Gammunex-C, a form of intravenous immunoglobulin (IVIG), is approved for the treatment of chronic inflammatory demyelinating neuropathy (CIDP) or idiopathic thrombocytopenic purpura (ITP). IVIG has been in use for many decades in the treatment of these disorders and many other inflammatory/autoimmune diseases. It is generally very safe and well tolerated. More recently, IVIG has been proposed as an effective treatment for presumed inflammatory neurological disorders which do not meet the criteria for CIDP. Specifically, case reports and cases series have indicated therapeutic responses to IVIG in autonomic neuropathies.

Intravenous Albumin is approved for the treatment of hypovolemia (see attached package insert). The use of albumin to increase plasma volume in patients with POTS has been suggested. In this study, albumin will be used as an active control treatment to provide the same volume and protein load as IVIG but without the immunomodulatory effects.

There have been few well designed clinical therapy trials aimed at POTS patients and even fewer that are aimed at a particular pathophysiological subtype of POTS. Evidence suggests that POTS is a heterogeneous disorder with differing underlying mechanisms. Several uncontrolled case series have suggested a benefit of IVIG for POTS, but the volume expansion associated with infusion of IVIG make it difficult to assess the immunomodulatory effects of this treatment. We propose to evaluate the efficacy of IVIG using a double-blind randomized cross over design that will determine efficacy while reducing effects of inter-subject variability and placebo effect which are common problems in POTS therapy research. Even with the statistical advantages of a crossover design, the treatment cohort will be small, and this study is designed to be a pilot (phase II) study to evaluate the feasibility, tolerability and potential benefits of treatment. The results of this pilot study will provide the impetus and rationale for a larger multicenter clinical trial to definitively evaluate immunomodulatory treatment in POTS.