Sympathetically Maintained Pain Principles of Diagnosis and Therapy

Abstract

The role of the sympathetic nervous system (SNS) has not been defined in acute, chronic or neuropathic pain states. However, there seems to be a significant component in reflex sympathetic dystrophy (RSD) and causalgia. There might be a component in such other neuropathic pain states as postherpetic neuralgia, radiculopathies, certain peripheral neuropathies, and central pain syndromes. The role of the SNS is even less clear in conditions such as phantom pain and pain-dysfunction syndromes (PDS). This is a group of poorly-defined pain syndromes which have many of the clinical characteristics of RSD. They include categories such as Repetitive Strain Injury (RSI), Cumulative Trauma Disorder (CTD), Regional Pain Syndrome or Overuse Syndrome (particularly in musicians). They are characterized by progressive pain (often of a burning nature) throughout the extremity, impairment of function, edema, sensory changes and autonomic dysfunction. As described by Roberts (8) and presented later in Chapter 7, these may represent a group better designated as having sympathetically maintained pain, or they may reflect some abnormality in spinal cord signal processing.