The causalgia syndrome treated with regional intravenous guanethidine

Two cases of the causalgia syndrome have been presented, one probably related to a mild peripheral neuropathy and the second, more classically, following trauma. The technique of regional infusion of guanethidine has been shown to be efficacious in relieving the pain, if only temporarily, but as it is largely without risk it may be repeated is necessary. It should probably be performed as a routine before consideration of surgical sympathectomy in order to assess whether surgical intervention is likely to be effective. Mechanisms of the causalgia syndrome itself are considered and a rationale for the efficacy of the procedure is suggested.