Further vascular, bone and autonomic investigations in algodystrophy.

Direct clinical observation is the most common means of diagnosing algodystrophy. Further investigations may be helpful to rule out other pathological conditions, such as occult or stress fractures or avascular osteonecrosis and to obtain a better understanding of algodystrophy. Transient vascular hyperpermeability in the affected part is well demonstrated by the clinical findings, the MRI signs, and the three-bone scan features. 99m Technectium EHDP bone scan provides an evaluation of the vascular abnormalities and of the osteoblastic activity. Dermal microcirculation and its reactions to sympathetic stimuli are investigated by laser doppler fluximetry and videophotometric capillaroscopy. Perhaps the sweat test does unveil what might be specific about algodystrophy. The amount of bone loss in algodystrophy in a few weeks or months is what might be expected over 10 years during the natural history of uncomplicated osteoporosis. An initial fracture is undoubtedly an initiating event in the appearance of algodystrophy, but patients suffering from algodystrophy may still have significant osteoporosis for a long period and hence be at risk for fracture. Densitometry could be an aid to the diagnosis and probably to monitoring treatment as well. The local colonization of fibroblasts following the transient stage of hyperpermeability must be kept in mind to explain the results of joint, bone, muscles or neurological investigations in late algodystrophy.