My internist told me that the antibiotic flagyl I took to get rid of my C-diff would not help a sinus infection. I always thought an antibiotic was good for every thing with some better than others, depending on what was wrong with you.
I just got over a C-diff infection that took 2 rounds of flagyl to kill. She didn't want to put me on an antibiotic because the kind I need for my sinus infection could cause my C-diff to flare up again.
So if you start with the big D again it could be pouchitis, cuffitis and/or a C-diff infection. I had C-diff along with cuffitis and my GI caught it when he did the flex scope. Along with biopsies he also had a stool sample tested.
You should get a scope please make sure it is a flex scope and not a straight scope. My surgeon had me come in after a year and he did a straight scope which is fast but painful and he didn't have the capability to take biopsies.
I'm just adding this about the straight scope as I didn't know if you would go to your surgeon or GI.