Make the Diagnosis: Diabetic Peripheral Neuropathy
Prior Probability of Large-Fiber Peripheral Neuropathy in Diabetes
The highest quality studies show a prevalence of 39%-77% of large-fiber peripheral neuropathy in patients with Type 2 diabetes.1, 2
Population in Whom Large-Fiber Peripheral Neuropathy Should Be Suspected
Because of its high prevalence and because some patients have an insensate foot without symptoms, annual screening for large-fiber peripheral neuropathy among patients with diabetes is recommended.
Physical and Neurological Examination and Screening
Examination should include physical assessment of the legs and feet and neurological examination. Symptoms that should prompt an examination include tingling, numbness, or a sensation of heaviness in the hands or legs; burning, stabbing pain, or cramps in the arms or legs; a sensation that the walking surface feels unusual or that the patient has trouble perceiving uneven surfaces; experiencing trauma to the skin of the feet without pain; or weakness in the legs while climbing stairs. The clinician must recognize that patients with diabetes can have neuropathy for reasons unrelated to their diabetes, so the symptoms of neuropathy require a review of conditions that can cause peripheral neuropathy.
Useful findings for detecting diabetic large-fiber neuropathy are shown in Table 77-1. While a positive result on the Symptoms of Neuropathy screening questionnaire (Box 77-1) identifies patients more likely to have large-fiber neuropathy (LR, 4.0; 95% CI, 2.9-5.6) and a negative result identifies patients less likely to have large-fiber neuropathy (LR, 0.19; 95% CI, 0.10-0.38), the physical examination findings perform better.
Table 77-1Useful Findings for Detecting Diabetic Large-Fiber Neuropathy |Favorite Table|Download (.pdf) Table 77-1 Useful Findings for Detecting Diabetic Large-Fiber Neuropathy
| ||Abnormal ||LR+ (95% CI) ||LR- (95% CI) |
| || ||Screening Questionnaire |
|Neuropathy screening questionnaire3 (see Box 77-1) ||Score >4 ||4.0 (2.9-5.6) ||0.19 (0.10-0.38) |
| || ||Clinical Examination |
|Vibration testing, on-off technique (tested at 2 sites/foot)4,a ||Score ≥5 out of 8 ||35 (5.0-252) |
| ||2-4 of 8 ||3.9 (2.0-7.5) |
|≤1 of 8 ||0.51 (0.45-0.57) |
|Semmes-Weinstein monofilament sensory testingb ||Studies use varying definitions of abnormal4, 5 ||Range 11-16 ||0.54 (0.46-0.64) |
Box 77-1Questionnaire on Symptoms of Neuropathy (Italian Society of Diabetology)3,a |Favorite Table|Download (.pdf) Box 77-1 Questionnaire on Symptoms of Neuropathy (Italian Society of Diabetology)3,a
|1. Have you ever felt tingling, numbness, or heaviness in your hands or legs? |
|2. Have you ever felt burning, stabbing pain, pains, or cramps in your legs or arms? |