From the Guidelines
Diabetic neuropathy testing should include a careful history and assessment of either temperature or pinprick sensation and vibration sensation using a 128-Hz tuning fork, as well as annual 10-g monofilament testing to identify feet at risk for ulceration and amputation. According to the most recent guidelines 1, all people with diabetes should be assessed for diabetic peripheral neuropathy starting at diagnosis of type 2 diabetes and 5 years after the diagnosis of type 1 diabetes, and at least annually thereafter. The assessment should include a combination of clinical tests to evaluate small- and large-fiber function, as well as protective sensation.
Some key points to consider when testing for diabetic neuropathy include:
- The use of simple clinical tests, such as pinprick and temperature sensation to assess small-fiber function, and lower-extremity reflexes, vibration perception, and 10-g monofilament to assess large-fiber function and protective sensation 1
- The importance of annual testing to identify feet at risk for ulceration and amputation, as well as to monitor the progression of nerve damage
- The need for a careful history to identify symptoms of autonomic neuropathy, such as orthostatic dizziness, syncope, or dry cracked skin in the extremities
- The use of blood tests to check blood sugar control (HbA1c) as poor glucose control contributes to neuropathy development
Regular testing is crucial for early detection, as early intervention can prevent progression of nerve damage. Patients with diabetes should have their feet examined at least annually, or more frequently if they already have neuropathy symptoms like numbness, tingling, or pain in their extremities. Electrophysiological testing or referral to a neurologist is rarely needed, except in situations where the clinical features are atypical or the diagnosis is unclear 1.
From the Research
Diagnosis of Diabetic Neuropathy
- Diabetic neuropathy can be diagnosed based on clinical findings, including type of pain, time of occurrence, and abnormal sensations 2
- The 10 g monofilament pressure test and standard electrophysiological procedures may be normal in patients with painful diabetic peripheral neuropathy (PDN) due to small-fibre injury 2
- The DN4 questionnaire is an easy-to-use validated diagnostic tool for diagnosing PDN 2
Symptoms of Diabetic Neuropathy
- Patients with diabetic neuropathy may present with numbness, tingling, pain, and loss of sensation in the extremities 3
- Distal symmetric polyneuropathy is the most common form of diabetic neuropathy 4
- Diabetic neuropathy can also cause motor deficits, silent cardiac ischemia, orthostatic hypotension, vasomotor instability, hyperhidrosis, gastroparesis, bladder dysfunction, and sexual dysfunction 4
Testing for Diabetic Neuropathy
- There is no specific test mentioned in the studies for diagnosing diabetic neuropathy, but rather a combination of clinical findings and diagnostic tools such as the DN4 questionnaire 2
- The diagnosis of diabetic neuropathy is based on a systematic questioning of patients concerning suggestive symptoms, as they are not usually volunteers 2
Prevention of Diabetic Neuropathy
- Strict glycemic control and good daily foot care are key to preventing complications of diabetic neuropathy 4
- Intensive glycemic control with insulin in patients with type 1 diabetes may be associated with lower odds of distal symmetric polyneuropathy compared to patients who receive conventional insulin therapy 5