Reflex sympathetic dystrophy associated with amyotrophic lateral sclerosis

Reflex sympathetic dystrophy (RSD) is a syndrome characterised by severe di stal pain and vasomotor changes. It is believed to be caused by sympathetic nervous system overactivity. Trauma is the most frequent precipitant event . An association with amyotrophic lateral sclerosis (ALS) has been reported only once. We report three patients with ALS in whom the occurrence of RSD , in one of them at a very early clinical stage, seemed to have precipitate d a more rapid clinical evolution. New sprouting re-innervating fibres have abnormal ion channels which might increase the risk of RSD. On the other h and, motor changes have been described in RSD, as well as motor strength im provement after RSD treatment. The complex relation of ALS with RSD is disc ussed. In all ALS patients pain followed by further lass of function should prompt a search for RSD. (C) 1999 Elsevier Science B.V. All rights reserve d.