However, plasma exchange is recommended as a second-line treatment for relapses that have not responded to a course of Solu-Medrol -- not instead of Solu-Medrol.
The endorsement from the AAN for treatment of relapses in RRMS was made in January 2011 and is a change to the guidelines from 1996, where the procedure was referred to only as "promising" and "possibly useful."
It should be noted that plasma exchange is NOT recommended by the AAN to treat secondary progressive or primary progressive multiple sclerosis.
Why Would Plasma Exchange Work for Relapses?
Plasma exchange removes harmful substances that are circulating in the liquid portion (the plasma) of the blood. In the case of MS, this is probably antibodies against the protein that makes up myelin, as well as T cells and possibly other immune cells that may target myelin.
It is thought that removing these cells during a relapse could limit the duration of the relapse and the damage caused by inflammation. However, once these antibodies are sequestered or deposited in the lesions, plasma exchange can no longer remove them and it will probably not have any treatment benefit.
What is the Evidence for Plasma Exchange for RRMS Relapses?
In one small crossover trial, 22 people with RRMS or other inflammatory demyelinating diseases (transverse myelitis, neuromyelitis optica) that cause acute symptoms were included in a study of plasma exchange. All people had failed to respond to a course of Solu-Medrol and the average score on the EDSS was 7.5 when they started the treatment. Nine patients had "marked" to "moderate" improvement after plasma exchange. Five of these continued to experience improvement for up to 3 years.
In another small group of cases, four people with RRMS had relapses that did not respond to Solu-Medrol. Each was given 5 cycles of plasma exchange. One person had "marked" recovery, 2 people had "moderate" recovery (although one of them required that the 5-cycle treatment be done twice), and one person had "mild" recovery.
Bottom LineIf you are having a severe relapse that is not responding to Solu-Medrol, your doctor may very well suggest plasma exchange. Plasma exchange is a relatively safe procedure that is non-invasive and does not cause much discomfort.
NOTE: Plasma exchange is also used in people with multiple sclerosis who are diagnosed with Tysabri-associated progressive multifocal leukoencephalopathy (PML). It is often used in combination with medications. (To learn more: Q. What is the treatment for Tysabri-related PML?)
For an overview of the plasma exchange procedure, read: Plasma Exchange (Plasmapheresis) for MS and Other Neurological Diseases
Cortese I, Chaudhry V, So YT, Cantor F, Cornblath DR, Rae-Grant A. Evidence-based guideline update: Plasmapheresis in neurologic disorders: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. 2011 Jan 18;76(3):294-300.
Habek M, Barun B, Puretic Z, Brinar VV. Treatment of steroid unresponsive relapse with plasma exchange in aggressive multiple sclerosis. Ther Apher Dial. 2010 Jun;14(3):298-302.
Lehmann HC, Hartung HP, Hetzel GR, Stuve O, Kieseier BC. Plasma Exchange in Neuroimmunological Disorders, Part 1: Rationale and Treatment of Inflammatory Central Nervous System Disorders. Arch Neurol. 2006;63:930-935.
Weinshenker BG, O'Brien PC, Petterson TM, et al. A randomized trial of plasma exchange in acute central nervous system inflammatory demyelinating disease. Ann Neurol. 1999;46:878-886.