You're not doing anything wrong Hun - there's not much info for vets concerning piggie breathing problems if baytril doesn;t cure it. Many vets are only prepared to prescribe what is licensed for piggies (which isn;t much i.e. baytril). Some will use other unlicensed antibiotics (eg septrin) for infections but will stop at that. Others are prepared to try to diagnose the problem if it isn;t infection and try other medications that have proved effective on other animals. It's one of the reason why it's really worth ensuring you know of a cavy-savvy vet or at least one that is prepared to consider alternatives providing the right information can be given to them.
Fluid can occur in several different places - either actually within the lungs (pulmonary oedema) or in the chest cavity itself outside the lungs (Pleural effusion) and it may also occur in the pericaridal membrane around the heart
Causes can include, but are not limited to, infection, heart problems and trauma.
So first step is if baytril isn;t working, you could ask the vet to try another antibioitic (septrin azithromycin or doxycycline). However if the cause isn;t bacterial, the antibiotic will not help (except to prevent secondary infection occurring)
Heart problems don;t just show as a heart murmur/irregularity which is what vets tend to listen for. Muffin had laboured noisy breathing. She was initially treated with baytril for a respiratory infection but that didn;t work. Although there were no irregularities in her heart beat - we found a slightly large heart and fluid around it on X ray. I took in the information from Guinea Lynx and my vet agreed to start heart meds . We put her on fortekor (1mg/ml) and frusemide (2mg/ml) twice daily for 4 weeks. A follow-up X ray showed the chest area clear of fluid. We continued with the fortekor but not the frusemide and her breathing problems came back. She is now back on the combined medication twice daily and back to her old self.
Therefore an X ray may show where the fluid is located (and whether the heart is enlarged) and, depending upon the findings, it;s worth discussing with the vet whether frusemide (a diuretic) can be used to reduce the fluid within the lungs and help Chestnut breathe more easily. I have an older piggie Grommie who occassionally gets very wheezy becuase he has fluid in his chest/lungs. Having the central heating on doesn;t help him so I make sure there are plenty of bowls of water to increase the humidity around him (and put Vicks Vapour bath in the water). However when he gets especially rattly, the vet has said he can have a one off dose of fruseamide (up to 10mg/kg) and then maintained on 2mg/kg twice a day for a few days until he sounds better.
HTH
PM me if you want further details
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