Diabetic Peripheral Neuropathy Diagnosis and Management

Diagnostic Criteria

The American Diabetes Association recommends assessing diabetic peripheral neuropathy (DPN) 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, 2
Up to 50% of DPN cases are asymptomatic but still increase risk for foot ulceration and amputation, highlighting the importance of systematic screening 2, 3
DPN is a diagnosis of exclusion, and other causes of neuropathy, such as toxins, neurotoxic medications, vitamin B12 deficiency, hypothyroidism, renal disease, malignancies, infections, chronic inflammatory demyelinating neuropathy, and inherited neuropathies, must be ruled out 2, 4

Small-fiber function assessment should include pinprick and temperature sensation tests 1, 2
Large-fiber function assessment should include vibration perception using a 128-Hz tuning fork and 10-g monofilament testing 1, 4
Protective sensation assessment should include 10-g monofilament testing to identify feet at risk for ulceration 1, 2

The American Diabetes Association recommends optimizing glucose control to prevent or delay neuropathy development in type 1 diabetes and slow progression in type 2 diabetes, with a target HbA1c of 6-7% 4
First-line treatments for painful DPN include pregabalin and duloxetine, while alternative options include gabapentin, tricyclic antidepressants, venlafaxine, and carbamazepine 5

Regular foot examinations are critical to prevent complications, and all patients with DPN should have annual 10-g monofilament testing to identify feet at risk for ulceration 1, 4
Patient education about foot care is essential to prevent ulceration and amputation, although the specific recommendations are not clearly outlined in the provided citations
The American Diabetes Association recommends screening for autonomic neuropathy in patients with evidence of DPN, including questions about orthostatic dizziness, syncope, and dry/cracked skin, as well as signs such as orthostatic hypotension, resting tachycardia, and peripheral skin dryness/cracking 1, 4

Burning feet syndrome in diabetics is typically caused by small fiber neuropathy, manifesting as pain and dysesthesia (unpleasant sensations of burning and tingling) 6

The American Diabetes Association recommends pregabalin, duloxetine, or gabapentin as the first-line pharmacological treatments for burning feet syndrome in diabetic patients, which is a manifestation of diabetic peripheral neuropathy (DPN) 6, 7
Duloxetine improves neuropathy-related quality of life 6
Duloxetine may cause a small increase in A1C in longer-term studies 6
Gabapentin is recommended at doses of 300-1,200 mg three times daily 7
One high-quality study and many small studies support the efficacy of gabapentin in treating DPN pain 7

Tricyclic antidepressants (e.g., amitriptyline) are effective for neuropathic pain but require monitoring for anticholinergic side effects, especially in patients ≥65 years 7, 8
Sodium channel blockers (lamotrigine, lacosamide, carbamazepine, oxcarbazepine, valproic acid) are supported by five medium-quality studies 7
Capsaicin (8% patch or 0.075% cream) has received FDA approval for DPN pain treatment 7, 8
Tapentadol and tramadol should generally be avoided due to their opioid properties and risk of addiction 7

Optimize glucose control to slow the progression of neuropathy in patients with type 2 diabetes 6, 9
Regular foot examinations with 10-g monofilament testing to identify feet at risk for ulceration 9

Adverse events from medications may be more severe in older patients but can be attenuated with lower starting doses and slower titration 6, 7
Opioids should generally be avoided for chronic neuropathic pain due to risk of addiction 7
Conventional lipid-lowering pharmacotherapy (statins or fenofibrates) does not appear effective in treating or preventing DPN development 7

Diabetic peripheral neuropathy (DPN) classically causes distal symmetric sensory symptoms starting in the feet, not isolated calf muscle pain, according to the American Diabetes Association 10
The most common early symptoms of DPN involve small fiber dysfunction, including burning pain, tingling, and dysesthesia (unpleasant sensations) starting in the toes and feet, as recommended by the American Diabetes Association 10
Large fiber dysfunction in DPN involves numbness, loss of vibration sense, and loss of protective sensation, as noted by the American Diabetes Association 10

Peripheral arterial disease (PAD) can cause claudication pain in the calves and must be distinguished from neuropathy, as stated by the American Heart Association 11
Musculoskeletal causes, such as direct muscle or joint pathology, can also cause calf pain in diabetic patients, according to the American Diabetes Association 10

If calf pain is confirmed to be neuropathic in origin with appropriate distal-to-proximal progression, first-line treatment includes pregabalin or duloxetine, as recommended by the American Diabetes Association 11