Pulmonary edema

My cat was rescued from a week old and born without, does not have any vaccine, but she has been dewormed in order. Now is 1 year with 2 months old, was healthy and sterilized at 6 months but she began to present respiratory difficulty 4 weeks ago, X-ray revealed pulmonary edema and was treated with furosemide, ceftriaxone and dexamethasone for 4 days, she improved and relapsed, the clinical diagnosis is heart failure but there is no improvement with the treatment. Any idea for diagnosis?

Hello!  I just wanted to clarify before answering this one; What was your cat born without?

Hello!  I'm sorry to hear that your cat is poorly.  There is part of your post that I didn't understand.  You said that your cat was born without something, but I couldn't work out what.  I then realised that perhaps you meant to say that the kitten was born outside (outdoors) i.e. comes from the feral population.   You say that this youngster has been diagnosed with heart failure, and I wonder whether this is a firm (definite) diagnosis?  If heart failure occurred in such a young cat, perhaps there were congenital heart problems (i.e. the kitten was born with an abnormal heart) or bacterial endocarditis (where a bacterial infection changes the valves of the heart, altering the blood flow).  A heavy parasite burden may be another possibility (are there parasites that may cause this in your part of the world?)  Your vet has seen the x-rays so should have a much better idea than me;  I am simply guessing.  Good questions to get more information from your vet include, What abnormalities can they see on the x-ray?  What processes do they think caused them?  And - vitally - what sort of prognosis do they expect?  It could be that they need to refer you to a specialist to answer this question, or - if they do not have a specialist available - they could refer the radiographs to a specialist, in order to get the best information they can.  I hope that you manage to get a good answer to your question and appropriate treatment for your little one.