Peripherally-triggered CRPS and dystonia.

It is increasingly recognised that the Complex Regional Pain Syndrome (CRPS) may be accompanied by several movement disorders, and as a consequence these are now included amongst the proposed research criteria for diagnosis of CRPS (Bruehl et al., 1999). Some of these movement disorders, including weakness, stiffness, clumsiness, and motor neglect, give rise to impaired movements. Others give rise to various involuntary movements, including tremor, myoclonus, spasms, jerks, and notably dystonia – ‘a movement disorder that causes sustained muscle contractions, repetitive twisting movements, and abnormal postures of the trunk, neck, face, or arms and legs’ (Tarsy and Simon, 2006). CRPS is frequently triggered by peripheral trauma, and, as discussed below, appears to be associated with dystonia surprisingly often. In contrast, dystonia is only rarely associated with CRPS, and whether dystonia is triggered by trauma remains controversial (see Jankovic, 2001; Weiner, 2001). In the light of these similarities and differences, are peripherally-triggered CRPS and dystonia sometimes linked, as has been postulated in the past (Schott, 1986); and if so, how?