Interaction of Hyperalgesia and Sensory Loss in Complex Regional Pain Syndrome Type I (CRPS I)

Volker Huge,Stefanie Förderreuther,Meike Lauchart,Walter Magerl,Wibke Kaufhold,Michael Valet,Antje Beyer,Shahnaz Christina Azad,Allan Cyna

doi:10.1371/journal.pone.0002742

Abstract

BackgroundSensory abnormalities are a key feature of Complex Regional Pain Syndrome (CRPS). In order to characterise these changes in patients suffering from acute or chronic CRPS I, we used Quantitative Sensory Testing (QST) in comparison to an age and gender matched control group.Methods61 patients presenting with CRPS I of the upper extremity and 56 healthy subjects were prospectively assessed using QST. The patients' warm and cold detection thresholds (WDT; CDT), the heat and cold pain thresholds (HPT; CPT) and the occurrence of paradoxical heat sensation (PHS) were observed.ResultsIn acute CRPS I, patients showed warm and cold hyperalgesia, indicated by significant changes in HPT and CPT. WDT and CDT were significantly increased as well, indicating warm and cold hypoaesthesia. In chronic CRPS, thermal hyperalgesia declined, but CDT as well as WDT further deteriorated. Solely patients with acute CRPS displayed PHS. To a minor degree, all QST changes were also present on the contralateral limb.ConclusionsWe propose three pathomechanisms of CRPS I, which follow a distinct time course: Thermal hyperalgesia, observed in acute CRPS, indicates an ongoing aseptic peripheral inflammation. Thermal hypoaesthesia, as detected in acute and chronic CRPS, signals a degeneration of A-delta and C-fibres, which further deteriorates in chronic CRPS. PHS in acute CRPS I indicates that both inflammation and degeneration are present, whilst in chronic CRPS I, the pathomechanism of degeneration dominates, signalled by the absence of PHS. The contralateral changes observed strongly suggest the involvement of the central nervous system.

Highlights

Complex Regional Pain Syndrome (CRPS) is a neuropathic pain disorder, evolving after limb trauma either without (CRPS I), or with definable nerve lesion (CRPS II) [1]
Patients and Control Subjects There was no difference in mean age between Complex Regional Pain Syndrome Type I (CRPS I) patients and healthy subjects, both groups exhibited normal distributions of age
No differences were found concerning the levels of pain as well as depression between acute and chronic CRPS patients (Table 2)

Summary

Introduction

Complex Regional Pain Syndrome (CRPS) is a neuropathic pain disorder, evolving after limb trauma either without (CRPS I), or with definable nerve lesion (CRPS II) [1]. Autonomic, trophic and motor disturbances, sensory abnormalities are key symptoms of CRPS [2], typically not confined to the innervation territory of peripheral nerves or nerve roots. CRPS sensory abnormalities may spread in a hemisensory manner [3] or even contralaterally [4]. Sensory abnormalities are a key feature of Complex Regional Pain Syndrome (CRPS). In order to characterise these changes in patients suffering from acute or chronic CRPS I, we used Quantitative Sensory Testing (QST) in comparison to an age and gender matched control group

Objectives

Methods

Results

Discussion

Conclusion