IVIG Cuts Pain Intensity in Complex Regional Pain Syndrome

Patients with long-standing complex regional pain syndrome (CRPS) experienced significantly reduced average pain intensity after a single infusion of intravenous immunoglobulin (IVIG), according to a report by researchers at the University College London Hospitals Pain Management Center. Twelve patients suffering with CRPS for six to 30 months were randomly assigned to receive 0.5 grams/kg of IVIG or an equal volume of normal saline. After a washout period of at least 28 days, each patient was then crossed over to the alternative treatment.

Asked to rate their pain intensity on a zero-to-10 point rating scale, patients rated their pain experience 1.55 units lower during the six to 19 days following IVIG therapy than after saline injection (95% CI, 1.29 to 1.82; P < 0.001). In three of the 12 patients, reported pain intensity following IVIG administration was less than after saline by 50 percent or more. No serious adverse reactions to IVIG were reported.

While acknowledging that recruitment bias and chance variation could have influenced results in this small trial, the investigators noted that the observed response rate to IVIG in this crossover trial is consistent with results from a 2005 study evaluating IVIG in 130 patients with 12 chronic pain syndromes.