Peripheral sympathetic function as a predictor of complex regional pain syndrome type I (CRPS I) in patients with radial fracture

Complex regional pain syndrome type I (CRPS I) is a frequent complication a fter injuries of the upper limbs. The pathophysiology of this disease remai ns unclear, although disturbances of the sympathetic nervous system have be en detected in several clinical studies, and sympathetic blocks resolve the symptoms in many of the cases. To investigate the meaning of sympathetic d ysfunction at the beginning of the disease. 27 patients with distal radial fracture were examined prospectively during the course of the disease with regard to their clinical symptoms and their peripheral sympathetic nervous function. Sympathetic nervous function was examined by testing the vasocons trictor response to sympathetic stimuli - recorded with laser Doppler fluxm etry - of the fingertips of both hands. Four patients developed CRPS I duri ng the 12-week observation time and two patients presented an incomplete cl inical CRPS I picture ('borderline patients'). The complaints of all patien ts (normal fracture patients, CRPS I patients, borderline patients) were si milar during the first week after trauma with focus on pain, motoric distur bances and autonomic symptoms. After 1 or 2 weeks, a larger clinical differ ence developed between normal fracture patients and CRPS I or 'borderline p atients'. In CRPS I patients and 'borderline patients', the sympathetic vas oconstrictor response was diminished or absent from the first posttraumatic day throughout the observation time, whereas the normal Fracture patients revealed slightly impaired sympathetic nervous function on the first posttr aumatic day and normal results during the rest of the observation time. Wit h regard to the unaffected contralateral hand, CRPS I patients also showed impaired sympathetic nervous function. The results of the present study sug gest that the disturbances in the sympathetic nervous system in CRPS I pati ents are systemic and not limited to the affected limb. Their occurrence be fore the clinical breakout of the disease may serve as a marker that might be useful for early therapy and lead to further understanding of the pathop hysiology of CRPS I. (C) 2000 Elsevier Science B.V. All rights reserved.