Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Center+, Maastricht, the Netherlands. Department of Rehabilitation Adelante/Maastricht University Medical Center+, the Netherlands. Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center+, Maastricht, the Netherlands. Department of Neurology, School of Mental Health and Neuroscience, Maastricht University Medical Center+, Maastricht, the Netherlands. email@example.com. Department of Neurology, Curaçao Medical Center, Willemstad, Curaçao.
OBJECTIVE This is the first double-blind, randomized, controlled trial evaluating the efficacy and safety of intravenous immunoglobulin (IVIg) versus placebo in patients with idiopathic small fiber neuropathy (I-SFN). METHODS Between July 2016 and November 2018, 60 Dutch patients with skin-biopsy proven idiopathic SFN randomly received a starting dose of IVIg (2 g/kg body weight) or matching placebo (0.9% saline). Subsequently,
3 additional infusions of IVIg (1 g/kg) or placebo were administered at 3-weekly intervals. The primary outcome was a 1-point change in Pain Intensity Numerical Rating Scale (PI-NRS) at 12 weeks compared to baseline. RESULTS Thirty patients received IVIg, and 30 received placebo. In both groups, 29 patients completed the trial. In 40% of patients receiving IVIg, the mean average pain was decreased with at least 1 point, compared to 30% of the patients receiving placebo (p-value 0.588, OR 1.56, 95%CI 0.53-4.53). No significant differences were found on any of the other pre-specified outcomes including general wellbeing, autonomic symptoms, and overall functioning and disability. CONCLUSIONS This RCT showed that IVIg treatment had no significant effect on pain in patients with painful idiopathic SFN.