Metabolic Disorders of the Peripheral Nerves and Neuromuscular Junction in Animals

Diabetic neuropathy, an uncommon complication of diabetes mellitus Diabetes Mellitus in Dogs and Cats Diabetes mellitus is a common endocrine disease in dogs and cats, occurring in about 1 of every 300 patients. Clinical signs reflect hyperglycemia with resultant glycosuria. Diagnosis is made... read more is seen in cats and rarely dogs. Signs include weakness, ataxia, and muscle atrophy. Affected cats often have unilateral or bilateral tibial nerve dysfunction, evident as a plantigrade stance. Several pathophysiologic mechanisms have been proposed, but prolonged hyperglycemia seems to be the important underlying factor. Pathologic findings in nerves consist of demyelination with remyelination, axonal degeneration, or both. Diagnosis is based on clinical findings, laboratory evidence of diabetes mellitus, and nerve biopsy. The prognosis is guarded, but partial or complete recovery can occur with insulin therapy.

Hypothyroid neuropathy is a potential complication of hypothyroidism Hypothyroidism in Animals Hypothyroidism is thyroid hormone deficiency. It is diagnosed by clinical features such as lethargy, weight gain, obesity, haircoat changes, and low serum thyroid hormone concentrations. Management... read more in dogs. Mature dogs, especially large-breed dogs, are predisposed. Several syndromes have been reported, including tetraparesis with proprioceptive deficits and hyporeflexia, vestibular dysfunction, megaesophagus, and laryngeal paralysis Laryngeal Hemiplegia in Horses Laryngeal hemiplegia is a progressive neuropathy of the recurrent laryngeal nerve, leading to atrophy and dysfunction of the cricoarytenoideus dorsalis muscle, an important abductor for the... read more . In some cases, classic signs of hypothyroidism (eg, obesity and dermatopathy) are absent, and neurologic dysfunction is the only sign of illness. Pathologic findings in peripheral nerves consist of demyelination or remyelination and axonal degeneration. The pathophysiology is poorly understood, and, in some affected dogs with motor deficits, a myopathy may also be present. Diagnosis is based on clinical features, laboratory assessment of thyroid function, and response to thyroid supplementation. In some, but not all, cases, signs resolve within several months of starting thyroid replacement therapy.