To chime in - 1) absolutely it sounds like a UTI, leaking is one of the first symptoms, along with a reduced appetite and general 'blahs' Fanconi dogs' kidneys can and will 'wall off' infections (loculate), so a urinalysis will frequently not show an infection. Most of us go by symptoms, although some people have had success with cultures. However, at the first indication of a problem, if you can, get the vet to put him on a 3 week course of antibiotic - Clavamox or Baytril. If the vet refuses to take your word for it, I'd consider getting a new vet. Repeated untreated UTIs do permanent damage to the kidneys.
- I second the idea that you should join the Fanconi list. There is a wealth of experience and knowledge there and phenomenal support. Everyone on the list has or has had to live with the disease, and almost any problem you can think of, people will have constructive, proven ideas as to handling it. You're never alone! And yes, if the time comes when you have to make that choice, believe me, we all know how hard it is.