Vet Blog

Case Study: Pyometra

July 28, 2020

WARNING: Detailed discussion of surgery. Read on with caution.

Have you ever heard of a "pyometra?"

If your answer is "no," you're not alone. In fact, I took a poll of 12 non-doctor staff members currently employed at our hospital, and only 1 knew what a pyometra was before working in veterinary medicine. Just ONE. And most of us grew up with animals.

So what is a pyometra?? It's when the uterus of a female dog or cat becomes infected with bacteria and fills with pus. Yep, it's as yucky as it sounds. The dangerous thing about this is that the uterine wall can become weak in spots and bacteria and toxins can leak through into the abdomen and cause life-threatening complications. If it is left untreated, the pet will not survive.

How can a pet develop a pyometra? It starts when an intact (has not been spayed) female has a heat cycle and bacteria from the vagina enter the previously sterile uterus, infecting the uterine wall. The bacteria multiply and the uterus fills with white blood cells (trying to fight off the infection) along with other microorganisms, or what we call "pus." The more heat cycles an animal has had, the more likely they are to get this kind of infection, which is why you typically see it in older dogs.

Today Dr. Nichols did a surgical pyometra removal on an adorable pug and her owner was kind enough to let us tell her story.


Name: "May"
Age: 8 years old
Breed: Pug
Color: Black
Weight: 21.8 (before surgery)
Temperature: 100.8 (average canine temp is 100 - 102.5)

Initially Presented For:

  • inability to open eyes
  • started acting strange 2 days ago
  • vomited 2 days ago
  • not eating
  • sleeping all day
  • belly is more red than usual
  • heat cycle lasted 4 weeks instead of 2 and ended 1 month ago
  • drinking more water than usual

Diagnostic Testing

  • physical exam by a doctor
  • Complete Blood Count (CBC) and Chemistry Panel (bloodwork)
  • X-rays

The Doctor's Findings

  • the lower abdomen felt tense and full when the doctor palpated it
  • the CBC showed leukocytosis, which is a high white blood cell count, and other increased values, indicating a major infection
  • the chemistry panel showed increased values as well
  • X-rays showed a distended uterus that encompassed the lower abdomen


  • Pyometra

Recommended Treatment

  • emergency surgical removal of the uterus and ovaries
  • IV fluids
  • antibiotics
  • pain medication

So that's what brought May to us today. Removing a pyometra is the same concept as a routine ovariohysterectomy (spay), but it is so much more complicated and dangerous. To begin with, you're performing surgery on a sick animal. Secondly, when the uterus is removed, it CANNOT be ruptured. If the contents spill into the body it can cause a whole new set of problems. It's imperative that the patient does not have any excess bleeding. Ultimately, the pet is in a life-threatening situation. The doctor's goal is always to keep the pet under anesthesia for as little time as possible. But this procedure requires more time. The doctor has to work quickly while still being patient and thorough.

Remember how May only weighed 21.8 pounds? Her uterus by itself weighed just under 1 pound! A typical uterus for a dog her size weighs only a few ounces. It's no wonder she didn't feel well. And this infection came on fairly quickly - if you'll recall, her heat cycle ended a month ago, which is likely when she developed the infection. She started showing outward symptoms only 2 days ago. (Dogs and cats are great at hiding their pain.) Her parents got her in at just the right time, and although it is a dangerous procedure, having the emergency surgery done first thing the next morning saved her life.

May's dad was gracious enough to let me ask him some questions. He, too, had never heard of a pyometra until the doctor informed him of the diagnosis, so he was happy to help educate other pet owners about this potential danger.

1. Why did you decide not to have May spayed?

"We always had the intention of breeding her at least once. I never felt it was my right to take that away from her and while we did come across several studs, they had already been neutered or were not a suitable match for her."

2. Did you know there was any risk to keeping her intact without having her bred?

"We never had all the facts. While I had always heard people saying that it's better to have your dogs spayed no one ever really gave any reasons as to why."

3. How did you know something was wrong and that she needed to see a doctor?

"After 8 years of living with your pup, you get to know them, how they behave, what they like and don't like, and also when they are not behaving how they normally would. So when she started acting strange I immediately knew that something wasn't right."

4. How did you feel when you were told her diagnosis?

"My first reaction was disbelief, she is still young, and as mentioned before she never really showed any signs of such illness. After the initial impression, it was clear to us that we had to do what was right by her even if it meant taking away from her the possibility of breeding."

5. Knowing what you do now, would you have done anything differently when she was younger?

"I like to think that I would have still given her the opportunity to breed but knowing what I know now I would have taken a decision on the matter years earlier and not allowed for it to become a high-risk situation like the one we just had to go through. Being informed is key to this situation and sadly we had to live through it to know it and understand it but glad we can now say that we are prepared for any future pets."

As you can see, many people have good intentions for not spaying their animals. But most of us don't understand how much the risks outweigh the benefits until it's too late. There are other benefits to spaying your dog or cat such as drastically reducing the chance of mammary cancer, and eliminating the odor and mess that comes along with canine heat cycles and unwanted litters. In addition, dogs and cats who are intact tend to wander looking for a mate. The best time to spay a dog is around 6 months of age and before her first heat cycle. Cats should be spayed no later than 6 months of age as well. While dogs only have about 2 heat cycles each year, cats will have repeating heat cycles every 2-3 weeks all year round until they are spayed or become pregnant. And one important thing to mention is that a routine spay is much cheaper than a spay when the pet has a pyometra.

What Are the Indications of a Pyometra?

  • intact female dog or cat
  • usually has never been bred
  • older and has had several heat cycles
  • last heat cycle was 4-6 weeks ago
  • excessive thirst
  • lack of appetite
  • vomiting
  • diarrhea
  • lethargy
  • may or may not have vaginal discharge

What Should You Do if You Suspect Your Pet Could Have a Pyometra?

  • Call your veterinarian immediately and let them know this is your concern
  • Get in to see the vet ASAP
  • If this diagnosis is confirmed, surgery should be done without delay

We took some photos of May's surgery today, and with her dad's permission, we're sharing them with you. Please be aware that some of these photos could be considered graphic.

May's Pyo

May is now recovering well in her kennel. Snuggles and tail wags aplenty. Dad has promised to continue the extra love and attention while she recovers at home. For the next 2 weeks, she'll need to take it easy, short leash walks instead of running around outside on her own, no jumping up and down from the couch or bed - dad will have to help, and most importantly, wearing her e-collar.

This is a great opportunity to express the importance of wearing her e-collar. Chances are she won't want to. I know my pets don't! But much like the mandatory mask situation we are all in, the inconvenience and discomfort of wearing it FAR outweigh the risk of not wearing it. It will require more effort on the part of the pet owner. Eating and drinking will be a new adventure, but she WILL learn to adapt. Dad can take it off when he's within arm's reach of her, but it is imperative that she wear it when she's alone. (Graphic description ahead) Most people think the cone is to keep pets from licking their wounds, and that's true, but there's more to it. She will be in pain and her instinct will be to lick and bite at her wound. If she has access to it, she could open the incision. Just under those sutures are her intestines and the sutures are all that's holding them in… We've seen it happen and it's not pretty. We promise we won't ask you to keep the cone on to make your lives miserable!! It's really important that the incision has time to heal.

She'll also need to take her pain medication and all of her antibiotics. That's really important as well. We need to be sure there's no infection. She'll have a recheck with Dr. Nichols in 2 weeks to make sure she's healing properly.

So that's May's story. We tell it to you to give you the knowledge that so many don't have. If you have questions about having your pet spayed, reach out to your veterinarian today- it could save your pet's life.