Susan Collins

Diagnostic criteria for CRPS I: differences between patient profiles using three different diagnostic sets.

Complex Regional Pain Syndrome type I (CRPS I) is an illness which usually occurs due to major or minor tissue injury to the extremities. Because a unique pathophysiological mechanism for CRPS I has not yet been established, the diagnosis is based on observation and measurement of clinical symptoms and signs. In this study, a comparison was made between three sets of diagnostic criteria (the IASP, Bruehl et al. and Veldman et al.) based on patient reports and physicians’ assessments of signs and symptoms associated with CRPS I, in 372 outpatients suspected of having CRPS I. Agreement between CRPS I diagnosis among the three sets was poor (κ‐range: 0.29–0.42), leading to positive CRPS I diagnoses according to Veldman et al.s criteria in 218 cases (59%), according to the IASP in 268 cases (72%), and according to Bruehl et al. in 129 cases (35%). Significant differences in patient profiles were found between the diagnostic sets for the number of patients reporting continuing disproportionate pain, larger area affected than the initial trauma (both p<0.001), increase of symptoms due to exercise (p=0.009), edema (p=0.015), temperature asymmetry (p=0.015), hyperesthesia, allodynia (both p<0.001) and hyperalgesia (p=0.036). Similarly, significant differences emerged for physicians’ observations of hyperesthesia and allodynia (both p<0.001). Highest combined values of sensitivity (SE) and specificity (SP) for the strongest cases of presence (n=108) or absence (n=62) of CRPS I were found for reported hyperesthesia (SE+SP:165%), allodynia (160%), observed color asymmetry (162%), hyperesthesia (157%), temperature asymmetry (154%) and edema (152%). The lack of agreement between the different diagnostic sets for CRPS I and the different clinical profiles that result from it may lead to different therapeutic and study populations, hampering adequate treatment and scientific development for this illness. We propose explicit reference to diagnostic criteria used in studies, and registration in trials of a broad variety of CRPS I features, as used in this study, to make subgroup phenotyping and post hoc analyses based on different diagnostic criteria possible.

Intravenous Magnesium for Complex Regional Pain Syndrome Type 1 (CRPS 1) Patients: A Pilot Study

OBJECTIVES To explore the feasibility of intravenous magnesium administration as a potential candidate intervention for a large size trial in Complex Regional Pain Syndrome Type 1 (CRPS 1). DESIGN Randomized clinical trial. SETTING Outpatient pain clinic. PATIENTS Ten CRPS 1 patients. INTERVENTIONS Eight patients received 70 mg/kg magnesium sulphate infusions in 4 hours for 5 days. For blinding purposes, 2 patients received equal amount NaCl 0.9% solutions (data not analyzed or presented). Interventions were accompanied by standardized physical therapy. OUTCOME MEASURES Pain was assessed using an 11-point Box scale (three times daily for a week) and the McGill Pain Questionnaire. Skin sensitivity was measured with the Semmes Weinstein Monofilaments, (other) impairments with the Impairment Level Sumscore. In addition, functional limitations (Radboud Skills Questionnaire, questionnaire rising and sitting down) and quality of life (Short Form-36 [SF-36], EuroQol) were evaluated. Assessments were performed at baseline, 1, 3, 6, and 12 weeks after intervention. RESULTS Mild systemic side effects were experienced and the infusions were locally well tolerated. Pain was significantly reduced at all follow up compared with baseline (T1: P = 0.01, T3: P = 0.04, T6: P = 0.02, T12: P = 0.02). McGill sensory subscale improved significantly at T1 (number of words chosen: P = 0.03 and pain rating index: P = 0.03). Impairment level (P = 0.03) and quality of life (EuroQol P = 0.04, SF-36 physical P = 0.01) were significantly improved at T12. No improvement was found for skin sensitivity and functional limitations. CONCLUSION Intravenous magnesium significantly improved pain, impairment and quality of life and was well tolerated. The results of this pilot study are encouraging and suggest that magnesium IV as a treatment in CRPS 1 should be further explored in a large size formal trial design.

