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The following is a summary of “Early CRPS Is a Heterogeneous Condition: Results From a Latent Class Analysis,” published in the January 2025 issue of Pain by Louis et al. 

Complex regional pain syndrome (CRPS) is a debilitating condition with significant heterogeneity, and early diagnosis is crucial, though limited data exists on its initial stages.  

Researchers conducted a retrospective study to characterize patients with very early CRPS and explore potential subgroups to enhance understanding of its mechanisms.  

They recruited 113 patients with CRPS, and 89 participants undergoing physical assessments. Data collected included demographic information, work-related factors, CRPS history and clinical features, body perception disturbances, quantitative sensory testing (QST), and a visuospatial attention task.  

The results showed that QST revealed deficits in detecting thermal and mechanical stimuli, with increased sensitivity to thermal and blunt pressure pain. Participants reported body perception disturbances similar to persistent CRPS. Visuospatial biases were identified in 2 patient subgroups. Latent class analysis (LCA) of 85 participants, based on 5 clinical parameters, identified 4 profiles: Mild, Moderate, Body Representation Disturbance (BRD), and Pressure Allodynia CRPS. The Mild and Moderate profiles were linked to higher trauma intensity, with Moderate showing worse outcomes. The BRD and Pressure Allodynia CRPS followed mild trauma but had the poorest outcomes, BRD CRPS exhibited significant body perception disturbances, while Pressure Allodynia CRPS showed the highest-pressure sensitivity and psychosocial risk of chronification. Neither condition duration nor skin temperature effectively differentiated subgroups.  

Investigators concluded the heterogeneity within very early patients with CRPS, supporting the absence of a mandatory diagnostic delay and suggesting that central and systemic mechanisms might play crucial roles in developing severe disease. 

Source: onlinelibrary.wiley.com/doi/abs/10.1002/ejp.4785