What is Pyometra?
Pyometra is a serious disease of unspeyed females. It is most common in older (6years+) bitches but can also occur in female cats (queens),rabbits, ferrets, rats and guinea pigs. It can occur in younger animals, although this is less common.
Pyometra literally means pus in the womb (uterus). It is the result of abnormal hormonal levels or abnormal response of the uterine lining (endometrium) to hormone (progesterone) levels, typically 6-8 weeks after heat. Cystic Endometrial Hyperplasia may occur and bacteria (often E.coli) get through the cervix and infect the thickened uterine lining. The high progesterone levels continue to close the cervix and reduce uterine contractility, allowing for the infection to establish and pus to build up.
Bitches who have had mismating estradiol shots are at increased risk of developing pyometra.
A pyometra may be open (where the cervix is not entirely closed) and pus will discharge through the vulva. These cases are generally not so critical and are easier to diagnose and treat.
A closed pyometra (where the cervix does not allow any escape of pus through the cervix) is a much more serious situation as the patient tends to become septicaemic very quickly and is at risk of uterine rupture and peritonitis.
What are the Symptoms?
The most obvious symptom of an open pyometra is discharge of pus from the vulva in a female which has been recently in heat.
The symptoms of a closed pyometra are less obvious. In both cases symptoms can include vomiting, lack of appetite, fever, depression, increased thirst and urination. Sometimes abdominal enlargement (a bloated looking tummy) may be seen, and occasionally owners may have thought there was a pregnancy.
Often your vet will need to do blood tests, and maybe x-rays or ultrasound scans to make a diagnosis.
What is the Treatment?
If the bitch (or other female animal) is not a valuable breeding animal, the best treatment is surgical removal of the uterus and ovaries as soon as she has been stabilized with intravenous fluids and antibiotics. In closed pyometras where the bitch is in septic shock, or there is peritonitis from uterine rupture, the surgery is much higher risk with the possibility of severe complications or death.
In some valuable breeding animals a treatment involving hospitalization and hormone injections may be tried to evacuate the pus from the uterus. This is however frequently unsuccessful and may result in the need for surgical removal of ovaries and uterus anyway.
What is the best Prevention?
The only way to be sure your pet won’t develop pyometra is to have her surgically neutered. If you are not intending to breed from her this should be done as soon as possible; ideally before her first heat. This also greatly reduces the chance of her developing breast cancer later in life.
