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Perineal Hernia in dog, Tie-Back Surgery

Pyometra - PYO

Pyometra is an infection of the uterus (womb) that can occur commonly in adult female intact dogs (non-spayed) and rarely in adult female intact cats.  This condition is most often a life-threatening emergency, which can cause pets to become rapidly sick over hours to days.

How is a Pyometra diagnosed and treated?

  • Blood work is often done to evaluate a pet’s organ function and white blood cell count (often very high in patients with pyometra).

  • X-rays and/or ultrasound of the uterus can be taken to help determine if it is filled with fluid or pus.

  • Cytology (cell analysis) of the vaginal cells is sometimes performed to determine which phase of the heat cycle a pet is in.  

  • Emergency surgery is usually indicated to remove the pus-filled uterus as the source of infection. Removal of the ovaries is performed at the same time (spay surgery/ovariohysterectomy) to prevent future infection of any remaining uterine/cervical tissue.

  • Antibiotics are prescribed to help treat residual infection in the body.

  • Depending on the severity of illness, hospitalization for IV fluids and IV antibiotics may be recommended to return a pet to baseline or treat a life-threatening infection.

  • Rarely, pets with an open pyometra can be treated with antibiotics and hormones alone (without surgery), but there is a chance that surgery may ultimately be needed or that a future pyometra will occur in subsequent heat cycles. This is not a good option for pets that are very ill due to pyometra.

What kind of surgery is recommended for a Pyometra?

Surgical treatment for a pyometra is an ovariohysterectomy (spay surgery).  In this surgery, pets are placed under general anesthesia.  An incision is made midline over their abdomen (belly) and the uterus and ovaries are removed.  The abdomen is flushed with saline to reduce residual bacteria levels.  The body wall and skin are then closed and the pet is recovered.  Pets will often require hospitalization for one to several days after this surgery, depending on the severity of their illness and their speed of recovery.  Pets receive antibiotics and pain medications in the hospital and may be discharged with these medications to continue at home for several days.  

Can Pyometra's be prevented?

Up to 1 in 5 female intact dogs will develop pyometra in their lifetime. The only prevention for a pyometra is to spay female dogs.


Pyometra usually occurs within 2 weeks to 3 months of a heat cycle or breeding.  It can also occur in pets that are being treated with hormones, such as estrogen or progesterone. 


In pyometra, an infection occurs due to bacteria that migrate through the cervix and begin to divide inside the uterine lining.  There are two types of pyometra: open and closed.  

  • “Open pyometra”: When an infection occurs in a pet that has an open cervix, this is called an “open pyometra”.  In this type of pyometra, pus or thick red, green, yellow or brown discharge may be seen from the vagina.  Pets may show signs of illness (vomiting, lethargy, reduced appetite, increased thirst and/or urination, fever) and these signs may progress over several days to a week.  

“Closed pyometra”:Pus accumulates in the uterus behind a closed cervix and no discharge is produced outside of the body.  These pets often become sick more quickly since the bacteria and pus are trapped inside of the body. Pets with closed pyometra will often show similar signs as pets with open pyometra (vomiting, lethargy, reduced appetite, increased thirst and/or urination, fever), but they tend to progress more rapidly (over hours to 1-3 days) and will often become very sick very quickly.

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