Pseudomonas is usually an infection found in the ear
, not in the nose. So, no idea what it is doing there Lynette. But sure, it can cause a severe infection. And any severe infection will lead to inflammation, and that inflammation can lead to bone lysis and destruction. So, very likely.
Fluroquinolones often work. Orbax is a good medication for cats.
But, pseudomonas is probably not directly the cause of the erosin, but rather indirectly due to the inflammation. Does that make sense? And it could still be that there is a fungus or a tumor... etc. You just won't know unless fungal cultures are done, and a biopsy. *shrug* And even then...
But, pseudomonas, I can't tell you enough, is HARD to kill. Sometimes a nasal cream will have to be applied. In cats this is hard because it has to be done under sedation. Most cats aren't going to let you put something up their nose. BUT, in some cats you can do this.
Ceftazadime (Fortaz) seems to be a good choice for a systemic, injectible antibiotic as most pseudomonas organisms have never seen that antibiotic. SO, systemic injections might be an option as well. These are usually given IV but can be given in the muscle as well. The drug itself might be expensive and hard to get. It's not one that most vets will have sitting on the shelf, but it is an option to definitely consider and discuss with the Vet.
FOR IV use the pet would probably need to be hospitalized to make it easier. It is usually given IV with fluids. So, keeping a catheter in place is kind of hard in a cat at home. But, central lines into the jugular can be placed, and they last up to 7 days. Most vets do not have the ability to place one of those in private practice. That might have to be done at an ER or speciality hospital. BUT, it is an option.
These treatments might sound a little extreme, but pseudomonas sometimes needs extreme treatments because of it's resistance. Sometimes the oral meds just can't get it. SO then next step would be injections I would think, and lastly things like topical administration of creams into the nose, or flushes. I have never had to go that far thankfully. But, it's not seen every day either. Most of the cases I have seen eventually recovered with medications. Some had to have chronic dosing long term.
I read a report, I wish I knew where it was in the resources, but it was on a case where the cat was given an eye drop medication that was then used for daily administration into the eyes, and this in turn was absorbed through the lacrimal ducts into the sinus. That worked in that cat. I can't find the article though. Perhaps the drops could also be dripped into the nostrils, but many cats again will not tolerate that and might suffer some slight respiratory embarassment or difficultly breathing during that kind of treatment.
So, there are options though. Oral meds, injectables, creams. And if these are inconclusive, consider antifungals a last resort.
Honestly though, most of the infections I have seen were related to teeth somehow. Remember just because the teeth look ok from the gums out, doesn't mean they are ok below the gums. AN xray will sometimes show a completely different story.