Complex Regional Pain Syndrome (CRPS) is a multi-symptom, multi-system syndrome that remain poorly understood. As I have mentioned previously , it was called reflex sympathetic dystrophy (RSD) when I first learned about it. I still catch myself calling it RSD.
For a complete review of CRPS, please refer to my previous post on the topic. This post is to look at an article published in the February issue of the journal Annuals of Internal Medicine (full reference below).
A research team at the Pain Research Institute at the University of Liverpool note that there is some evidence for “for immune activation in the affected limb, peripheral blood, and cerebrospinal fluid.”
This lead them to conduct a randomized, placebo-controlled, double-blind, single-center, 2-period crossover trial study. The study included13 eligible participants were randomly assigned between November 2005 and May 2008; 12 completed the trial. Participants were selected from confirmed CRPS patients who had pain intensity greater than 4 on an 11-point (0 to 10) numerical rating scale and had CRPS for 6 to 30 months that was refractory to standard treatment.
They found that a single, low-dose infusion of intravenous immunoglobin (IVIG) provided significant pain relief in nearly 50 percent of patients treated. IVIG is a blood product that contains immunoglobulin G extracts from the plasma of more than 1,000 blood donors. It is used to treat inflammatory and autoimmune diseases, immune deficiencies, and acute infections. In this study, the pain relief lasted on average five weeks.
The editors of the Annuals make the point I want to stress:
Because the study is so small, it is difficult to know whether these results apply to most other patients with CRPS. Also, the small number of patients increases the possibility that chance may affect the results.
For now, the cornerstone in the treatment of RSD / CRPS remains normal use of the affected part as much as possible. This is done through education, pain control, and physical therapy. (photo credit)
For more information check this eMedicine article and this website (RSD Foundation). You will also find a nice video animation on the RSD Foundation site that shows how an injury might trigger RSD / CRPS.
Intravenous Immunoglobulin Treatment of the Complex Regional Pain Syndrome: A Randomized Trial; Ann Intern Med. 2010;152:152-158; Goebel A, Baranowski A, Maurer K, Ghial A, McCabe C, Ambler G