Diabetic Neuropathy--A Review

Summary and Introduction

Summary

Diabetic neuropathy is the most common neuropathy in industrialized countries, and it is associated with a wide range of clinical manifestations. The vast majority of patients with clinical diabetic neuropathy have a distal symmetrical form of the disorder that progresses following a fiber-length-dependent pattern, with sensory and autonomic manifestations predominating. This pattern of neuropathy is associated with a progressive distal axonopathy. Patients experience pain, trophic changes in the feet, and autonomic disturbances. Occasionally, patients with diabetes can develop focal and multifocal neuropathies that include cranial nerve involvement and limb and truncal neuropathies. This neuropathic pattern tends to occur after 50 years of age, and mostly in patients with long-standing diabetes mellitus. Length-dependent diabetic polyneuropathy does not show any trend towards improvement, and either relentlessly progresses or remains relatively stable over a number of years. Conversely, the focal diabetic neuropathies, which are often associated with inflammatory vasculopathy on nerve biopsies, remain self-limited, sometimes after a relapsing course.

Introduction

Diabetes mellitus is the most common cause of neuropathy worldwide, and is becoming an increasing burden in countries in which the prevalence of obesity is rising. Most of the clinical manifestations of diabetic neuropathy were identified during the second half of the nineteenth century, but our knowledge regarding the pathology of diabetic neuropathies has increased more recently by the unexpected finding of inflammatory lesions in focal diabetic neuropathies. In this review, I will consider the clinicopathological aspects of the various patterns of diabetic neuropathy, starting with length-dependent diabetic polyneuropathy (LDDP), which is by far the most common type of diabetic neuropathy. I will also consider the focal diabetic neuropathies, and discuss the diagnosis of chronic inflammatory demyelinating polyneuropathy, which should not be missed or confused with diabetic neuropathy when it occurs in patients with diabetes.

Given that diabetes affects approximately 246 million people worldwide,^[1] it is estimated that 20-30 million people worldwide are affected by symptomatic diabetic neuropathy. Growing rates of obesity and the associated increase in the prevalence of type 2 diabetes could cause these figures to double by the year 2030. The prevalence of diabetic neuropathy also increases with time and poor glycemic control,^[2,3,4] and severe diabetic polyneuropathy can develop in young adults within a few months after the onset of type 1 diabetes if the diabetes is poorly controlled.^[5]

The author declared no competing interests.

Cite this: Diabetic Neuropathy--A Review - Medscape - Apr 01, 2007.

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