Plasma Exchange Effective in a Subset of Patients with Complex Regional Pain Syndrome

Usually developing following trauma, complex regional pain syndrome (CRPS) has been postulated to be associated with distal degeneration of small-diameter peripheral axons. Based on a recent hypothesis proposing an autoimmune etiology for CRPS and reported efficacy of intravenous immune globulin (IVIG) therapy in some patients, investigators at Drexel University College of Medicine in Philadelphia have recently offered plasma exchange (PE) to CRPS patients with a clinical presentation suggestive of a small fiber neuropathy. A retrospective case series study evaluated 33 CRPS patients who received between five and 11 (mean 7.2) PE treatments over a two- to three-week period.

Thirty of the 33 patients demonstrated significant median pain reduction of 64 percent (P < 0.01) following the initial series of PE treatments. Three patients demonstrated no improvement. Twenty-four patients are receiving maintenance therapy, with pain reduction following the initial PE series maintained with either weekly PE (n = 15), oral immune modulating agents (n = 8) or IVIG (n = 1). The remaining six patients did not receive maintenance therapy, and their pain has returned to pre-treatment levels.

Analysis of the study findings suggests that patients with the greatest loss of small fibers and greatest temperature sensory deficits are most likely to benefit from PE therapy. The investigators suggest that large, randomized, placebo-controlled studies may be required to confirm and expand their results.