Complex Regional Pain Syndrome: Navigating Diagnostic Complexities.

Objective: Complex Regional Pain Syndrome (CRPS) presents significant diagnostic challenges due to its diverse clinical presentation. This study aims to describe the diagnostic trajectory of patients labeled with CRPS, focusing on referral patterns, application of the Budapest criteria, and accuracy of CRPS diagnosis.

Methods: A retrospective study was conducted of 53 patients treated for CRPS at a peripheral nerve clinic within a tertiary care center (2020-2024). Patient demographics, referral patterns, events leading to CRPS diagnosis, and diagnostic tests were analyzed. Three clinicians (two plastic surgeons, one pain medicine specialist) retrospectively assessed the validity of CRPS diagnoses using the Budapest criteria. Inter-rater reliability (IRR) for CRPS presence and type was calculated using Cohen's kappa (κ).

Results: Among the 53 patients, the median time from the first mention of CRPS to referral to the nerve clinic was 1.3 years (IQR:0.4-3.6). The Budapest criteria had been assessed in 26% of patients pre-evaluation. In 33% of patients labeled with CRPS type I, an inciting nerve injury was identified. Following retrospective assessment, 42% of patients were determined to have CRPS by all raters, 26% were determined not to have CRPS, and 32% showed inconsistent agreement. The IRR for CRPS diagnosis and type ranged from minimal to moderate (κ=0.32-0.72).

Discussion: Our findings highlight variability in the application of the Budapest criteria for CRPS diagnosis, as well as inconsistencies in its retrospective application. Potentially treatable peripheral nerve injuries should be addressed prior to CRPS diagnosis. These findings may help improve early diagnostic assessment in patients with chronic pain.