One of the benefits of putting the medicine in the nose is that you are not treating systemically, so you aren't killing of the GI Flora. It's also easier on the kidney and liver. Since you have an adult bird that had t been exposed to new birds, a virus is less likely, and most if the chronic viruses effect them systemically so she would have other symptoms. Yeast usually starts GI then spreads but not always. Nebulization is probably the best of the best, but really the antibiotics placed into the sinus is a very practical and safe approach by an experienced veterinarian. It's much faster working and easier on the birds body for what is most likely a bacterial infection. Overuse of antibiotics definitely leads to yeast and fungal problem. Since we aren't vets and we didn't exam your bird, all we can do is share our experience. Since you saw a CAV with good recommendations and you delt comfortable with them I would trust their judgement. We all hope Fancy gets well quickly!!! I too feel blood work and fecal exams are good practice even for well parrots.
The big issue here is that she has no idea if the antibiotic her bird was given was one that will treat what is going on. That's the problem, not the Route of Administration of the medication at all..I actually use Neo-Poly Dex eye drops quite often at the Rescue in ears, the sinus passages, and actually in the Nebulizer (the Dextrose isn't great for this method, but it still works wonders)...Something a lot of people don't realize is that many medication formulations are exactly the same. For example, many antibiotics that come in both an injectable formulation, such as IM or IV formulations, and are labeled as such, are EXACTLY the same formulations as the one labeled for Oral use. They just come with different labels on their bottles, and usually the Oral formulations cost more, ridiculously. Tylosin/Tylan 50/100, Amoxicillin, Tetracycline, etc. are all like this. It's mostly a money scam by the pharmaceutical companies, to be completely honest...
****My major issue with what this Vet did, as was also wisely commented on by Noodles first, is that they did the "let's try this and see if it works" thing, or the "Just in-case" or even "I'm guessing this will work" thing...I have yet to figure out if this is just due to laziness, lack of education/training, a hesitation/fear by the Vet to want to take cultures from a bird/reptile, or even a lack of knowledge about what to look for under a microscope, but any way you look at it it's irresponsible and actually quite dangerous in a lot of cases...And it cannot be due to them wanting to save the client money, say if the client tells them they cannot afford to pay extra for lab tests, because they can at the very least use their Microscope to diagnose quite a lot of infections (as most cultures have to be sent out to a lab to be grown, but ANY and ALL Vets should be able to do a Gram-Stain, a Fecal-Float, or even just a wet-mount or direct slide of a swab they take and be able to visually identify whether they see Bacteria, Fungi, or both, and be able to use basic Microbiology/Cytology skills to at the very least narrow-down any Bacteria present to Gram - or Gram + and shape, etc., which will give them a lot of direction as to what antibiotic will at least have a shot at treating it)...And this shouldn't cost the client a penny extra, as they are not sending anything out to a lab to be tested, and they aren't using any supplies that should be charged for, they're just taking swabs/cultures, mounting them on a slide, staining them, and then looking at them under their microscope...that's it.
So that's why it's so difficult to understand why any Vet would just look at a bird, say "they probably have a sinus infection", and then just choose an antibiotic that is either very broad-spectrum, or that is used to treat the most-common cause of sinus infections in birds, when they could literally KNOW for sure what it is and what will work to treat it in about 10 minutes of extra work. And as far as a Fungal Infection goes, they absolutely can develop a secondary Fungal/Yeast infection from getting antibiotics through other routes of administration than oral,
as Yeast/Fungi is kept at-bay by healthy, normal Flora all over the body, specifically in all bodily orifices, as well as in any areas with mucous membranes that are warm and moist. Any route of administration that leads to the antibiotic reaching the blood-stream can cause secondary Yeast/Fungal infections locally, as well as systemically in totally unrelated areas...The most common example of this is how women commonly develop Vaginal yeast infections whenever they take antibiotics not just orally, but by injection, and if the antibiotic is strong enough, even topically.
Even if Gentimycin is the correct antibiotic to treat the infection that this bird has in his sinuses, it may very well cause a secondary Fungal Infection, not only throughout his sinuses, but also throughout his GI Tract, in his eyes, in his ears, and in his throat/mouth (as "Thrush" is a common side-effect of taking antibiotic eye drops, ear drops,
and nasal sprays). We often forget about Thrush, Vaginal Yeast Infections, and then also yeast/fungal infections that are topical or in the eye, ears, sinuses, etc. But they are extremely common when taking any antibiotic that reaches the bloodstream, which is pretty much all of them except most topical antibiotics that are used on the skin...
The bottom-line to this is that too many birds, reptiles, amphibians, etc. are dying because of this very issue. And they typically die because they are given medications that do not treat whatever it is that is making them sick, because no simple diagnostic testing is done and the Vets just "guess" what is wrong and what medication might treat what might be wrong. And what's worse is that a lot of the time they suffer for weeks while taking the wrong medication, and THEN they die...when a simple swab on a slide under a microscope can diagnose them properly and enable the choice of the correct medication to treat what they have...And that's just totally unacceptable in this day and age when all Veterinary offices have a compound microscope, blank slides, and a Q-tip...
