There has been a steady decline in the number of deaths of diabetic patients attributable to ketoacidosis and infection, but an alarming rise in the number of the deaths from cardiovascular and renal complications. Long-term complications are becoming more common as more people live longer with diabetes. The long-term complications of diabetes can affect almost every organ system of the body. The general categories of chronic diabetic complications are macrovascular disease, microvascular disease, and neuropathy.

    Diabetic neuropathy refers to a group of diseases that affect all types of nerves, including peripheral (sensorimotor), autonomic, and spinal nerves. The disorders appear to be clinically diverse and depend on the location of the affected nerve cells. The prevalence increases with age of the patient and the duration of the disease and may be as high as 50% in patients who have had diabetes for 25 years.

Elevated blood glucose levels over period of years have been implicated in the etiology of neuropathy. The pathogenesis of neuropathy may be attributed to either a vascular or metabolic mechanism or both, but their relative contributions have yet to be determined. Capillary basement membrane thickening and capillary closure may be present. In addition, there may be demyelinization of the nerves, which is thought to be related to hyperglycemia. Nerve conduction is disrupted when there are aberrations of the myelin sheaths. Control of blood glucose levels to normal or near-normal levels was shown in the DCCT study to decrease the incidence of neuropathy by 60%.

The two most common types of diabetic neuropathy are sensorimotor polyneuropathy and autonomic neuropathy. Cranial mononeuropathies, for example, those affecting the occulomotor nerve, also occur in diabetes, especially among the elderly.

Sensorimotor neuropathy is a diabetic neuropathy also called peripheral neuropathy. It most commonly affects the extremities. It affects both sides of the body symmetrically and may spread in a proximal direction.
Diagnostic test to determine diabetic neuropathy would include physical examination especially foot exam, nerve conduction studies, electromyography (EMG), quantitative skin testing (QST), ultrasound, and nerve or skin biopsy.