Peripheral Neuropathy

• Frequently asymptomatic, but can lead to the development of additional diabetic complications (e.g., diabetic foot)

• Types include:

  • Distal symmetric polyneuropathy in diabetes

    • A bilateral progressive neuropathy causing sensory loss and/or pain in a stocking glove pattern

    • Most common form of diabetic neuropathy (75%)

  • Mononeuropathy

    • A focal neuropathy that affects a single nerve (e.g., cranial mononeuropathy, mononeuropathy multiplex)

    • Affects < 10% of patients with diabetic peripheral neuropathy

  • Diabetic radioculoplexus neuropathy: most commonly diabetic lumbosacral plexopathy, which manifests as thigh pain and proximal muscle weakness

  • Treatment-induced neuropathy in diabetes (insulin neuritis): a rare small-fiber neuropathy triggered by an improvement in blood glucose levels after chronic hyperglycemia

Many individuals with diabetic peripheral neuropathy are asymptomatic and the condition is often detected only during screening or after complications develop.

• Sensory symptoms

  • Common features

    • Distal symmetrical sensory loss: stocking glove sensory loss pattern with proximal progression

    • Numbness

    • Tingling

    • Dysesthesia (e.g., burning feet syndrome with symptoms that worsen at night)

  • Less common features

    • Allodynia

    • Hyperesthesia

• Motor weakness: e.g., ataxia, balance issues

• Neurological examination may show loss or reduction of:

  • Ankle reflex

  • Vibration sense (using a tuning fork)

  • Sharp/dull discrimination (e.g., pinprick sensation)

  • Light touch (e.g., monofilament test)

  • Proprioception

  • Temperature sensation

Approximately 50% of patients with diabetic peripheral neuropathy are asymptomatic.

• The following neuropathies are more common in patients with diabetes:

  • Compression neuropathies (e.g., carpal tunnel syndrome)

  • Chronic inflammatory demyelinating polyneuropathy

  
  

• Perform diagnostic studies for polyneuropathy to rule out alternative causes.

• Referral to a neurologist for electrophysiological testing is only required for:

  • Atypical presentations

  • Diagnostic uncertainty

Diabetic peripheral neuropathy is a diagnosis of exclusion.

• Manage underlying etiologies.

  • Optimize glycemic control (see “Glycemic targets in diabetes”).

  • Treat dyslipidemia and hypertension, if present.

• Educate patients and caregivers on measures to prevent complications (e.g., preventive measures against diabetic foot).

• Provide pain relief if necessary (see “Analgesia for peripheral neuropathy”).

  • First-line medications include pregabalin, duloxetine, venlafaxine, and amitriptyline.

  • Follow up with patients regularly; adjust medication if pain remains inadequately controlled after 12 weeks of use.

  • For patients with severe or refractory symptoms, consider referral to a pain management specialist.

• Refer to neurology in case of diagnostic uncertainty.

Good glycemic control can prevent the onset and progression of diabetic neuropathy, but it cannot reverse existing nerve damage.

• Diabetic foot ulcers

• Diabetic neuropathic arthropathy (Charcot foot)

• See also “Diabetic foot.”