Pyometra is a life-threatening infection within the uterus. Most commonly seen in female animals over the age of six, pyometra is caused by repeated exposure of the uterus to the hormones of the normal reproductive cycle (when pregnancy does not occur), which stimulate glands in the inner uterus wall. These glands produce increased fluid that accumulates in the uterus and this becomes an ideal environment for bacterial growth.
In dogs we see pyometra 1 to 12 weeks after they have been in season. In cats pyometra is a lot less common and the timing can be a lot more variable. It is possible (though uncommon) for pyometra to develop in the very small end of the uterus remaining in place after a spey operation. Generally, however, desexing will prevent pyometra infections.
SEVERITY: Life threatening. Requires prompt treatment.
Pyometra can be open or closed, meaning the cervix is either open or closed. If it is open, there is usually a visible vaginal discharge of pus that may be bloody or blood tinged.
If the cervix is closed there is no drainage of the infection and the animal will often become much sicker, much faster. This is much more difficult to see and diagnose as there is no discharge. Pets with pyometra will go off their food, become lethargic, drink a lot, urinate a lot, and possibly start to vomit.
If there is a vaginal discharge and a good history, diagnosing open pyometra may be relatively easy after a clinical examination. Closed pyometra can be more challenging. It is important for us to rule out pregnancy. Sometimes radiographs are required, and a blood test is also important to confirm the diagnosis and assess kidney function.
Treatment must be prompt if we are to save your pet’s life. The treatment of choice is intravenous fluids, antibiotics, and to anaethetise the patient and remove the infected uterus surgically. As there is no further need for the animal to cycle following surgery, ovaries are also removed, as is done in a normal spey operation.
Recovery after surgery is usually reasonably rapid. A 1 to 3 day stay in hospital is usually all that is required, after which care can be continued at home with oral antibiotics, close monitoring, and some revisits to the hospital.