Neuropathic pain syndromes are chronic pain disorders caused by lesion or disease of the parts of the nervous system that normally signal painA disease- and anatomy-based system is often insufficient to classify neuropathic pain conditions, and analysis on the basis of underlying mechanisms provides an alternative approachMolecular mechanisms that underlie the sensitization of primary afferent nociceptors include upregulation of voltage-gated sodium channels and various receptor proteins, and the release of growth factors from degenerating nerve fibersAs a consequence of peripheral nociceptor hyperactivity, dramatic secondary changes occur in the spinal cord dorsal horn, and there is also evidence of sensitization of neurons in the brainA single symptom may be generated by several different mechanisms, so a specific symptom profile might be required to predict the underlying mechanismBy combining a systematic clinical examination and a precise phenotypic characterization with a selection of drugs that act on particular mechanisms, it should be possible to design optimal treatments for individual patients
Traditionally, clinicians have been taught to examine and classify patients on the basis of lesion topography and underlying pathology, an approach that has proved invaluable for understanding the pathophysiology of many diseases, including bacterial meningitis and osteoarthritis. In most of these disorders, pain is a symptom that rapidly disappears after the relevant therapy has been given, but in other conditions, such as diabetes mellitus, the underlying disease cannot be cured, and pain becomes the primary concern rather than a symptom.
