IASP diagnostic criteria for Complex Regional Pain Syndrome: A preliminary empirical validation study

Objective: To assess the ability of the international Association for the Study of Pain Complex Regional Pain Syndrome (CRPS) diagnostic criteria and associated features to discriminate between CRPS patients and patients with painful diabetic neuropathy. Design: Prospective assessment of signs and symptoms in a series of CRPS and diabetic neuropathy patients. Setting: University of Washington Multidisciplinary Pain Center. Patients: A consecutive series of 18 CRPS patients and 30 diabetic neuropathy patients. Interventions: Patients completed a 10-item patient history questionnaire assessing symptoms of CRPS prior to medical evaluation. The evaluating physician completed a 10-item patient examination questionnaire assessing objective signs of CRPS. Outcome Measures: The analyses conducted were designed to test the ability of CRPS signs and symptoms and associated features to discriminate between CRPS patients and diabetic neuropathy patients. Results: Data analysis suggested that CRPS decision rules may lead to overdiagnosis of the disorder. Diagnosis based on self-reported symptoms can be diagnostically useful in some circumstances, The addition of trophic tissue changes, range of motion changes, and "burning" quality of pain did not improve diagnostic accuracy, but the addition of motor neglect signs did. Test of a CRPS scoring system resulted in improved accuracy relative to current criteria and decision rules. Conclusions: Poorly understood disorders lacking prototypical signs/symptoms and diagnostic laboratory testing must rely on the development of reliable diagnostic guidelines. The results of this study should assist in the further refinement of the CRPS diagnostic criteria.