MedifocusHealth

• Only a subset of patients respond to a treatment to reduce pain called a sympathetic block which interrupts the activity of the sympathetic nervous system indicating that not all RSD pain is sympathetically mediated
• Dystrophy (degeneration of muscle or tissue) is present only in a subset of RSD patients (approximately 10%)

In response to these inconsistencies, the International Association for the Study of Pain (IASP) adopted the term complex regional pain syndrome (CRPS) in 1994 to describe a debilitating pain syndrome that develops after a relatively minor injury to an extremity (arm or leg) but lasts longer than the actual injury and is more severe than would otherwise be expected from such an injury. There are two types of CRPS:

• CRPS Type I- also known as reflex sympathetic dystrophy where the pain is not associated with an identifiable nerve injury
• CRPS Type II - also known as causalgia where the pain can be traced to a nerve injury

Despite extensive research over the past several decades, researchers still do not understand clearly the underlying pathological mechanisms involved in the initiation and progression of RSD including:

• Why RSD develops in some people and not others.
• Why RSD goes into remission for some people and not others.
• Why some people experience recurrence of RSD.
• What are the most effective treatments for RSD?
• How to prevent RSD from occurring.