Characteristics of complex regional pain syndrome in patients referred to a tertiary pain clinic by community physicians, assessed by the Budapest clinical diagnostic criteria.

Objective: The aim of this study was to describe the characteristics of patients referred with complex regional pain syndrome (CRPS) diagnosis to a tertiary care pain center.

Method: Descriptive chart review study of all patients referred by family physicians or community specialists as having CRPS (2006-2010). Data extraction included demographics, pain ratings, and diagnosis utilizing the Budapest CRPS criteria.

Results: The study population consisted of 54 subjects (male [M] =7, female [F] =47). Only 27.7% were classified as CRPS by the clinical expert. Four additional subjects carrying other diagnoses but found to have CRPS were added to the analysis. The non-CRPS group consisted of 39 subjects (M=8, F=31) and the CRPS group of 19 (M=2, F=17). CRPS patients were statistically significantly more likely to 1) have suffered a fracture; 2) report symptoms in each of the four symptom categories, as well as signs in three or four categories collectively; and 3) have allodynia/hyperalgesia alone or in combination (85/90%) as compared with the non-CRPS group (23/25%, respectively). The non-CRPS group was much more likely to report no symptoms or signs at all in the different symptom and sign categories. Of the 39 non-CRPS patients, 74% had other diagnosable entities (1/3 suffering from specific neuropathic pain conditions, e.g., radiculopathy, diabetic neuropathy, etc. and 2/3 from discreet musculoskeletal entities), while 18% were diagnosed with psychogenic pain disorders including conversion reaction associated with immobility or paralysis.

Discussion: Besides fulfilling the Budapest CRPS diagnostic criteria, the most important other factor for diagnosing CRPS is the exclusion of a neuropathic, musculoskeletal, or non-biomedical condition accounting for the presentation.