The reflex sympathetic dystrophy syndrome: A review with special reference to chronic pain and motor impairments

Reflex sympathetic dystrophy (RSD) is manifested by pain, vasomotor and trophic disregulation, and by various motor impairments. Its course shows a large variability, but an acute stage can roughly be discriminated from a chronic stage. The aim of this paper is to review the literature on RSD with regard to diagnosis and pathophysiology, in particular referring to chronic pain and motor impairments. It will be demonstrated that complementary investigations are helpful in making a definite diagnosis. RSD appears to be multicausal. In the acute stage, overproduction of toxic free radicals, sympathetic nervous system disregulation and neurogenic inflammatory reactions predominate. In the more chronic stage, a shift from peripheral to central mechanisms seems to take place. This centralization is probably an essential factor in the development and maintenance of both pain and RSD-associated motor impairments such as tremor, dystonia, increased muscle tone, muscle spasms and weakness. It is concluded that insight into the mechanisms underlying chronic pain and motor impairments in RSD has clear clinical implications, both for preventing disabilities and for developing rehabilitation strategies during the more chronic stages of RSD.