Metabolic neuropathies in animals are diseases of the peripheral nerves caused by metabolic disturbances, such as diabetes mellitus or hypothyroidism. Treatment is directed at the underlying cause.
Diabetic Neuropathy in Dogs and Cats
Diabetic neuropathy, an uncommon complication of diabetes mellitus, can occur in both cats and dogs but is rare in dogs. Several pathophysiological mechanisms have been proposed; however, prolonged hyperglycemia seems to be the important underlying factor.
Clinical signs of diabetic neuropathy include weakness, ataxia, and muscle atrophy. Affected cats often have unilateral or bilateral tibial nerve dysfunction, which characteristically produces a plantigrade stance.
Diagnosis is based on clinical findings, laboratory evidence of diabetes mellitus, and nerve biopsy results. Pathological findings in nerves include demyelination (with evidence of associated remyelination) and axonal degeneration.
The prognosis for patients with diabetic neuropathy is guarded; however, partial or complete recovery can occur with insulin therapy.
Hypothyroid Neuropathy in Dogs
Hypothyroid neuropathy is a potential complication of hypothyroidism in dogs. Mature dogs, especially large-breed dogs, are predisposed.
In cases of hypothyroid neuropathy, several clinical syndromes have been reported (1), including the following:
tetraparesis with proprioceptive deficits and hyporeflexia
vestibular dysfunction
laryngeal paralysis
In some dogs with hypothyroid neuropathy, classic clinical signs of hypothyroidism (eg, obesity and dermatopathy) are absent, and neurological dysfunction is the only clinical sign of illness.
Pearls & Pitfalls
|
Pathological findings in peripheral nerves include demyelination (with evidence of associated remyelination) and axonal degeneration. The pathophysiological basis of hypothyroid neuropathy is poorly understood, and some affected dogs with motor deficits might also have myopathy.
Diagnosis is based on clinical features, laboratory assessment of thyroid function, and response to thyroxine supplementation.
In some dogs, clinical signs of hypothyroid neuropathy resolve within several months after starting thyroxine replacement therapy.
For More Information
Neurologic Manifestations of Hypothyroidism. MSPCA-Angell.
Also see pet owner content regarding metabolic disorders of the peripheral nerves in dogs and cats.
References
Jaggy A, Oliver JE, Ferguson DC, Mahaffey EA, Glaus T Jr. Neurological manifestations of hypothyroidism: a retrospective study of 29 dogs. J Vet Intern Med. 1994;8(5):328-336. doi:10.1111/j.1939-1676.1994.tb03245.x
