Plasma exchange, also known as plasmapheresis, is a way to "clean" your blood. It works sort of like kidney dialysis. During the treatment, plasma -- the liquid part of your blood -- gets replaced with plasma from a donor or with a plasma substitute.

People with some forms of multiple sclerosis use plasma exchange to manage sudden, severe attacks, sometimes called relapses or flare-ups. Their plasma could have certain proteins that are attacking their own body. When you take out the plasma, you get rid of those proteins, and symptoms may get better.

How It Works

You can get plasma exchange in the hospital or at an outpatient center. The process isn't painful, and you won't need anesthesia.

You'll lie in bed or sit in a reclining chair.

A nurse or a specialist will put a needle attached to a thin tube, called a catheter, into a vein in each arm. If your arm veins are too small, you may have to have a needle in your shoulder or groin instead.

Your blood comes out through one of the tubes and goes into a machine that separates your plasma from your blood cells. Then your blood cells get mixed with fresh plasma, and the new blood mixture goes back into your body through the other tube.

Most treatments last 2 to 4 hours, depending on how big your body is and how much plasma gets swapped out. You may need two or three treatments each week for 2 or more weeks.

Side Effects and Risks

During plasma exchange, your blood pressure is lower than usual. This can make you feel weak, dizzy, or nauseous. Drink lots of water in the days before your treatment, because that can help prevent these symptoms.

You may feel tired after plasma exchange, but most people can get back to their normal activities right away.

Plasma exchange can cause bleeding and allergic reactions, and it can make your chance of getting an infection higher. In rare cases, a blood clot could form in the machine.

Who It Helps

Your chance of seeing improvement of MS symptoms is greater if you have a relapsing form of MS and:

  • You're a man.
  • You have Marburg variant MS.
  • Treatment begins within 20 days after your symptoms start.

But simpler, less costly treatments often work for MS, so your doctor will probably try those first. For a severe MS attack, your doctor will probably prescribe high doses of anti-inflammatory steroids. If that doesn't relieve your symptoms, then plasma exchange is a short-term option.

Plasma exchange hasn't been shown to help primary progressive or secondary progressive MS.

It may also help treat other diseases that damage the coating around your spinal cord and nerves, such as Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and myasthenia gravis. After plasma exchange, people with Guillain-Barré syndrome or chronic inflammatory demyelinating polyneuropathy are more likely to regain muscle strength and walk without help.

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