Pira
Has anyone heard of Pira? (Progression Independent of Relapse Activity (PIRA) refers to the gradual worsening of disability in multiple sclerosis (MS) that occurs independently of acute relapses.) I think I might have this but am hesitant to bring this up with consultant if it's not real

I certainly have! PIRA (Progression Independent of Relapse Activity) was explained to me as a reason for my deterioration, despite my MRIs showing no new lesions.
That was by my Consultant Neurologist. Apparently it's a relatively new concept and first appeared in a Medical Journal in 2018 (if I remember correctly).