Pain of unknown cause that results when special nerve endings, called nociceptors, are stimulated. Neuropathic pain is possible whenever nerves are damaged by trauma; by diseases such as diabetes, herpes zoster, and late-stage cancer; or by chemical injury (e.g., toxic doses of drugs). The most dramatic and mysterious example of neuropathic pain is called phantom limb syndrome. This occurs when an arm or a leg has been removed because of illness or injury but the brain still gets pain messages from the nerves that originally carried impulses from the missing limb. These nerves now seem to misfire and cause troubling pain.
Pain that originates in peripheral nerves or the central nervous system rather than in other damaged organs or tissues. A hallmark of neuropathic pain is its localization to specific dermatomes or nerve distributions. Some examples of neuropathic pain are the pain of shingles (herpes zoster), diabetic neuropathy, radiculopathy, and phantom limb pain.
Pain that arises as a consequence of a lesion or disease of the nervous system. It is always abnormal and is always due to malfunctioning of the nervous system, particularly of the somatosensory system (the part of the nervous system that deals with sensory signals from the body). If the lesion is restricted to peripheral nerves, the pain is called peripheral neuropathic pain. If the lesion is located in the central nervous system, it is called central neuropathic pain.