Diabetic neuropathies

Abstract

Purpose of review: This article provides an overview for understanding the diagnosis, pathogenesis, and management of diabetic neuropathy.

Recent findings: New information about the pathogenesis of diabetic neuropathy continues to emerge, which will lead to identifying new drug targets. It is clear that the natural history of diabetic neuropathy is changing and the rate of progression is slowing. This is likely because of a combination of earlier diagnosis, improved glycemic management, and improved control of related complications such as hyperlipidemia and hypertension. Early diagnosis is critical, and small fiber neuropathy or subclinical diabetic neuropathy may be reversed or significantly improved with appropriate intervention. The American Academy of Neurology recently published guidelines for the treatment of painful diabetic neuropathy.

Summary: Diabetic neuropathy is common and can present with varied clinical presentations discussed in this article. Although treatment currently focuses on pain management, attention should be paid to potential risk factors for neuropathy. For example, glycemic control, hyperlipidemia, and hypertension should be managed with diet, exercise, and medications. Class I or II clinical studies indicate that pregabalin, duloxetine, amitriptyline, gabapentin, and opioids are effective in the management of diabetic neuropathic pain.

Figure 3-1

Quantitative Sudomotor Axon Reflex Test (QSART) measures sweat output in the forearm and lower extremity. Compared with the nondiabetic control, there is a decrease in sweating in the distal leg and foot. In contrast, sweat generation in the forearm is normal and marginally decreased in the proximal leg.

Figure 3-2

A decrease in heart rate variability (beat-to-beat variation) with deep breathing is present in diabetic autonomic neuropathy.

Figure 3-3

Partial conduction block, with proximal stimulation, in a patient with diabetes mellitus. The primary cause of the neuropathy in this patient is multifocal neuropathy with conduction block. NCS = nerve conduction study; L = left; APB = abductor pollicis brevis.