Neuropathic pain, back to the patient

Abstract

Pain can be classified in several ways. The International Association for the Study of Pain (IASP) recommends describing pain according to five categories or axes, namely its anatomical location (neck, lower back, etc.), the body system involved (gastrointestinal, nervous, etc.), temporal characteristics (intermittent, constant, etc.), intensity and time since onset, and etiology (cause). The idea to discriminate between ‘nociceptive’ pain and ‘neuropathic’ pain only came into common clinical practice in the last decade. Since then, probably due to the therapeutic consequences of this classification, the proposal has become increasingly appreciated as a meaningful way to define pain. In nociceptive or somatic pain, the initial stimulus of the peripheral nociceptor is produced chemically as a result of (potential) tissue damage. In contrast, neuropathic pain results from complex changes in the physiology of the nerve involved; this implies an affliction anywhere along the neuraxis from cortical neurons down to neurons in the anterior horn cell or in ganglia of the peripheral nervous system. The causes of neuropathic pain include structural damage by disease, trauma, metabolic disturbance, and infection.