Dear Melissa: You might want to consider asking Growler what she can tell you about her puzzling condition. Just as we humans are able to tell our doctors what we are feeling in our bodies, I have found it very helpful when faced with a medical problem with one of my cats that is not obviously diagnosable, to ask my cats with the help of an AC and that has more than once saved me money (for unnecessary diaganostics) and a lot of worry and wondering. Feedback from the cat can help to narrow the focus for a vet's diagnosis and even tell you exactly what the problem is.
Sincerly, Sally in San Jose
