Hello..... I have RA (dx 10 yrs ago) been living with it since I was 12 years old.... Go Figure, and I have had seizures as well - but IMO the RA is not the cause of the seizures, but rather a symptom maker, for as you said RA does and will effect many diff organs in the body, as all autoimmune diseases do.
I personally already have 3 autoimmune diseases to cope with and they might be adding a third to the list (Lupus), after I am tested for it on Feb 2, 2007 by my Rheumy doctor.
Hang in there and cont' to write and release your worries & concerns here.
Rhapsody -