Carol, did you sort out the cat problem?  Does your cat lick itself a lot?  I found out that along with the cinusitis, I've been treating my cat for hypertension for three months.  Her heart condition was affecting her sinuses to the point that she couldn't breathe properly.  The vet said we need to stop the meds or she will be on them for life.  So we've had a few rough days, but what I noticed was that she would constantly lick herself.  This in turn flared up her breathing problems (I live in Taiwan and there is a lot of air dust).  To control the constant licking, I just put a plastic cone on her neck.  She couldn't lick and wasn't happy about the cone.  So she sat and relaxed (albeit a bit depressed).  I left her for a day with the cone.  The next morning I took it off and she's been calm, not licking like crazy, breathing clearly and playing naturally for two days.  Maybe this can help your cat.  Often heart problems will affect their breathing and sinuses.