The role of peripheral nerve injections in the diagnosis and treatment of CRPS

It was Claude Bernard, a French physician and physiologist, who first correlated pain with sympathetic nervous system in the mid1800’s [1]. The first detailed descriptions of sympathetically-mediated pain came from one of his students, Silas Weir-Mitchell, in his book “Gunshot Wounds and other Injuries of Nerves”, published in 1864 [2]. During the American Civil War, Mitchell noted that some soldiers developed a particularly painful state after bullet injuries. In his reports, he described soldiers who experienced burning pain that never affected the trunk, rarely affected the thighs and arms, but often involved the legs and forearms, and mainly involved the hands and feet. The patients described burning pain, which became intensely hyperalgesic. At some point, they avoided even contact with the air, which now we know as allodynia. As time went by, the patient’s face showed evidence of suffering, they developed sleep disturbances, and finally, they became hysterical. A few years later, Mitchell coined the term “causalgia” (from Greek kausos fever + algia pain) to describe this condition [3].