[Diagnosis of sympathetic reflex dystrophy. Comparison of ischemia test and modified guanethidine blockade]

Recently, the ischemia-test (IT) had been suggested to be part of the diagnostic procedure for reflex sympathetic dystrophy (RSD). The present study investigated, for the first time whether pain suppressing, as typically occurring under the IT, would correlate in RSD to the pain relieving effect following a diagnostic guanethidine blockade. For this purpose, both IT and guanethidine blockade were applied to 40 RSD-patients. A high correlation was found between the results of both procedures: 89% of those cases, who showed a positive IT (38 out of 40 patients) also reported acute pain relieve following the guanethidine blockade. Thus, both procedures have the same diagnostic value for pain in RSD. These results are in agreement with new pathophysiological considerations, assuming an indirectly (via the microvascular system) mediated sympathetic-afferent coupling as a cause of pain in RSD.