A Primer On Pyometra

Written and reviewed by John A. Bukowski, DVM, MPH, PhD
and Susan E. Aiello, DVM, ELS 

Pyometra is a bacterial infection in the uterus of dogs. 

It is a serious and frequently life threatening condition that requires prompt treatment.

The risk of Pyometra is highest in dogs that have not been spayed or that are on any type of hormone-based therapy. Pyometra may be seen in young to middle-aged dogs, but it is most common in older dogs. It usually develops about 1-2 months after an estrus (or heat) cycle.

The uterine wall becomes thickened and engorged after many years of heat cycles, making it more prone to bacterial infection from bacteria that are normally present in the vagina.

In an open pyometra, the cervix is open, and the dog will have a vaginal discharge.

In a closed pyometra, the cervix is closed, and there is no vaginal discharge.

Other signs in both types of pyometra can include fever, increased water drinking and urination, lethargy, lack of appetite, vomiting, and diarrhea.

Dogs can have only mild symptoms or be extremely ill. 

Signs are often more severe in closed pyometra, because the closed cervix does not allow the vaginal discharge, which contains bacteria and pus, to drain from the body.

Diagnostic evaluation includes blood tests, x-rays, and sometimes ultrasound. The preferred treatment is surgical removal of the uterus and ovaries, ie, a spay or ovariohysterectomy.

Dogs diagnosed before the signs become serious are very good candidates for surgery. 

Dogs that are already quite ill are at greater risk, and intravenous fluids, antibiotics, and general supportive care are also necessary. Medical management with prostaglandins, which open the cervix and contract the uterus to expel bacteria and pus, is a controversial and sometimes dangerous treatment. In addition, pyometra often recurs with medical management.


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