Secondary complex regional pain syndrome is significantly more likely in people currently experiencing CRPS in an unrelated extremity than in the general population, according to Ellen Satteson, MD, and her associates.
In a study of 93 patients with CRPS, 20.4% developed secondary CRPS in another extremity. Twenty patients in the primary CRPS group experienced a secondary inciting event. Of this group, 75% developed secondary CRPS. CRPS in all four extremities occurred in six patients, of whom five had inciting events for each extremity.
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The odds ratio for secondary CRPS in the study group compared to the general population was found to be 1,069.6, while the OR for CRPS after an inciting event compared to the general population was 11.7.
“An odds ratio of over 1,000 when comparing the reported population incidence of CRPS to the rate of secondary CRPS documented in this study strongly suggests that patients with a history of CRPS may be at considerable risk of developing secondary CRPS ... Additional, prospective studies with standardized follow-up to assess for subsequent injuries and secondary CRPS, however, are needed to better elucidate the significance of this risk,” the investigators noted.
Find the study in the Scandinavian Journal of Pain (doi: 10.1016/j.sjpain.2016.10.005).