My dog has just had surgery for acute Pyometra. She's OK now, but it was a bit scary. But the signs were not that clear when they started. It was ONLY because I was fully aware of Pyometra, and acted swiftly, that she is alive right now.
In her case, she was fine the day before....the night before...and then WHAM! Suddenly, in the morning she was lethargic, had a creamy profuse discharge, (which, by the way didn't smell bad!) -and was 'straining' as if she was trying to give birth. That particular sign was the clincher. From what could have been a mild tummy upset....it became highly suspicious. I put two and two together seeing her strain as if whelping like that, and figured that's what it was -she was contracting her womb to get something out!
Pyometra can strike suddenly like that. It can strike a really healthy dog in hours. Leave it TOO many hours, and that healthy dog could be dead.
It is a really nasty womb infection. What causes it is either: too much Progesterone hormone, or an unusual response to Progesterone. The womb fills up with fluid, and pus, and the "horns" of the Uterus swell to huge size. At this point toxins are already being released, causing fever to suddenly soar (in my dog's case her temperature was 104.5) and can overwhelm the kidneys, causing acute Kidney Failure. Another possible outcome so the vet told me is Diabetes Insipidus. Pyometra typically strikes middle-aged or older, unspayed females. It doesn't make ANY difference to the risk of developing it, if she has had puppies in the past....if she has been mated....etc. It can strike her anyway. And even though it's less likely to affect young dogs, it still can, so be careful.
The best cure is emergency spaying plus intravenous fluids (to flush the system and spare the kidneys, hopefully) -and antibiotics.
Now the secret is in being very watchful for the signs, and being VERY ready to dash to the vet/ER/ wherever. Time is of the essence here.
All I saw was a slightly "off " slightly lethargic dog who suddenly refused an extra treat, and if I looked carefully I could see her belly 'straining'. But if I'd been too busy....too preoccupied with something else....out shopping....whatever....I might not have noticed.
Pyometra is quite common. It is deadly. It's not something to "wait and see" with. It is a raging emergency.