If you have or have access to the original PDF (if that's what it was) then you could rescan using the Abbyy Fine Print software - most of the aficionados seem to think it's the best of breed.
Have you looked at this ==>>
Function Mode for Search & Replace in the Editor. I suspect it could be used do what you want (maybe wrapped in an editor PI). But as it was only released last week I would guess there's not a very large body of expertise in its usage as yet.
BR