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.