Just leaving a dog is a cage was one of my BIG pet peeves. There is no excuse, if that is what happened. Sometimes, dogs do hold it, but with high urine output due to Cushing's, UTI or renal disease, most take the advantage of any opportunity to relieve themselves.
Contrary to personal experiences related here, potentiated sulfa drugs are one of the best choices for UTIs. They have a very low incidence of side effects and are remarkably effective in treating almost all of them. As with all drugs, the potential for side effects are always present, but these are situations that the vet takes into consideration evaluating each individual's health conditions and issues.
Cushing's is a pretty common disease and there are a few medication available for treatment now days. Lysodren was the only one available years ago and is still a good drug, but has some potential side effects the others don't seem to have as much.
Here's hoping that this is a situation that can successfully treated and your little one gets back to normal.
Have a safe trip "back home to Indiana."
Doug, DVM