Diabetic Peripheral Neuropathy Diagnosis and Treatment
Diabetic peripheral neuropathy (DPN) should be assessed in all patients with type 2 diabetes at diagnosis and in type 1 diabetes 5 years after diagnosis, with annual screening thereafter, using standardized clinical tests of small and large fiber function. 1
Diagnostic Criteria
Clinical Assessment
- All patients with diabetes require systematic screening for DPN using both medical history and simple clinical tests 1
- Up to 50% of DPN cases are asymptomatic but still increase risk for foot ulceration and amputation 1
- DPN is a diagnosis of exclusion - other causes of neuropathy must be ruled out 1, 2
Required Clinical Tests
- Small-fiber function assessment: pinprick and temperature sensation 1
- Large-fiber function assessment: vibration perception using 128-Hz tuning fork and 10-g monofilament testing 1
- Protective sensation assessment: 10-g monofilament testing (critical for identifying feet at risk for ulceration) 1
Common Symptoms and Signs
- Early symptoms typically involve small fibers: pain and dysesthesias (burning and tingling sensations) 1
- Large fiber involvement causes numbness and loss of protective sensation (LOPS) 1
- Symptoms follow a "glove and stocking" distribution, starting distally and spreading proximally 3
Differential Diagnosis
- Rule out other causes of neuropathy before confirming DPN diagnosis 1:
- Toxins (alcohol)
- Neurotoxic medications (chemotherapy)
- Vitamin B12 deficiency
- Hypothyroidism
- Renal disease
- Malignancies (multiple myeloma, bronchogenic carcinoma)
- Infections (HIV)
- Chronic inflammatory demyelinating neuropathy
- Inherited neuropathies
- Vasculitis 1
When to Consider Additional Testing
- Electrophysiological testing or neurologist referral is rarely needed except when clinical features are atypical or diagnosis is unclear 1
Treatment Options
Glycemic Control
- Optimize glucose control to prevent/delay neuropathy development in type 1 diabetes and slow progression in type 2 diabetes 1, 2
- Target HbA1c of 6-7% is recommended for neuropathy management 2
Pharmacological Management for Painful DPN
- First-line treatments (FDA-approved):
- Alternative options:
Important Treatment Considerations
- All pharmacological treatments except glycemic control are symptomatic only and do not affect natural progression of nerve fiber loss 2
- Medication selection should be based on comorbidities, potential side effects, and drug interactions 2, 6
- Regular monitoring of treatment response is essential as benefits may be modest and side effects common 6
- Opioids should generally be avoided for DPN pain management 6
Non-pharmacological Approaches
- Address cardiovascular risk factors (hypertension, hyperlipidemia) 2
- Exercise and physical activity may provide benefits 2, 6
- Consider transcutaneous electrical nerve stimulation (TENS) for modest pain relief 6
Autonomic Neuropathy Assessment
- Screen for autonomic neuropathy in patients with evidence of DPN 1
- Assessment should include questions about orthostatic dizziness, syncope, dry/cracked skin 1
- Signs include orthostatic hypotension, resting tachycardia, peripheral skin dryness/cracking 1
Prevention and Monitoring
- Regular foot examinations are critical to prevent complications 1, 7
- All patients with DPN should have annual 10-g monofilament testing to identify feet at risk for ulceration 1
- Patient education about foot care is essential to prevent ulceration and amputation 7