Treating Myasthenia Gravis with Plasmapheresis and IVIG

Reviewed by: HU Medical Review Board | Last reviewed: September 2023

When the muscle weakness of myasthenia gravis (MG) is slowly getting worse over days to weeks, it is called a flare. If the weakness is sudden or severe, it is called a myasthenic crisis.

There are 2 treatments doctors can use when the muscle weakness of myasthenia gravis (MG) is getting worse and the person’s regular drugs are not working. These treatments are plasma exchange and intravenous immune globulin (IVIG).1

Plasma exchange and IVIG are sometimes called “rescue” or “bridge” therapies. This is because these treatments work quickly to improve serious muscle weakness. This provides a rescue or bridge until the person’s new medicines can start working.1

Plasma exchange and IVIG may also be used before surgery to boost the immune system and help prevent complications during and after surgery. It may also be used in people who need to avoid or reduce the amount of steroids they are taking.1

What is plasma exchange?

Plasma exchange is also called plasmapheresis (plaz’ ma pha ree’ sis). It is a type of transfusion in which a person’s plasma is removed and replaced with plasma from a healthy donor or other fluid.2

Plasma is the part of the blood that is left when red blood cells, white blood cells, and platelets have been removed. Plasma makes up about 55 percent of blood, and it contains water, salts, enzymes, antibodies, and other types of proteins. The contents of plasma help the blood clot and the body fight infection, among other jobs.2

How does it work in people with MG?

The idea behind plasma exchange is that the plasma of a person with MG contains antibodies that attack the body’s healthy tissue. Plasma exchange replaces their plasma with healthy plasma, which reduces both pathogenic and protective antibody levels.1

Muscle weakness usually gets better within days, but the effects only last for 3 to 6 weeks. Antibody levels will rebound unless the person begins taking an immunosuppressant like a steroid or other drug that changes how the immune system acts (immunosuppressants and immunomodulators). Most people receive 5 exchanges over 1 to 2 weeks, given through an intravenous line (IV).1

The most common side effects of plasma exchange include:1

  • Bleeding
  • A drop in blood pressure
  • Arrhythmia (irregular heartbeat)
  • Muscle cramps
  • Allergic reaction to chemicals used in the exchange

Doctors generally avoid using plasma exchange long-term because frequent use causes veins to collapse. When this happens, a long-term catheter or port must be installed to deliver the fluid, which adds a risk of infection.1

What is intravenous immune globulin (IVIG)?

Like plasma exchange, intravenous immune globulin (IVIG) is used to quickly reverse muscle weakness during an MG flare or myasthenic crisis. Immune globulin (immunoglobulin) are healthy antibodies pooled from thousands of healthy donors. These healthy antibodies are delivered through an intravenous line (IV) over 2 to 5 days.1

MG symptoms usually improve in less than a week, and benefits last for 3 to 6 weeks. The most common side effects of IVIG are mild and include:1

  • Headache
  • Chills
  • Dizziness
  • Fluid retention

These side effects are generally managed by slowing the rate of IVIG flowing into the person’s body.3

IVIG may also be used instead of plasma exchange, in people with refractory MG, before thymectomy surgery, or as a bridge until immunosuppressant drugs start to work.1

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