Painful neuropathies

Abstract

Purpose of review: To summarize the current understanding of clinical assessment, pathophysiology, and treatment of pain in neuropathies, focusing on selected entities in which the understanding of the mechanisms underlying pain has advanced recently.

Recent findings: Ongoing studies are classifying the symptoms and signs of painful neuropathies, assuming that this approach may indicate particular pathomechanisms leading to more rational treatment. Nerve injury induces a large number of cellular changes, the relevance of which for the occurrence of pain is still under investigation. In models of diabetic neuropathy, an altered distribution of sodium channels, hyperexcitability of neurons, and changes in spinal connectivity seem to underlie the development of pain. The role of inflammatory mediators has been explored in inflammatory and degenerative neuropathies. Second messenger pathways contributing to hyperalgesia in various neuropathies have been identified, opening up new treatment options. A number of newer and older drugs have been studied for their use in painful neuropathies in clinical trials. Epidemiology has shown that, despite the availability of drugs with moderate efficacy in the treatment of neuropathic pain, a large percentage of patients do not gain access to them.

Summary: Advances in the standardization of assessment of patients with painful neuropathies are beginning to have an impact on how clinical studies are designed. Major progress has been made in the understanding of cellular and molecular changes after nerve injury, but their relevance for the pathophysiology of pain in neuropathies has still to be determined.