Diabetic cats' insulin requirements can dramatically increase when they have a concurrent illness. Things to rule out are: urinary tract infections (including pyelonephritis), chronic pancreatitis, hyperadrenocorticism (Cushing's), acromegaly (increased production of growth hormone), dental disease, heart disease, and different types of cancer.
So I brought him to the hospital where I was working, performed full-body radiographs: normal. Full CBC, chemistry, T4, urine cortisol-creatinine ratio, feline PLi, urinalysis, and urine culture - all perfectly normal. Hmm....
There was not a clue as to what was going on. While a little frustrated, I knew there was a strong possibility there was still something wrong with Isaac. When I returned to Toronto, I scheduled an ultrasound for him. The ultrasound showed mildly enlarged kidneys, consistent with pyelonephritis (I've already posted twice on this disease). Interestingly, and frustratingly, his previous urinalysis was completely normal - crystal clear - and his culture was negative; not a hint of an infection.
With chronic disease, though, this is still possible and therefore not a complete mystery.
I started Isaac on a 6-8 week course of antibiotics and so far, he's doing great.
Had I not performed the ultrasound, he would likely have deteriorated.
What are the lessons here? 1) To understand that tests are not always diagnostic - of course they can be - and that normal test results do not necessarily ruled out everything.
2) In many cases, further work-ups are necessary. After preliminary tests, this often (but not always) means imaging, such as x-radiography, ultrasound, MRI (magnetic resonance imaging) or CT (computed tomography).
3) Sometimes, even specialists (in medicine, too!), cannot achieve diagnoses - there are true mystery illnesses.
4) Follow your suspicions: in this case, there was some, but not overwhelming, evidence that Isaac was sick. I was most probably right.
Isaac's diagnosis of pyelonephritis is strongly suspected, but is still not confirmed. I am now both the client and the veterinarian, and will just have to be patient for now....
Will Isaac have to go back?
