Diabetic Neuropathy: Diagnostic Methods

Screening and diagnostic testing for neuropathy in patients with type 1 or type 2 diabetes is needed in order to prevent complications from diabetic neuropathy. As diabetic neuropathy frequently leads to foot ulcers and amputation— major causes of morbidity and disability in people with diabetes—the American Diabetes Association recommends an annual foot exam for people with diabetes in order to identify those with high-risk foot conditions. Yet, detection and diagnosis of diabetic neuropathy can be complex. The diagnosis of neuropathy is based on both clinical and objective measures. Medical and neurological history, physical and neurological examination (evaluating sensory, motor, reflex, and autonomic function), and measurement of peripheral nerve function by clinical testing have been used and then combined into a series of clinical assessment scores that screen for and quantify the severity of diabetic neuropathy. No fewer than 12 clinical assessment scoring systems are available. This article presents the tools and methods commonly used to screen and diagnose neuropathy in patients with diabetes and discusses issues surrounding their use. (Adv Stud Med. 2004;4(8A):S650-S661) D iabetic peripheral neuropathy (DPN) is one of the common complications of diabetes. The prevalence of DPN has been estimated as 28% in 2 large UK clinic-based studies and 66% in a population-based study in Rochester, Minn. The significant morbidity and mortality associated with DPN has provided impetus for the development of better means to screen, diagnose, and assess the condition. It is also a driving force behind clinical trials for drugs that will prevent DPN or halt its progression when it is already established. By definition, DPN is somatic and/or autonomic neuropathy that is attributed solely to diabetes mellitus. It is a heterogeneous disorder that includes monoand polyneuropathies, plexopathies, and radiculopathies. Neuropathies are classified as symmetrical or asymmetrical (focal or multifocal). The symmetrical form is primarily sensory and autonomic. The asymmetrical form can be sensory, motor, or both, as well as affecting the individual cranial or peripheral nerves. The distal symmetrical form of DPN is known by multiple names including diabetic sensorimotor peripheral neuropathy or distal symmetric diabetic peripheral neuropathy. DPN is often described as a stocking-glove neuropathy, affecting the longest nerves first before progressing proximally. It usually presents with sensory symptoms in the toes or feet, but in some patients whose neuropathy is mainly loss of feeling, it may present with symptoms in the hands. DPN may or may not be accompanied by autonomic neuropathy. Significant motor symptoms usually occur late. Detection of DPN is complicated because the disorder affects a variety of nerve fibers. For diagnosis, it is necessary to assess multiple features of neuropathy. The 1988 consensus statement from the San Antonio Conference on Diabetic Neuropathy recommended, “In REVIEW