The Warm Phase of CRPS Type-1: Is It Time to Review the Budapest Criteria?

Complex Regional Pain Syndrome (CRPS) type 1 is a painful and disabling localized syndrome with a pathogenesis that is still unclear. The last revised diagnostic criteria for CRPS-1 syndrome were developed in 2012 (the so-called Budapest criteria), based only on clinical features, while the presence of bone marrow edema (BME) and the response to treatments were completely absent. As BME is usually present on magnetic resonance imaging (MRI) in the early ("warm") phase of CRPS-1, this criterion should be added as a necessary criterion to Budapest criteria. In addition, hyperalgesia and/or allodynia are also commonly present in the warm phase. Therefore, both of these symptoms should be included as essential criteria. Furthermore, the response to bisphosphonates may be another important parameter to add to the list of treatment options, as well as hyperbaric oxygen therapy. Finally, it must be clear that BME is not an exclusive finding of CRPS-1. Therefore, a correct clinical history and, if needed, further radiological studies and laboratory tests should be performed to avoid a false diagnosis. In this paper, the "Bone Marrow Edema Diagnosis and Therapeutic Treatment" Italian Group (GEODEIT) proposes a revision of Budapest's criteria to make them more meaningful and effective in reaching a correct and quick diagnosis of the disease.