Intravenous magnesium for chronic complex regional pain syndrome type 1 (CRPS-1).

OBJECTIVE To assess the effects of intravenous administration of magnesium on complex regional pain syndrome type 1 (CRPS-1), a randomized double-blind placebo-controlled trial was performed. METHODS Fifty-six patients with CRPS-1 (International Association for the Study of Pain Orlando criteria) received MgSO(4) 70 mg/kg or placebo (NaCl 0.9%) in 4 hours over 5 consecutive days. Pain (BOX-11 and McGill), the level of impairment (Impairment level Sum Score [ISS]), functional limitations (Radboud Skills Questionnaire, Walking Skills Questionnaire/questionnaire rising and sitting down), participation (Impact on Participation and Autonomy [IPA]), and quality of life (Short Form-36, EuroQol, IPA) were evaluated at baseline and at 1, 3, 6, and 12 weeks. RESULTS No significant differences were found between MgSO(4) and placebo on the BOX-11 and ISS at different time points during the trial on intention-to-treat and per-protocol analysis. A significant improvement on the BOX-11 was found after the first week of the trial in both groups (mean 0.7; standard deviation 1.1). For the MgSO(4) group, a clinically relevant and statistically significant improvement on the ISS at 1 week (median 5, interquartile range [IQR] -1 to 8) and a significant improvement on the McGill up to 6 weeks (median 2 words, IQR 0-4.5) were found compared with baseline, which were not found in the placebo group. Significant improvement in perceived job participation was found for the MgSO(4) group at 12 weeks (median improvement 1.44-1.17; P = 0.01). ISS improved significantly more in patients with a low Hospital Anxiety and Depression Scale (HADS) score (≤10) in the MgSO(4) group (mean 4.4 vs mean -3.1; P = 0.02). CONCLUSION Administration of the physiological competitive N-methyl-D-aspartate receptor antagonist magnesium in chronic CRPS provides insufficient benefit over placebo. Future research should focus on patients with acute CRPS and early signs and symptoms of central sensitization.

Development of a Symptoms Questionnaire for Complex Regional Pain Syndrome and Potentially Related Illnesses: The Trauma Related Neuronal Dysfunction Symptoms Inventory

OBJECTIVE To develop a questionnaire to evaluate symptoms of complex regional pain syndrome type I (CRPS-I), fibromyalgia, and repetitive strain injury to determine the test-retest reliability and investigate concurrence in the clinical manifestations of CRPS-I and fibromyalgia. DESIGN The Trauma Related Neuronal Dysfunction Symptoms Inventory (TSI) was developed by determining the content validity and the practical use of the questionnaire. Furthermore, the test-retest reliability was assessed on 2 identical questionnaires filled out within a 7-day interval by CRPS-I and fibromyalgia patients. SETTING Outpatient pain clinic of a Dutch medical center. PARTICIPANTS CRPS-I (n=26; mean age, 54y) and fibromyalgia patients (n=42; mean age, 45.4y). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE Test-retest reliability calculated with intraclass correlation (ICC). RESULTS Reliability scores were good for the whole questionnaire, its categories, and domains (ICC>.75) for both CRPS-I and fibromyalgia patients. Sensory complaints (except for change in cold perception), motor complaints, and visceral complaints (diarrhea and incontinence) were reported by both CRPS-I and fibromyalgia patients. A change in cold perception, discoloration, change in skin temperature, change in sweating behavior, change in the severity of edema during exercise, and trophic changes of skin were reported significantly more often by CRPS-I patients, whereas complaints of the (upper and lower) back, constipation, urine retention, and experiencing a dry mouth were reported significantly more often by fibromyalgia patients. CONCLUSIONS The TSI is a reliable instrument with good content validity, which can be used in the evaluation of similarities and differences between CRPS-I and fibromyalgia. The systematic evaluation of symptoms of CRPS-I and potentially related illnesses may provide a better basis for future research into the underlying mechanism(s).