Hi,
I have CIDP. Common CIDP. I have tried every treatment available, or nearly. Plasmapheresis is a rather targeted treatment that removes plasma (b cells) from the blood. Usually performed with a central line, I've tried peripheral as well. It's done over a period of 5 consecutive days. That's the absolute maximum targeted dose in order to give the immune system a "clean slate". Then you wait. Some times it shows improvement in certain symptoms or an overall positive effect. It may happen while you're undergoing plasmapheresis treatment or up to 2-3 weeks post treatment. That has been my experience. Your neurologist should be able to give you his response on the possible effects of plasmapheresis for your particular case. CIDP tends to be very case sensitive. Overall, plasmapheresis tends to give good, rather immediate results and works for many. Typically. neurologists will start treatment with steroids then move to plasmapheresis, then IVIG, then Rituximab and so on. Wish your son the best while undergoing treatment and hope they come up with a definitive diagnosis so that they can apply proper treatment. That would be helpful all around. Patience and a positive outlook. The doctors will usually find what works and will ultimately be able to help him. It could be a single line treatment or a combination. All the best.