The term metabolic neuropathy refers to nerve disorders associated with systemic diseases of metabolic origin. 

These diseases include diabetes mellitus, hypoglycemia, uremia, hypothyroidism, hepatic failure, polycythemia, amyloidosis, acromegaly, porphyria, disorders of lipid/glycolipid metabolism, nutritional/vitamin deficiencies, and mitochondrial disorders, among others. 

The common factor of these diseases is damage to the nerves by alteration of the structure or function of the myelin sheath and axons due to metabolic pathway dysregulation.

Diabetes is the most common cause of metabolic neuropathy, followed by uremia. 

Some of these disorders  also affect muscles due to the fact that the conditions damage motor nerves which send incorrect signals to the muscles.