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Pyometra: An Avoidable Emergency

by Dr. Karen, DVM

The term "pyometra" (often shortened to "pyo"), refers to a condition where an infection occurs in the uterus of a female dog or cat. This results in an accumulation of pus within the uterus. This condition can occur any time after a female's first estrous (heat) cycle, but is commonly seen in up to 25% of intact (unspayed) middle-aged and older dogs. In cats, the incidence tends to occur much younger, and your kitty may not show apparent signs of being ill until the infection is far advanced. For both dogs and cats, this condition can quickly become life-threatening.

There are two types of pyometras which occur- closed and open:

Open Pyometra- this occurs when the cervix is open, allowing some of the pus to drain out through the vaginal opening. An owner may notice a creamy to bloody discharge, often with a foul odor. The pet may excessively lick the vulva, and may or may not yet show signs of not feeling well.

Closed Pyometra- this occurs when the cervix is closed. There is no vaginal discharge, and your pet will likely be acting sick. Closed pyometras will cause your pet's health to deteriorate quickly as the pus builds up in the ever-enlarging uterus. The uterus can eventually rupture, causing acute peritonitis and death. An owner may notice their pet is lethargic, has increased vomiting and urination, a decreased appetite, and may experience vomiting and diarrhea. In extreme cases, she will even exhibit abdominal enlargement.

If your pet is an intact female, any subtle signs of illness should be evaluated by your veterinarian as soon as possible. Proper diagnostics will include a complete history and physical examination, blood tests, urinalysis, vaginal cytology, X-rays, and ideally an ultrasound of the uterus. If the diagnostic testing confirms a pyometra, your veterinarian will advise the best treatment options for your pet.


A. Surgical removal of the uterus and ovaries- this is the best treatment for most patients, as it will remove the infection and source of any further recurrences. The patient must be medically stabilized first at your primary care veterinary hospital, as this is a higher-risk surgery, but can save your pet's life! Because it involves removing and infected uterus (compared to a normal spay with a sterile uterus), there are many extra steps to the surgical procedure. There are also extra medications flushing of the abdomen with sterile solutions, and IV fluids given. Therefore, this procedure is much more expensive than a normal spay surgery.

B. Medical treatment- this may or may not be successful and should only be considered for valuable breeding animals. The cost will often exceed that of surgical treatment.

Neither surgical or medical treatment for pyometra can be guaranteed. Success is a patient living through the treatment, and the success rate is higher if the diagnosis happens in the early stages.


Set-up your pet's spay surgery appointment when she is receiving her four-month old vaccination boosters. This way, you will avoid any chance of a future pyometra occuring. Your puppy or kitten will rebound from surgery more quickly than a mature pet. If your pet is older, it is still far safer to have her spayed than deal with an avoidable, life-threatening emergency.



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