Multifocal or generalized tonic dystonia of complex regional pain syndrome: a distinct clinical entity associated with HLA-DR13.

We report on 26 patients with a distinct phenotype of complex regional pain syndrome that progressed toward a multifocal or generalized tonic dystonia. The dystonia initiated distally, involved mainly flexor muscles, and was associated with sensory and autonomic symptoms. Dryness of the eyes or mouth and bladder and bowel disturbances were frequently reported. There was no increase in the familial prevalence of autoimmune-mediated diseases. Compared with controls, a significant elevation of HLA-DR13 was found in the patients. Thus, HLA-DR13 may be a factor indicating susceptibility to this distinct phenotype of complex regional pain syndrome.