Concept and limits of the reflex sympathetic dystrophy.

Reflex sympathetic dystrophy (RSD) is a clinical syndrome defined in the English literature by pain, dystrophic tissue changes and local disturbance of autonomic function in a limb or part of a limb. Algodystrophy is the common name used for the condition in the French literature, in which the concept also includes the "transient regional osteoporosis" and the "regional migratory osteolysis". We want to discuss three points: 1) Are the RSD, transient regional osteoporosis and migratory osteolysis different diseases or different manifestations of a single condition? We believe that an objective differentiation is not possible between them. Our report about 28 cases of polytopic RSD shows the frequent association in the same patient of these manifestations and we believe that this represents the broad spectrum of a single disease. 2) Is the accepted classic pathophysiologic mechanism of RSD accurate? The conception of a disturbance of autonomic function is not easily linked with its association with conditions such as diabetes, hyperthyroidism, hyperlipidaemia and others. Even more difficult to explain is the association with malignancy and osteomalacia. The deposit of immunoglobulins that we have demonstrated in two cases in the palmar fascia of RSD associated with malignancy suggests a possible immunological mechanism. 3) What are the limits of RSD? The association between RSD and aseptic necrosis of the hip has been reported. Are they two different conditions or is the aseptic necrosis only a more developed form of RSD? Finally, we report the first single case of Munchausen syndrome mimicking a RSD of the hand with the same clinical, radiological and scintigraphic appearance.