Posted on October 18, 2016


Pyometra is a bacterial infection of the uterus that can affect many species of animals. Here in My Family Vet, most of the afflicted cases seen are dogs, cats, rabbits and hamsters. Since pyometra is the infection of the uterus, only female animals would be at risk for this condition.

Through lab tests and studies, pyometra is found to be associated with bacteria, mainly Escherichia Coli, Staphylococcus, Streptococcus, Klebsiella, Pasteurella, Pseudomonas, and Proteus species that are commonly found the vagina canal. When the female goes into a heat cycle, its cervix relaxes and opens to allow sperm to enter. However, this also permits the aforementioned bacteria to enter the womb effectively infecting it and causing an accumulation of pus. Diagnosis would usually involve a Complete Blood Count (CBC) test in order to detect the level of white blood cells. High level of WBC indicates infection in the body and further tests such as ultrasound have to be performed for a proper diagnosis.

There are two types of pyometra: closed pyometra and opened pyometra.

Closed pyometra occurs when the cervix is closed, causing obstruction to the natural drainage of accumulated pus from the uterus, which normally exits the body via the vagina. This obstruction would cause an unnatural swelling and distension of the uterus, causing the animal to have a pregnant appearance. This would raise alarm bells if the animal has obviously not mated before. Closed pyometra carries possible complications such as a risk of the uterus rupturing and the spillage of pus into the abdomen, causing septic peritonitis. This condition is life-threatening and may be fatal. Due to the inability of drainage of pus, closed pyometra usually goes undetected until the abdomen starts to show obvious signs of swelling. Animals may also show clinical signs such as lethargy, inappetance, frequent urination, vomiting and diarrhoea, one or two months after heat.

Opened pyometra refers to when the cervix is opened, allowing the drainage of pus out through the vagina. Abnormal vaginal discharge or pus may be seen under the tail, urogenital area or places that the female had laid on. Opened pyometra often do not cause a swollen abdomen in the animals. However, a very sick female dog recently in heat and has an increase of water intake, should be suspected for pyometra.

Most common treatment for pyometra is an ovariohysterectomy or spay surgery, to essentially remove the infected uterine horns and uterus. Pyometra surgery is usually more complicated than normal spays as one wrong move can rupture the uterus causing septic peritonitis and would require more time to complete as compared to the latter. Antibiotic treatment would also be prescribed post-surgery.

The best prevention from pyometra is to have your pet spayed when she is of age. Any age after its first heat effectively predisposes it to uterine infections.