Hi WordWarriorMama and welcome to NeuroTalk!
We're sorry that you have a reason to be here but happy to meet you!
I'm also sorry to hear that you are in a relapse. It has to suck after being relapse free for so long.

Now down to business. I'm not a doctor. The only thing I can tell you is to talk to your neuro at length. Ask why he/she thinks you are in relapse and that it is not PML. While most neurologists look at the MRI report, a lot of them do not look at the actual MRI. I would hope that your neuro would have done this since you are a patient on Tysabri. Ask if the radiologist who read the MRI has experience in PML lesions and their presentation on MRI as opposed to MS lesions.

Perhaps you could give the radiologist a call and talk to them directly just to reassure yourself. I did this with the chief radiologist at my medical center and he gave me a crash course in the difference between MS lesions and PML lesions and their presentation, and it made me feel a whole lot more secure in that he knew what he was looking for and more importantly, WHY that was important when it comes to Tysabri patients. There is usually a difference between the two types of lesions and a radiologist can explain the difference. At one time, the medical community thought that all PML lesions were non-enhancing but that has proven to be false and it's important for a radiologist to know what they are looking for.

You don't say when your last infusion was. Did you skip the last infusion or have it? Were you feeling as if this was started before your last infusion? Did you talk to your neuro as soon as you noticed a change? Has your neuro talked to you about the JCV assay that is coming out?

I know I asked a lot of questions and that it's not easy to answer some of them when you are relapsing, sorry for that.

It's not unusual to feel worse before you feel better when in relapse and doing steroids. I know for me, the steroids always make me feel worse and it always took me a long time to see improvement even after doing the steroids. I haven't had a relapse since I started Tysabri but I know that there is always a chance that I will have a relapse since Tysabri is designed to reduce the number of relapses, not stop them entirely. I've almost forgotten what it's like to have a relapse, but not entirely.
You are correct in that a lot of us get hit cognitively, for me it was the cognitive stuff that irked me the most of all my symptoms and I don't want to go through that again!

I hope that you come through this ok and that you go on to have better days. Please let us know how it goes for you. We're all in this together, learning the process even after several years in many of our cases, so come back and let us know! We're pulling for you!