I first saw her, S, for drinking more water. She was a 9 year old Chow crossbreed dog. She had never been spayed, but otherwise was kept well by a young man without too much money to spare. After careful interrogation, I determined that there was really nothing at all wrong with her other than she had quadrupled her water intake in the past week or so.
As any good new grad would, I looked in my brain for the most obvious things. An older intact female who was at the very least PD (polydypsic) - obviously it was a pyometra, or an infected pus-filled uterus. Other options for polydypsia included kidney disease, urinary tract infection and kidney disease. X-rays at our clinic are $150, a CBC and chemistry profile is $110, and a urinalysis plus culture is about $120. Due to the financial constraints of this situation, I had to go with the most likely causes of disease. She was acting totally normally, and her temperature was normal. She had no pain in her abdomen, no vaginal discharge and I had no reason other than instinct to order abdominal radiographs.
Her urinalysis was normal, although her specific gravity was a little lower than I would have hoped. Her urine culture was negative. I did manage to convince her owner to run bloodwork when she was just not acting well a couple of days later. Because I was still curious about pyometra, I did a vaginal swab (negative) and an abdominal tap (negative). The bloodwork came back with a mild mature neutrophilia, a mild non-regenerative anemia (anemia of chronic disease), and a completely normal profile.
I didn't treat S with anything at that time. I explained the symptoms of pyometra as a surgical emergency, gave him directions to the e-clinic and sent him on his way. I didn't hear back from him for almost a month.
She appeared back on my schedule about a month later, unexpectedly. The appointment book said that she was not eating and that she had lost some weight. When she came in, I immediately noticed a couple of things. First, she had obviously lost a significant amount of weight, about 10 pounds. Second, she smelled awful! I lifted her tail to take her temperature, and asked if she had been having any diarrhea. Her hind end was coated in fetid material. Her owner denied any abnormal stools.
I pretty much didn't give the owner a choice at this point, we were going to do some x-rays (the last thing on my original 'want list'). We took her in the back and gave her a butt bath, and clipped some of the matted fur. X-rays were pretty clear - a grossly distended uterus. I again did an abdominal tap - this time easily acquiring 3cc of bloody purulent fluid. It then clicked on what the "diarrhea" was - it was pus, resulting from an open pyometra.
An open pyo was definately preferred, as it was about 5pm and the last thing I wanted was emergency surgery. I gave him the estimate and prepped her by giving a shot of antibiotics and a liter of fluids subcutaneously. He was scheduled the next morning to drop her off for surgery.
Surgery, like almost nothing else in this case, went textbook perfect. I had a vet student with me, and she had fun scrubbing in and helping me out. She was bright, alert and eating the next morning. More than she'd eaten in a long time. She went home that afternoon on antibiotics.
A week later her owner was pleased to report that she was bright, alert and eating normally again. Success! Score one for intuition. :)