My 6-year old unsprayed female dog was recently diagnosed with pyometra. What is it and how is it treated?

Pyometra is a condition that usually occurs in middle-aged or older female dogs or cats about six weeks prior to going into heat. In pyometra, pus fills the uterus, causing inflammation and infection. Toxins and bacteria from the accumulated pus may cross the uterine walls and leak into the bloodstream.

During each breeding cycle, the uterus swells in preparation for pregnancy. Over several breeding cycles, the tissue can become permanently enlarged and bacteria from the vagina can migrate upward and infect the uterus causing further swelling and pus. Some common symptoms are poor appetite, vomiting and drinking excessively. In an open pyometra, in which the cervix is open, some of the contents from the uterus may leak out, causing vaginal discharge. In a closed pyometra, in which the cervix is closed, there is no vaginal discharge. A closed pyometra may be more difficult to diagnose and may also be more severe because all of the toxins are being retained in the body. The treatment is the complete removal of the uterus and ovaries. Pyometra surgery is much more difficult and dangerous than a typical spay surgery, even though they both remove the uterus and ovaries. Extra precautions must be taken to ensure that the contents of the uterus do not leak out and infect other parts of the body.

Spaying (ovariohysterectomy) provides complete prevention for pyometra. It removes the organs that would be affected in a pyometra case: the uterus and ovaries. Puppies and kittens can be spayed as soon as they are fully vaccinated, usually at 5 to 6 months of age. Adult females can be spayed at any time, as long as they are in good health. Spaying not only prevents pyometra but can also prevent mammary cancer and eliminates the unpleasant odor and bloody discharge associated with female dogs in heat.

Need advice from METRO’s pet experts? Send questions to metrobeijing@chinadaily.com.cn or our Sina Weibo @chinadailymetro. Answers supplied by the International Center for Veterinary Services on (+86 10) 8456-1939.