Clinical Diagnosis of Diabetic Peripheral Neuropathy

Diabetic distal symmetric polyneuropathy (diabetic DSP) has variable clinical presentation that can complicate the diagnostic process. It is primarily identified by asymptomatic annual screening or from neuropathic symptoms. In this chapter, we present key considerations for findings on screening or clinical evaluation. First, identification of risk factors for diabetic DSP establishes a general pre-assessment probability. Second, identification of the other component causes (foot deformity, vascular impairment) of foot complications along with identifying the impaired protective sensation that is part of diabetic DSP is essential for preventing foot outcomes. Third, the clinician must recognize that there is heterogeneity in manifestations, involving small and large nerve fiber types. As in any process of diagnosis, a clinical evaluation considers each symptom or sign’s contribution to incrementally revising the clinician’s estimates of disease probability and it reduces clinical uncertainty. Simple screening methods are valid, as are clinical scales, adopted into research cohorts and trials, that can be implemented into practice. Once a chronically-progressive distal symmetric pattern of polyneuropathy is confidently identified, alternate causes can generally be accomplished by simple clinical considerations and simple laboratory testing. While uncommon, a typical features such as asymmetry, nonlength dependence, acute or subacute rather than chronic onset and progression, and motor predominance call for specialized testing and clinical expertise from a neurologist. Depending on the number and severity of deformity, vascular insufficiency, and diabetic DSP’s impairment in protective sensation, interventions are initiated including self-foot care education and professionally-fitted therapeutic footwear to referral for wound management and surgical consultation.