Diabetic Polyneuropathy

Description

Peripheral nerve dysfunction seen in diabetes; several patterns described:

• Symmetric polyneuropathy
  • Distal sensory or sensorimotor
• Mononeuropathy, radiculopathy, and polyradiculopathy
  • Cranial neuropathy
  • Focal limb or truncal neuropathy
  • Radiculoplexus neuropathy (diabetic amyotrophy)
• Acute painful small fiber neuropathy
• Autonomic neuropathies
• Chronic inflammatory demyelinating polyneuropathy (CIDP)

Epidemiology

Prevalence

• Generalized polyneuropathy
  • 10–30% at diabetes diagnosis
  • In diabetes, 50% at 10 years
  • Prevalence is higher in type 2 diabetes than type 1 diabetes.
• Autonomic neuropathy: 16.7% in a United Kingdom study

Etiology and Pathophysiology

• Metabolic derangement due to hyperglycemia and dyslipidemia
  • Aldose reductase converts excess glucose to sorbitol, which causes nerve damage.
  • Nonenzymatic glycation of neural proteins and lipids forms damaging advanced glycosylation end products.
  • Protein kinase C activation causes vascular endothelial changes.
  • Oxidative stress from excessive production of reactive oxygen species
  • Mitochondrial dysfunction and impaired mitochondrial trafficking within the neurons
• Vasculopathy causing nerve ischemia: predominant factor in mononeuropathies

Risk Factors

• Poor glycemic control
• Duration of diabetes
• Hypertension
• Dyslipidemia
• Obesity
• Tobacco and alcohol consumption

General Prevention

• Maintenance of normal blood sugar
• Exercise and appropriate diet