I answered a call a couple of weeks ago where the caller asked me what pyometra was and if she should be concerned. It reminds me of another caller who asked what I thought about the whites of the eyes turning yellow. There are times when you need to know that red flags are flapping in the wind and you should take your dog (in the first case) or yourself (in the second case) to the respective doctors.
Pyometra is not something you sit back and wait to see what will happen next. This is a bacterial infection or abscess of the uterus and if it is left untreated, it can kill your pet. It is most commonly found in female canines over the age of five or six years. It is believed to be caused by a hormonal imbalance.
The disease appears one to 12 weeks after the animal goes out of heat. There are a number of symptoms and the dog may exhibit one or several or just slowing down, which does not alert the owner right away. These symptoms include anorexia or loss of appetite, depression, lethargy, increased water consumption, frequent urination, abdominal enlargement, and a low grade fever (or, as the textbook says, a normal even sub-normal temperature).