myasenthia gravis or lupus?

I am a 28 yr old female and mother of four small children. I am currently being seen by a Rheumatologist for possible lupus or Sjogren's syndrome, but I do not have a definitive diagnosis due to nonspecific blood tests. The only thing I tested positive for was P-ANCA with borderline MPO anitbody.

Over the past year I have also developed neurological symptoms in addition to the hair loss, rashes, joint pain, fatigue, oral ulcers, dry mouth/skin, dental problems, and Raynauds.

I have had several episodes of numbness and tingling of my limbs. It will be just my left leg or one of my arms. It will last for at least a day and up to a week. I also started having cognitive problems of using the wrong word for things, problems with memory, confusion, etc. My vision has gotten much worse over the last few months and is very foggy and blurry. I am having trouble chewing. My muscles get so tired from chewing a peice of gum for even five minutes.

The worst part is I have started having trouble walking and using my arms. If I walk more than a few steps my legs feel like they are going to collapse. I have been losing my balance and banging into things constantly.

The scariest part is my left arm is progressively getting weaker and weaker. I can hardly use it any more. I can't grip and open lids or twist things. I am also dropping things constantly. My left hand has also developed a shaking or tremor when I flex my wrist.

Do these symptoms sound like things that could be part of lupus or that it might be something else like MG. My PCP thought it was MS, but with a normal MRI, she said it was not. I have an appt to see a neurologist next week. What might I expect?

Thank you so much.

Andrea