I am very late responding to this, but just learned of it. I'm very sorry you lost Milo. With your other rats, if you experience symptoms like that again, it could very well be an inner ear infection. I lost a few rats this way thinking it was PT, and finally did a necropsy on one and it wasn't a tumour. That's when I started being aggressive with amoxicillin in these circumstances. Along with pred or dex. Baytril doesn't really do anything for an inner ear infection. However, you can give baytril and amoxicillin together, so you're not messing up your medical regime for myco, for instance.
BTW, Metacam is bad for rats and should be used only short-term for a few days - five days maximum. And you have to wait 48 hours between using a NSAID and a steroid in a rat or guinea pig. A week if it is a dog or cat. (Metacam is very bad for cats too, but is drug of choice for guinea pigs).
You have to give at least 24 hours between pred or dex as well, btw.
If you have a rat that is experiencing a myco attack, Dex is a better option than pred because they've recently learned that Dex just doesn't act as a steroid, it also actively attacks myco.
With rats, if they have active myco, the recommended course of action is to start them on baytril & doxy at the most mild of symptoms, including a grunt, which we shouldn't hear, and keep them on baytril & doxy long term as in a minimum of 6 weeks and for older rats, for the rest of their lives.
and with old rats where there is noisy breathing, keep them on steroids long term too. Low dose, or do pulse therapy with steroids. This site
http://ratguide.com/
has some very good medical advice with treating myco and other rats issues. A vet who works with a rat rescue help them do the medical portion of the site. He has done hundreds of necropsies on rats. The rescue is operated by a vet tech.
http://ratguide.com/
The woman who runs the site isn't as big on amoxicillin or bactrim as I am with regard to secondary infections, but I have had a lot of success lately with intermitent use of bactrim or amoxicillin in
conjunction with doxy/baytril. Secondary infections are common in rats too. But keeping Myco in check with more aggressive and longer term use of baytril and doxy is also helpful with helping keep secondary infections at bay. But adding a secondary infection drug like amox or bactrim has proven to be very effective with my previous groups of rats and with really sick rescue rats.
My current & healthy group - they are turning two in a few weeks - I've noticed that when I take them off min dose baytril & doxy now, the symptoms start up again within a few weeks. So... I've made the decision to keep them on it for the rest of their lives to prevent myco from doing its dirty work behind the scenes. Even when rats are relatively symptom free, myco can still be very active and causing scar tissue etc. The site has good information regarding exactly HOW myco damages the lungs. Frightening, actually.
After communicating with Lyndsey from the site last Sept, I followed their advice and this group remains in good shape. It will be interesting to see what happens six or nine months down the road. I think if I follow through with doxy/batril at this point, I might be lucky and get to avoid steroids all together since this group has never been sick, other than showing extremely mild symptoms a couple of times.
I used pred for two months on a old rescue rat and it kept him comfortable and active until the last day. Then long term use of pred caught up to him, along with everything else, but he would have had to have been euthanized many weeks earlier if not for pred.
He and his brother arrived in bad shape, and the first time I weaned one brother off pred because he was symptom-free, his symptoms exploded and I had to euthanize him a day later. Putting him back on pred didn't stop the progression at that point. The vet who works with the rescue said that steroids are an extremely important part of keeping a rat comfortable and improving quality of life. He feels strongly that a lot of vets are not using them enough, or long enough. There are side effects with steroids, of course, but in most instances, the rat would have been PTS earlier without use of them.
http://ratguide.com/