Pyometra is a potentially life-threatening condition that most frequently affects older, unspayed female pets and is a common reproductive emergency seen in veterinary hospitals. Our Urgent Pet Care Omaha team wants to provide information about this dangerous condition and explain how you can protect your four-legged family member.

What causes pet pyometra?

An unspayed female pet’s hormones fluctuate during each heat cycle, causing the uterine tissue to thicken and engorge in preparation for a potential pregnancy. As the pet ages, this tissue thickening can become persistent, resulting in a condition called cystic endometrial hyperplasia. These changes predispose the uterus to infection and decrease the organ’s infection-fighting ability. The cervix usually remains tightly closed, protecting the uterus from infection, but during a heat cycle, the cervix relaxes to allow sperm to enter the uterus. During this time, bacteria from the vagina can easily enter the uterus. Typically, the uterine environment prevents bacterial survival, but when the uterine tissue is abnormal, conditions are ideal for bacterial growth. 

What are pet pyometra signs?

Pyometra is most common in middle-aged and older unspayed female pets, and they are most at risk one to two months after a heat cycle. Signs depend on whether the cervix remains open or closes. 

  • Open pyometra signs — Most commonly, the pet’s cervix remains open, and vaginal discharge is noticeable. Other signs may include fever, lethargy, lack of appetite, and depression.
  • Closed pyometra signs — In cases where the pet’s cervix closes, the infection accumulates in the uterus, releasing toxins that are absorbed into the bloodstream. The pets tends to be severely ill, and signs include lack of appetite, depression, vomiting, diarrhea, distended abdomen, and increased thirst. 

Affected cats typically don’t exhibit signs until their condition is advanced. While they may have vaginal discharge, many cats are fastidious and clean the discharge before their owners can notice, delaying diagnosis and treatment.

How is pet pyometra diagnosed?

Pyometra generally is considered when an unspayed female pet exhibits lethargy, lack of appetite, or depression. Specific diagnostics include:

  • History — Our veterinary team will ask questions to determine when your pet’s last heat cycle occurred and when her signs first appeared.
  • Physical examination — We will perform a thorough physical examination, assessing your pet’s temperature, checking for vaginal discharge, and palpating your pet’s abdomen. 
  • Blood work — Our veterinary team will perform a complete blood count (CBC) and biochemistry profile. Blood work in affected pets typically demonstrates widespread infection.
  • X-rays — In pets affected by closed pyometra, abdominal X-rays will show an enlarged uterus. 
  • Ultrasound — Our veterinary team may perform an ultrasound to evaluate the uterine wall and assess fluid accumulation inside the uterus.
  • Vaginal cytology and culture — We may take a vaginal swab sample to determine the causative pathogen.

How is pet pyometra treated?

Pyometra is a veterinary emergency that requires immediate intervention to prevent uncontrollable infection and death. Once the pet’s condition is stabilized, an ovariohysterectomy (i.e., spay) is the treatment of choice to remove the infected uterus and ovaries. The surgery is more complicated than a traditional spay because the pet’s condition is compromised, and care must be taken to prevent the abdominal cavity from becoming infected. Antibiotics are usually necessary for one to two weeks after surgery, and most pets recover well. 

What if my pet is a valuable breeding animal?

In some cases, medical treatment is an option to address pyometra, but this approach carries risks. Hormones called prostaglandins can be administered to lower the progesterone blood levels, which relaxes and opens the cervix, causing the uterus to contract and expel the infection. Drawbacks to this treatment option include:

  • Delayed improvement — Clinical improvement takes at least 48 hours, and severely ill pets who need life-saving treatment are not candidates for this treatment.
  • Side effects — Prostaglandins cause side effects, including vomiting, restlessness, excessive salivation, and abdominal pain, which can last for several hours after administration.
  • Uterine contraction — Prostaglandins cause uterine contraction, which can cause the uterus to rupture and infect the abdominal cavity. This is most likely to occur if the cervix is closed.
  • Recurrence — Pyometra recurrence is likely.

What is stump pyometra?

After a pet is spayed, a small uterine stump typically remains in the abdomen where the tract was ligated. If female hormones are circulating, infection can develop in this stump. Factors that can lead to a stump pyometra include:

  • Ovarian remnant — In some cases, a small, potentially microscopic, ovarian remnant is left behind when a pet is spayed.
  • Human products — Many estrogen-containing human products are used topically, providing potential exposure to pets when they come in contact with their owners. 

Signs are similar to a regular pyometra, and treatment involves surgically removing the infected stump and determining and removing the hormone source.

How is pet pyometra prevented?

The best way to prevent pyometra is to have your pet spayed. This procedure removes the hormonal stimulation that causes heat cycles and the uterine changes that allow pyometra to occur. Having your pet spayed when they are young and healthy is considerably safer than performing the procedure when they are affected by pyometra. Your family veterinarian can determine if an ovariohysterectomy is appropriate for your pet and decide the best timing for the procedure.

Pyometra is a dangerous condition, and spaying your pet is the best way to protect them from this potentially life-threatening condition. If your pet is exhibiting signs that may indicate pyometra, contact our Urgent Pet Care Omaha team so we can ensure they get the care they need.