Electromyography
• Nerve stimulation testing
• Spinal tap
• Bloodwork

Treatment primarily focuses on supportive care while dogs recover. Treatments include:

• Regular rotation or movement of recumbent dogs to prevent pressure sores
• Assisted toileting
• Massage and physical therapy to reduce muscle atrophy
• Assisted feeding
• Mechanical ventilation in severe cases
• Frequent bathing to reduce urine scalding and fecal contamination

Specific treatments have not been proven, but some patients may benefit from immunoglobulin therapy.

Recovery from PRN is a slow process. Most cases begin to improve 3 weeks following initial presentation and recover within 2-4 months. Dogs with rapidly progressing symptoms have a poorer prognosis, due to the risk of respiratory muscle paralysis. Dogs require close monitoring during the recovery period to quickly identify any complications, such as urine scalding, urinary tract infections, or pressure sores. Some cases have incomplete recovery with ongoing muscle atrophy and weakness. Recurrence is possible but rare. Hunting dogs that contract coonhound paralysis should be retired from hunting.

Prevention of most types of PRN is not possible as the underlying disease mechanism is not understood. Hunting dogs that contract the disease should not be used for hunting again to prevent recurrence.

PRNs are rare conditions in dogs. Of the different triggers of PRN, Coonhound paralysis is the most common.

• Regular movement prevent pressure sores
• Assisted toileting
• Massage to reduce muscle atrophy
• Assisted feeding
• Mechanical ventilation in severe cases
• Frequent bathing