Pyometra: A Dangerous Infection in Dogs and Cats
By Lakeshore Road Animal Hospital

If you have an unspayed female dog or cat at home, there’s an important condition you should be aware of—pyometra. It’s a serious, potentially life-threatening infection that we see all too often, and it can come on quickly.

What is Pyometra?

Pyometra is an infection of the uterus that happens in unspayed females. It occurs when hormonal changes during the heat cycle cause the uterine lining to thicken and become a breeding ground for bacteria. Over time, pus builds up in the uterus, causing a dangerous infection.

Both dogs and cats can develop pyometra, and while it's more commonly diagnosed in middle-aged or older pets, it can happen after any heat cycle—even in younger animals.

Signs to Watch For

Symptoms can vary, but here are some of the most common ones to look out for:

• Lethargy (low energy, hiding, or “not themselves”)
• Decreased appetite
• Vomiting or diarrhea
• Increased thirst and urination
• Vaginal discharge (pus-like, bloody, or cloudy)
• Swollen or painful abdomen
• Fever

In some cases (especially in cats), there may be no obvious discharge, which makes it even harder to catch early. If your pet has recently been in heat and isn’t feeling well, don’t wait—this could be a medical emergency.

Why It’s So Serious

If left untreated, pyometra can cause the uterus to rupture, leading to a body-wide infection (sepsis), organ failure, or even death. Most cases require emergency surgery to remove the infected uterus and ovaries—similar to a spay procedure, but much riskier and more urgent.

The Best Treatment is Prevention

The most effective way to protect your dog or cat from pyometra is to spay them before they start going into heat. Spaying not only eliminates the risk of pyometra but also reduces the chances of mammary (breast) tumors and helps prevent unwanted litters.

When to Contact Us

If you notice any of the signs listed above, or if your unspayed pet just isn’t acting like herself after a heat cycle, don’t wait. Call Lakeshore Road Animal Hospital right away. Early action can save your pet’s life.

We’re here to answer your questions, provide expert care, and help you make the best health decisions for your furry family members.