Assessment of peripheral sympathetic nervous function for diagnosing earlypost-traumatic complex regional pain syndrome type I

Clinical diagnosis of complex regional pain syndrome type I (CRPS I) in pos t-traumatic patients is often delayed since the clinical appearance of this disease resembles normal post-traumatic states to a certain extent (pain, edema, loss of function). The purpose of this study was to assess the incid ence of specific clinical features in CRPS I patients and normal post-traum atic patients and to evaluate the diagnostic value of a bedside test that m easures the sympathetic nervous function. Fifty patients with post-traumati c CRPS I of the upper limb and 50 patients 8 weeks after distal radius frac ture with an undisturbed course of disease were subjected to a detailed cli nical examination. Pain was assessed using the VAS (visual analog scale), s kin temperature measured with an infrared camera and grip-strength with a p neumatic manometer. In CRPS I patients, motor disturbances defined as an im paired active range of motion of the hand, were most frequent (96%, fractur e patients: 40%), followed by edema (88%, fracture patients: 80%) and spont aneous pain (VAS 4.0 +/- 2.3, fracture patients: VAS 1.3 +/- 0.6). Systemat ic temperature differences (>1 degrees C) between the affected and unaffect ed limbs were seen in only 42% of CRPS I patients and in 34% of the fractur e patients. Further sensory, sudomotor or trophic changes of the hands were rare. As expected, there were significant differences in the quantity of e dema, motor disturbances and sensory disturbances between CRPS I patients a nd normal fracture patients. However, normal fracture patients still suffer ed from several of the evaluated symptoms 8 weeks after trauma, which makes an early clinical diagnosis of the complication more difficult. Using a ne wly developed bedside test, the peripheral sympathetic nervous function was assessed in both groups of patients and in 50 age-matched healthy controls . The decrease in skin blood flow following sympathetic provocation maneuve rs, detected by laser Doppler flowmetry, was quantified as sympathetic reac tivity. In the affected hands of CRPS I patients, as well as in the contral ateral hands, the sympathetic reactivity was obliterated or diminished in c ontrast to the age-matched controls and normal fracture patients. A multiva riate analysis did not reveal any correlation between sympathetic function and the severity of any clinical symptom. Sympathetic reactivity seems to b e an independent variable in CRPS I and the test presented may facilitate t he difficult clinical diagnosis of this disease. (C) 1999 International Ass ociation for the Study of Pain. Published by Elsevier Science B.V.