Diabetic Neuropathy
Nerve damage from diabetes causing numbness, tingling, and severe pain, typically starting in the feet.
Emergency Management: Deep space foot infection with systemic signs of sepsis requiring emergent surgical decompression and IV antibiotics.
Diabetic neuropathy is a heterogeneous group of nerve disorders caused by diabetes, with distal symmetric polyneuropathy (DSPN) being the most common form. It is characterized by progressive loss of nerve fiber function, leading to sensory loss, pain, and autonomic dysfunction, primarily affecting the lower extremities in a stocking-glove distribution.
Detailed Overview
Neuropathy is the most common microvascular complication of diabetes. It insidiously causes loss of protective sensation, leading to unrecognized microtrauma, foot ulcerations, and ultimately lower extremity amputations. Painful diabetic neuropathy affects up to 25% of patients, severely impacting quality of life. Strict glycemic control is the only proven method to prevent its progression.
Epidemiology & Demographics
Affects approximately 50% of adults with diabetes over their lifetime. More prevalent in Type 2 than Type 1 diabetes at the time of diagnosis.
Etiological Mechanism
Chronic hyperglycemia leading to metabolic and microvascular alterations that damage peripheral nerves and their supplying vasa nervorum.
Primary Causes
Type 1 and Type 2 Diabetes Mellitus.
Hyperglycemia saturates the hexosamine and polyol pathways, leading to accumulation of sorbitol and fructose in nerves, which causes osmotic stress and decreases cellular myo-inositol. Advanced glycation end products (AGEs) cross-link structural proteins and induce oxidative stress. Microvascular disease of the vasa nervorum causes nerve ischemia. Ultimately, this results in axonal degeneration, demyelination, and impaired nerve conduction, particularly in the longest nerve fibers (distal axonopathy).
Diagnostic Criteria & Guidelines
Clinical diagnosis based on the presence of symptoms and/or signs of peripheral nerve dysfunction in people with diabetes after the exclusion of other causes. Confirmed by abnormal 10-g monofilament test, pinprick, or vibration testing.
Strict glycemic control (target HbA1c < 7%). For neuropathic pain: Pregabalin 50-75 mg PO TID (max 600 mg/day), Gabapentin 300 mg PO TID titrated to 3600 mg/day, or Duloxetine 60 mg PO daily.
Second-Line & Adjunctive Therapy
Tricyclic antidepressants: Amitriptyline 10-25 mg PO QHS (use with caution in elderly). Topicals: Capsaicin 0.075% cream QID or Lidocaine 5% patches.
Surgical & Procedural Management
Debridement of necrotic foot ulcers. Revascularization (bypass or endovascular) if concomitant peripheral arterial disease exists. Amputation (toe, transmetatarsal, BKA, AKA) for severe gangrene or life-threatening infection.
Patient Counseling & Advice
Inform patients that pain medications will reduce pain but not restore lost sensation. Emphasize that foot care is a daily critical necessity to prevent amputation.
Follow-Up & Monitoring Schedule
Comprehensive foot exam annually for all diabetics; every 3-6 months for those with established neuropathy. Assess monofilament and pulses.
Preventive Strategies
Intensive glycemic control in type 1 diabetes prevents DSPN by up to 78%; in type 2 diabetes, modest prevention requires multifactorial risk reduction (glucose, lipids, BP).
Nerve damage is largely irreversible. The goal is symptom management and prevention of complications. 5-year mortality after a major lower extremity amputation is >50%.