C diff for about 3 months.found out last month and neither 2 antibiotics worked.now my gi wants a colonoscopy.how will this help? what can show up?

Diagnostic: It sounds like you might have been left with unexplained symptoms. It is not usual for C diff not to respond to Flagyl and/or Vanco. Colonoscopy is needed most likely in order to visualize macroscopic changes and/ or to rule out colitis as the possible cause for your symptoms. Biopsies might be taken during the procedure. Protracted symptoms are seen in treated C diff colitis.