What is ... ?:

The peripheral nerves make up the part of the nervous system which is outside of the brain and spinal cord (the central nervous system). Neuropathy is a general term meaning dysfunction of some part of the peripheral nervous system. The clinical signs that are seen with peripheral neuropathies include weakness or paralysis, reduced or absent muscle reflexes, reduced or absent muscle tone, and a loss of muscle mass. There may also be loss of pain sensation, which is the primary finding in sensory neuropathies and leads to self-mutilation.

Peripheral neuropathies include Dancing Doberman disease, Rottweiler distal polyneuropathy, giant axonal neuropathy, idiopathic polyneuropathy (Alaskan malamute), hypertrophic neuropathy, boxer progressive axonopathy, sensory neuropathy, laryngeal paralysis -polyneuropathy complex (Dalmatian) Megaesophagus is a common complication in several breeds.Those peripheral neuropathies believed to be inherited are listed below.

Abnormality	Breeds affected (RARE)	Inheritance	Clinical features
Dancing Doberman disease	Doberman pinscher	unknown	develops between 6 months and 7 years of age; tendency to flex and straighten 1 and then both hind limbs while standing; gait remains normal while walking; may eventually develop weakness in hind legs, and be reluctant to stand; very slowly progressive - affected dogs remain acceptable pets for many years
Distal sensorimotor polyneuropathy	Rottweiler	AR	weakness develops in the hind legs in adult dogs, gradually (over about 12 months) all 4 legs are affected; there is pronounced muscle wasting
Giant axonal neuropathy	German shepherd	AR	signs appear by 14 to 16 months; weakness in hind legs, loss of muscle tone and mass; bark is lost, dog may have fecal incontinence; by 18 - 24 months, there is weakness in all 4 limbs, and loss of normal function of esophagus (megaesophagus)
Hereditary or idiopathic polyneuropathy	Alaskan malamute	AR	weakness in hind legs by 6 to 14 months; gradually affects front legs too; some dogs recover strength for several years until problem reoccurs +/- megaesophagus
Hypertrophic neuropathy	Tibetan mastiff	AR	weakness in hind legs by 2 months; quickly progresses to all 4 lim
Laryngeal paralysis -polyneuropathy complex	Dalmatian	AR	signs by 2 to 6 months; mainly respiratory difficulty (coughing, loud breathing); also weakness of all limbs, loss of muscle mass; megaesophagus common; death or euthanasia within 6 months of diagnosis, due to aspiration pneumonia
Progressive axonopathy	boxer	AR	lack of coordination in hind end develops before 6 months of age; affects all limbs by 1 year; affected dogs function acceptably for months or years
Sensory neuropathy	long-haired dachshund, English pointer (see acral mutilation syndrome)	AR	signs by a few months of age; loss of pain sensation leads to self-mutilation

For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

In most of these conditions, the first sign you will see is weakness in your dog's hind end. S/he may stop to rest after short periods of exercise and have trouble climbing stairs. This weakness gradually affects the front legs as well. There may be coughing because the muscles around the larynx are weakened.

In some breeds, megaesophagus is a problem. This is a chronic dilation (expansion) of the esophagus which occurs because of loss of normal muscle tone and function, so that swallowing can not occur normally. Affected dogs regurgitate undigested food after meals, and may develop aspiration pneumonia due to inhalation of food particles or other foreign matter.
Weakness is not seen with sensory neuropathies, although dogs may eventually develop a lack of coordination. The lack of pain sensation leads to chewing at the feet in the English pointer, and at the penis in affected male dachshunds.

How is ... diagnosed?:

Diagnosis is based on a thorough neurological examination, the absence of abnormalities on routine diagnostic tests, and the progressive nature of these conditions. A muscle biopsy and electronic testing of nerve conduction potentials (an electromyogram) in affected muscles will help with the diagnosis.

How is ... treated?:

There is no treatment for these conditions.

For the veterinarian:

Typical are lower motor neuron signs of paresis or paralysis, decrease or loss of spinal reflexes, hypotonia, and neurogenic muscular atrophy.

Dancing doberman disease: Dogs often develop exaggerated hindlimb reflexes and proprioceptive deficits. Atrophy is most evident in the gastrocnemius, where histological and electromyographic abnormalities are most marked.
Rottweiler distal polyneuropathy: There is pronounced neurogenic atrophy in skeletal muscle biopsies, and electromyographic abnormalities in distal appendicular muscles.
Giant axonal neuropathy and hereditary polyneuropathy: Distal limbs are most affected (for electromyography and muscle biopsies).
Laryngeal paralysis -polyneuropathy complex of dalmatians: Electromyelographic and histological abnormalities are found in distal appendicular muscles and in laryngeal and facial muscles.
Progressive axonopathy in boxers: Diagnosis is based on breed, age of onset, slow progression of clinical signs (ataxia, proprioceptive deficits, loss of patellar reflexes without muscle atrophy), and electrophysiologic abnormalities.
Sensory neuropathies: In dachshunds there is subtle ataxia, loss of proprioception, loss of pain sensation over the whole body, urine dribbling and penile self-mutilation. Sensory nerve potentials are reduced or absent. Male dogs may need to be muzzled to prevent self-mutilation, but can otherwise live fairly normally.
In English pointers there is pain loss in the distal limbs and severe acral self-mutilation, without proprioceptive loss or ataxia. The prognosis is poor because of the potential for osteomyelitis. [See acral mutilation syndrome.]

Breeding advice:

Affected animals, their parents and siblings (suspect carriers) should not be used for breeding. For both progressive axonopathy in boxers and hereditary polyneuropathy in the Alaskan malamute, breed clubs in the UK and Norway have initiated comprehensive control programmes to remove known and suspected carriers from breeding, and this has greatly reduced the occurrence of these conditions.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Ackerman, L. 1999. The Genetic Condition: A Guide to Health Problems in Purebred Dogs. pp 141-142. AAHA Press. Lakewood, Colorado.

Braund, K.G. 1995. Peripheral nerve disorders. In S.J. Ettinger and E.C. Feldman (eds.) Textbook of Veterinary Internal Medicine, pp. 701-726. W.B. Saunders Co., Toronto.

Braund, K.G., Shores, A., Lowrie, C.T., et al. 1997. Idiopathic polyneuropathy in Alaskan malamutes. Journal of Veterinary Internal Medicine. 11(4): 243-249.

Braund, K.G. 1995. Laryngeal paralysis-polyneuropathy complex in young dalmation dogs. In J.D. Bonoguara and R.W. Kirk (eds) Kirk's Current Veterinary Therapy XII Small Animal Practice.pp. 1136-1140. W.B.Saunders Co., Toronto.

laryngeal paralysis -polyneuropathy complex (dalmatian)

Peripheral neuropathies