Cats

Polyneuropathy

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Polyneuropathy in dogs and cats is a collection of peripheral nerve disorders that often are breed-related in these animals. Polyneuropathy indicates that multiple nerves are involved, unlike mononeuropathy. Polyneuropathy usually involves motor nerve dysfunction, also known as lower motor neuron disease. Symptoms include decreased or absent reflexes and muscle tone, weakness, or paralysis. It often occurs in the rear legs and is bilateral. Most are chronic problems with a slow onset of symptoms, but some occur suddenly.

Most common types of polyneuropathy

Birman Cat distal polyneuropathy - This is an inherited disorder. Symptoms start at the age of 8 to 10 weeks, and include frequent falling and walking on the hocks. The prognosis is poor.
Botulism - Symptoms include weakness, difficulty eating, facial nerve paralysis, and megaesophagus.
Dancing Dobermann disease - This primarily affects the gastrocnemius muscle in Dobermanns. It usually starts between the ages of 6 to 7 months. One rear leg will flex while standing. Over the next few months it will begin to affect the other rear leg. Eventually, the dog is alternatively flexing and extending each rear leg in a dancing motion. Dancing Dobermann disease progresses over a few years to rear leg weakness and muscle atrophy. There is no treatment, but most dogs retain the ability to walk.
Diabetic neuropathy
Distal symmetric polyneuropathy - Symptoms include atrophy of the distal leg muscles and the muscles of the head, and rear limb weakness. There is no treatment and the prognosis is poor.
Dysautonomia - This is primarily seen in cats. Symptoms include vomiting, depression, not eating, weight loss, dilated pupils, third eyelid protrusion, sneezing, slow heart rate, and megaesophagus. There is a poor prognosis and supportive treatment is necessary. Cats can recover, but it may take up to one year.
Giant axonal neuropathy - This is a rare disease in the German Shepherd Dog. It usually becomes evident between the ages of 14 and 16 months. Symptoms include rear limb weakness, decreased reflexes, muscle atrophy, megaesophagus, and loss of bark. There is no treatment and a poor prognosis.
Hyperchylomicronemia or hyperlipoproteinemia - This a type of hyperlipidemia that is inherited in cats. Polyneuropathy is caused by stretching or compression of nerves near bone by xanthomas, which are lipid deposits. It can cause Horner's syndrome, facial nerve paralysis, and femoral nerve, tibial nerve, radial nerve, trigeminal nerve, or recurrent laryngeal nerve paralysis.
Hypertrophic neuropathy - This is also known as canine inherited demyelinative neuropathy (CIDN) and is inherited in the Tibetan Mastiff. Symptoms usually start between the ages of 7 to 10 weeks, and include weakness, decreased reflexes, and loss of bark. There may be a poor gait or an inability to walk. There is no treatment and a guarded prognosis.
Hypoglycemia - Polyneuropathy is especially seen in conjunction with insulinoma.
Myasthenia gravis
Polyradiculoneuritis - This is inflammation of the nerve roots. The most common type is Coonhound paralysis. This is similar to Guillain-Barré syndrome in humans. Coonhound paralysis seems to be secondary to a raccoon bite, probably due to some factor in the saliva. It can happen in other breeds of dogs, also. Symptoms start 7 to 11 days after the bite, and include rear leg weakness progressing rapidly to paralysis, and decreased reflexes. Severe cases will have a loss of bark, trouble breathing, and an inability to lift the head. There is a duration of 2 to 3 months for the disease. Treatment is proper nursing care, and the prognosis is good in mild cases. Polyradiculoneuritis can also be caused by toxoplasmosis.
Rottweiler distal sensorimotor polyneuropathy - The symptoms include weakness of all four legs and decreased reflexes. The disease is gradually progressive. There is a possible treatment with corticosteroids, but the prognosis is poor.
Sensory neuropathies - These are inherited conditions in dogs and cause an inabilty to feel pain and a loss of proprioception. Self mutilation is often seen. There is no treatment, and the prognosis is poor in severe cases.
Spinal muscular atrophy - This occurs in dogs and is caused by the death of nerve cells in the spinal cord. This progressive disease has no treatment and a poor prognosis.
Tick paralysis - This occurs in dogs; cats seem to be resistant. The cause is a neurotoxin in the saliva of certain species of adult ticks. Dermacentor species predominate as a cause in North America, while Ixodes mainly causes the disease in Australia. There is a gradual onset of symptoms, which include incoordination progressing to paralysis, changed voice, and difficulty eating. Death can occur secondary to paralysis of the respiratory muscles, but in North America there is a good prognosis once the ticks are removed. Recovery is usually in 1 to 3 days. In Australia, however, it is a more severe disease with cranial nerve effects, and death can occur in 1 to 2 days.
Toxic neuropathies - The most common causes are vincristine, thallium, and lead.

References

Chrisman, Cheryl; Clemmons, Roger; Mariani, Christopher; Platt, Simon (2003). Neurology for the Small Animal Practitioner(1st ed.). Teton New Media. ISBN 1-893441-82-2
Ettinger, Stephen J.;Feldman, Edward C.(1995).Textbook of Veterinary Internal Medicine(4th ed.). W.B. Saunders Company. ISBN 0-7216-6795-3