Research has led to a better understanding of the risk factors for the development of neuropathy, one of the most common being diabetes, which has been shown to lead to the development of both small and large fiber neuropathy in as many as 60% of all diabetics. However, approximately 25% of cases of neuropathy are classified as “idiopathic,” or of unknown causation. An understanding of the underlying cause can lead to more effective treatment, which means these patients are often left with little hope but symptom management.
Could the answer lie for many of those patients lie in impaired glucose tolerance (IGT) testing? Approximately 10% of adults in the U.S. have “pre-diabetes,” classified as higher than normal blood sugar levels, but not quite high enough to be diagnosed as actual diabetes. Neuropathy associated with IGT has been reported by a number of studies (1, 2), with 1/3 to 1/2 of individuals with idiopathic sensory neuropathy having IGT (3) and IGT occurring in two-thirds of individuals with previously diagnosed idiopathic painful neuropathy (4).
IGT-related neuropathy may represent the earliest stage of diabetic neuropathy. Understanding this link may help control or slow the progression of neuropathy in these patients.
In most cases, the neuropathy associated with IGT is milder than the neuropathy associated with diabetes. While most diabetic neuropathy results in polyneuropathy (neuropathy affecting both small and large nerve fibers), in IGT, small nerve fibers are predominately affected.
If you have symptoms of neuropathy, such as tingling, burning, pain or numbness in your hands or feet, it is important that your physician conduct appropriate testing to understand the possible cause of your symptoms. Neuropathy itself is a symptom, not a disease itself. In the absence of a previous diagnosis of diabetes, oral glucose testing and appropriate blood work may lead to a better understanding, and more effective treatment for your neuropathy symptoms. Epidermal nerve fiber density testing is the sensitive test for small fiber neuropathy.
The sooner your condition is accurately diagnosed, the sooner you may be on your way to a pain-free life. Contact one of our US Neuropathy Center specialists today to get started.
- Sumner CJ, Sheth S, Griffin JW, Cornblath DR, Polydefkis M: The spectrum of neuropathy in diabetes and impaired glucose tolerance.Neurology 60:108–111, 2003
- Pittenger GL, Mehrabyan A, Simmons K, Amandarice, Dublin C, Barlow P, Vinik AI: Small fiber neuropathy is associated with the metabolic syndrome.Metab Syndr Relat Disord 3:113–121, 2005
- Singleton JR, Smith AG, Russell JW, Feldman EL: Microvascular complications of impaired glucose tolerance. Diabetes 52:2867–2873, 2003
- Novella SP, Inzucchi SE, Goldstein JM: The frequency of undiagnosed diabetes and impaired glucose tolerance in patients with idiopathic sensory neuropathy. Muscle Nerve 24:1229–1231, 2001
- Smith AG, Singleton JR: Impaired glucose tolerance and neuropathy. Neurologist 14:23–29, 2008
The advice and information contained in this article is for educational purposes only, and is not intended to replace or counter a physician’s advice or judgment. Please always consult your physician before taking any advice learned here or in any other educational medical material.
@US Neuropathy Centers, 2018