Pyometra in dogs and cats 

Emma Stenhouse
21 April 2022 - 4 min read
A dog after surgery

Pyometra is a bacterial infection of the uterus that can happen to any unspayed female dog or cat. 

It’s a serious condition that requires immediate vet treatment.

We asked Vet Sophie Bell to tell us more about pyometra and how to spot it and how to prevent it.

Find out how your vet will treat your pet, and whether it’s covered by your pet insurance.

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What’s pyometra?

Pyometra usually happens around four weeks after your pet’s last season has finished.

Sophie explains that, during this time after oestrus, “the hormone progesterone increases the thickness of the uterine wall. Repeated heat cycles without pregnancy can result in cystic areas that secrete fluid.

“This fluid creates the ideal environment for bacteria to thrive. Your pet’s cervix will also be relaxed during this time, which means bacteria normally found in your pet’s vagina can enter more easily.

“While the uterine wall is thickened, it’s also harder for the uterus to contract and get rid of any bacteria that has entered” says Sophie.  

When your dog or cat’s in season, they’re more susceptible to infection. “During oestrus, the white blood cells that would usually protect your pet from bacterial infections are absent within the uterus.

“This is so that they don’t damage or kill any sperm, but it also means they can’t kill bacteria at the same time,”  adds Sophie. The bacterial infection creates pus that can make your pet extremely unwell as pyometra develops.

Symptoms of pyometra

Pyometra is most likely to develop between two and eight weeks after your pet’s last season. Common early symptoms to look out for include:

  • Increased thirst
  • Lack of appetite
  • Fever
  • General malaise

As the pyometra worsens, you may notice your pet’s abdomen becoming bloated. In certain cases, they will also have discharge from their vulva. This can be foul-smelling, bloody, or both. 

Pyometra more common in dogs than cats. Around one-in-four un-neutered female dogs are likely to suffer from the condition by the age of 10.

Female dogs who haven’t been spayed but have never been pregnant are also at higher risk. 

Pyometra can often be confused with phantom pregnancy, as some of the symptoms can be similar. 

Treatment for pyometra

Pyometra should always be treated as a medical emergency. If you spot any potential symptoms in your dog or cat, you should contact your vet immediately. It’s worth keeping a note of when your dog was last in season too, as this can be useful information for your vet. 

“The only way to accurately diagnose pyometra is with an ultrasound scan” says Sophie. “Your vet may also recommend blood tests, fluid therapy, and medication to stabilise your pet prior to surgery.” 

X-ray of pyometra

Pyometra cases fall into two categories:

  • Open pyometra – occurs when your pet’s cervix is open. Any pus forming within the uterus can drain out through the vagina.
  • Closed pyometra – occurs when your pet’s cervix remains closed. Pus and fluid within the uterus cannot drain out and could cause your pet’s uterus to rupture. 

The most common treatment for pyometra is immediate spaying. “Operating on a closed pyometra is extremely time critical” says Sophie.

This is because the fluid filling your pet’s uterus could build up to the point their uterus ruptures or the bacteria starts to infect their bloodstream. Without prompt treatment, both of these scenarios can be life-threatening.   

If your pet has an open pyometra, with pus draining from their vulva, spaying is also usually the recommended course of action. But what if your cat or dog is used for breeding and you’d like them to have more litters in the future?

“In some rare cases, pyometra can be treated with antibiotics and hormones, but the risk of the pyometra recurring in the future is high. The pros and cons of this option will need to be carefully discussed in detail with your vet” says Sophie.

It’s also worth noting that spaying a pet with pyometra is more complicated than a routine spay, so can result in a more lengthy and expensive procedure. If your pet needs emergency, out of hours care, then the costs will be higher still.

Although spaying isn’t generally covered by pet insurance, it may be if it’s to treat pyometra.

We saw 445 pet insurance claims for pyometra in 2021 – 32 for cats and 413 for dogs. The average cost of a claim was high at £940.02, reflecting the need for emergency surgery in most cases.

“Spaying may be covered by pet insurance as long as its not pre-existing and the spay was recommended by a vet as part of a treatment plan,” says ManyPets’ technical claims manager, Sarah Dawson.

Spaying won’t always be covered. Your vet might recommend a different course of treatment, like medication, and then the spay would be classed as preventative and wouldn’t be covered just as regular spaying isn’t. If your dog’s had a milder pyometra in the past it could be excluded as a pre-existing condition, depending on the type of policy you have and when you took it out.

If your dog has previously had pyometra but it was more than 24 months ago, your ManyPets policy should cover treatment for a recurrence. All our policies cover conditions that ended two or more years ago and we also have a Pre-existing policy that can cover more recent illnesses.

How can I prevent pyometra in my dog or cat?

The best way to prevent pyometra is to get your female dog or cat spayed.

Spaying is a routine surgery to remove your pet’s uterus and ovaries. As a result, they’ll never suffer from the dangers of pyometra.

Your vet will be able to recommend the best age to carry out this routine operation, as well as the optimal time in your dog’s heat cycle to have the procedure. 

£15,000 a year vet fee cover with our Complete policy.

Man and dog high-five
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