If you have an unspayed female cat, there’s one condition worth knowing about: pyometra. Pyometra in cats is a serious infection of the uterus that causes it to fill with pus, usually following hormonal changes after a heat cycle.

 

Without prompt treatment, the infection can quickly become serious and potentially life-threatening. While pyometra is more common in older unspayed cats, it can occur in younger cats as well. Recognizing the signs of pyometra early and seeking veterinary care quickly can greatly improve your cat's chances of a full recovery.

KEY TAKEAWAYS

  • Pyometra in cats develops a pus-filled uterus, a life-threatening emergency.
  • Cat pyometra symptoms include lethargy, loss of appetite, increased thirst, and sometimes vaginal discharge.
  • The condition usually strikes unspayed cats within a few weeks of a heat cycle.
  • Treatment is almost always surgical removal of the uterus and ovaries.
  • Early intervention leads to a high survival rate, around 94% or better.

What Is Pyometra in Cats?

Pyometra is a serious, life-threatening bacterial infection of the uterus that causes it to fill with pus. It's most often caused by E. coli, Streptococcus, or Staphylococcus bacteria and it typically occurs in unspayed female cats (queens) following a heat cycle. During this post-heat phase, hormonal changes cause the uterine lining to thicken and create an environment highly susceptible to infection. Without immediate treatment, pyometra can quickly become life-threatening and lead to serious complications such as sepsis or uterine rupture.

What Are the Symptoms of Pyometra in Cats?

Signs of pyometra in cats can be subtle at first. Watch out for:

  • Lethargy and depression
  • Loss of appetite
  • Increased thirst and urination (less common in cats than dogs)
  • Vomiting or diarrhea
  • A swollen, tender abdomen (especially in closed pyometra in cats)
  • Vaginal discharge (in open pyometra in cats)

 

The symptoms can also differ depending on whether your cat has open or closed pyometra.

  • Open pyometra in cats: Occurs when the cervix remains open, allowing pus or blood-tinged discharge to drain from the uterus. You may notice discharge around your cat’s tail, bedding, or resting areas,
  • Closed pyometra in cats: Occurs when the cervix is closed and the infected material cannot drain. The uterus can become enlarged, and affected cats may become seriously ill very quickly. 

What Are the Causes of Pyometra in Cats?

Pyometra develops from a combination of hormonal changes and bacterial infection. After a heat cycle, progesterone causes the uterine lining to thicken, which can create an environment where bacteria can easily multiply. Bacteria may also enter the uterus when the cervix opens during heat. The risk generally increases with age and repeated heat cycles, which is why pyometra is more commonly seen in older, unspayed cats over 5 to 7 years old.

How Veterinarians Diagnose Pyometra in Cats

Your veterinarian will usually consider your cat’s recent heat cycles, perform a physical examination, and may recommend blood or urine tests to assess your cat’s health. Imaging tests such as an ultrasound or X-ray can also help identify an enlarged, fluid-filled uterus and distinguish pyometra from other conditions such as pregnancy. If your unspayed cat suddenly becomes unwell, especially after a recent heat cycle, it’s best to have her checked as soon as possible because symptoms can be subtle. 

How to Treat Pyometra in Cats

Pyometra cat treatment requires urgent veterinary treatment. An ovariohysterectomy (also known as spaying) is done to remove the infected uterus and ovaries being the preferred treatment for most cats. If a cat is seriously ill, she may first need IV fluids and antibiotics to help stabilize her before surgery. In selected cases, medical treatment using prostaglandins may be considered to help the uterus contract and expel the infected fluid.

How to Prevent Pyometra in Cats

The most effective way to prevent is to spay your cat. Spaying removes the ovaries and uterus, which prevents the hormonal and uterine changes that allow pyometra to develop. If your cat is intact, watch closely for signs after each heat cycle and never delay a vet visit if she seems unwell.

Don't Wait, Your Cat Is Counting on You

Pyometra is a serious condition, but knowing what to look out for can help you act quickly when it matters most. If your cat is unspayed, talk to your veterinarian about the right time to have her spayed, and keep an eye out for any unusual changes after a heat cycle. If something doesn’t seem right, it’s always better to have her checked sooner rather than later.

 

Want to learn more about keeping your cat happy and healthy? Explore the WHISKAS® blog for more helpful tips on cat health, nutrition, and everyday care.

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