Effects of Diabetes on the peripheral nervous system
Damage to the peripheral nervous system accounts for the main neurologic manifestations of diabetes.
Approximately 50% of diabetic patients will develop a neuropathy. Initially, a symmetric distal stocking-and-glove sensory neuropathy involving small, unmyelinated or thinly myelinated fibers appears and is often associated with painful, burning paresthesias.
In more severe cases, larger proprioceptive fibers are also affected, leading to Charcot joints.
The cumulative exposure to hyperglycemia is thought to be the most important risk factor. The typical diabetic neuropathy can be slowed or sometimes even improved with better glycemic control.
Autonomic nerve damage causes atrophic skin changes, impotence, orthostatic hypotension, arrhythmias, gastroparesis, and sphincter incontinence.
Motor fibers may also be damaged, leading to symmetric distal weakness, especially of the lower extremities.
Focal destruction of nerves may cause cranial nerve palsies, diabetic amyotrophy, and thoracoabdominal neuropathy.
