Complex interaction of sensory and motor signs and symptoms in chronic CRPS.

Spontaneous pain, hyperalgesia as well as sensory abnormalities, autonomic, trophic, and motor disturbances are key features of Complex Regional Pain Syndrome (CRPS). This study was conceived to comprehensively characterize the interaction of these symptoms in 118 patients with chronic upper limb CRPS (duration of disease: 43±23 months). Disease-related stress, depression, and the degree of accompanying motor disability were likewise assessed. Stress and depression were measured by Posttraumatic Stress Symptoms Score and Center for Epidemiological Studies Depression Test. Motor disability of the affected hand was determined by Sequential Occupational Dexterity Assessment and Michigan Hand Questionnaire. Sensory changes were assessed by Quantitative Sensory Testing according to the standards of the German Research Network on Neuropathic Pain. Almost two-thirds of all patients exhibited spontaneous pain at rest. Hand force as well as hand motor function were found to be substantially impaired. Results of Quantitative Sensory Testing revealed a distinct pattern of generalized bilateral sensory loss and hyperalgesia, most prominently to blunt pressure. Patients reported substantial motor complaints confirmed by the objective motor disability testings. Interestingly, patients displayed clinically relevant levels of stress and depression. We conclude that chronic CRPS is characterized by a combination of ongoing pain, pain-related disability, stress and depression, potentially triggered by peripheral nerve/tissue damage and ensuing sensory loss. In order to consolidate the different dimensions of disturbances in chronic CRPS, we developed a model based on interaction analysis suggesting a complex hierarchical interaction of peripheral (injury/sensory loss) and central factors (pain/disability/stress/depression) predicting motor dysfunction and hyperalgesia

Interaction of hyperalgesia and sensory loss in complex regional pain syndrome type I (CRPS I)

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

Patient disposition.

<p>Disposition of patients eligible for the study. Eligible patients had been treated at the pain clinic and were diagnosed with chronic CRPS (Duration of disease more than 12 months).</p

Health related quality of life: (SF-36).

<p>The scales of the SF-36 score from 0–100, with 0 indicating worst health and 100 the best.</p><p>PF: Physical Functioning.</p><p>RP: Role Limitations, Physical:</p><p>BP: Bodily Pain.</p><p>GH: General Health.</p><p>VT: Vitality.</p><p>SF: Social Functioning.</p><p>RE: Role Limitations, Emotional.</p><p>MH: Emotional Well-Being.</p><p>PCS: Physical Component Summary Score MCS: Mental Component Summary Score.</p><p>t0: Before beginning of treatment.</p><p>t1: One year after beginning of treatment.</p><p>n.s.: Not significant.</p><p>Z-Score: SF-36 data were normalized to a US-General population (n = 2393).</p

Active range of motion.

a<p>Paired t-test.</p

(A) Paradoxical heat sensation (PHS) to mild cold stimuli as elicited by alternating cold and warm stimulation (TSL).

<p>PHS was a frequent finding in both hands in acute CRPS, and fully subsided in the chronic phase. Significance vs. controls: *** p<0.001; Significance vs. acute CRPS: ⁺⁺⁺ p<0.001; Significance vs. ipsilateral hand: ^(§) p<0.10, ^§ p<0.05. Note: Significance marks that bridge symbols of ipsilateral and contralateral hands apply to both hands. (B) PHS-positive CRPS patients (PHS+) exhibited a significantly more pronounced cold hyperalgesia than PHS-negative CRPS patients (PHS−). In contrast, there was no such difference in heat hyperalgesia. Error bars show 1SEM.</p

Thermal nociception in acute and chronic CRPS.

<p>HPT: Heat Pain Thresholds</p><p>CPT: Cold Pain Threshold</p

Proposed modified research diagnostic criteria for CRPS. ^*

*<p>Bruehl S, Harden RN, Galer BS et al. External validation of IASP diagnostic criteria for Complex Regional Pain Syndrome and proposed research diagnostic criteria. International Association for the Study of Pain. Pain 1999; 81: 147–154.</p

Michigan Health Questionnaire: (MHQ).

<p>Hand disability measured with MHQ: For the pain scale, higher scores indicate more pain. For the other scales, higher scores indicate better hand performance. Scores are normalized to a range from 0–100.</p