Pyometra in dogs: what to look out for

There’s no simple answer, but pyometra is usually caused by one or more underlying factors. These include hormonal imbalances and bacterial infection.

In female unspayed dogs, the hormone progesterone causes the thickness of the uterine wall to increase after each oestrus cycle (a female dog’s reproductive cycle). Over time, this can lead to cysts forming. These cysts leak fluid, creating the perfect environment for bacteria in the uterus to multiply rapidly, leading to an infection. Usually, pyometra will occur between two and eight weeks after your dog’s last season. It’s also more common in older female dogs.

It's important to keep a close eye on your unspayed female dog, for any pyometra symptoms. These can include:

• Thick pus discharge from the vulva (open pyometra only)
• Drinking and urinating more than usual
• Vomiting
• Panting
• Diarrhoea
• Eating less than usual
• Fever
• Lethargy
• Swollen abdomen

Pyometra can be classed as open pyometra, or closed pyometra. Open pyometra happens when your dog’s uterus becomes infected, but her cervix is open. The pus that forms within her uterus will drain out via the vagina.

Closed pyometra can be more dangerous, because while your dog’s uterus is infected, her cervix remains closed. That means any pus that forms cannot drain out. As the pus builds up, there’s a danger that the uterus could rupture, or the bacteria from the pus could start to infect her bloodstream. Both possibilities can be life-threatening, which is why prompt treatment is so important.

Pyometra is a medical emergency. If you’re concerned your dog is showing any of the symptoms listed above, make sure you contact your vet immediately. It’s a good idea to keep track of when your dog’s last season was, as this can help your vet decide if pyometra is the probable cause of your dog feeling unwell.

If pyometra is suspected, a dog will often be given an ultrasound scan to confirm the diagnosis, along with blood tests and potentially X-rays. Usually, spaying is the recommended treatment for both closed and open pyometra. This is a more complex procedure than a regular spaying operation and carries a higher risk from infected tissues. Antibiotics and pain relief will usually be given, plus intravenous fluids to try and reduce shock. Sometimes, a short course of injections can help expel pus from an infected uterus, which can result in safer surgery.

Round-the-clock care will also be needed during recovery, so an emergency pyometra procedure will usually cost significantly more than a routine spaying operation. If your dog has closed pyometra, then it’s vital that she’s operated on as soon as possible. Dog insurance can help to ensure that you can afford the best possible care for your dog.

Most bacterial infections can be treated with a course of antibiotics, so some owners may wonder why pyometra doesn’t fall into this category. Due to the amount and thickness of the pus that forms within the uterus, most antibiotics that are injected or swallowed simply won’t have any effect.

Occasionally, mild cases of open pyometra may be successfully treated with a course of antibiotics and hormone treatment, but this would usually only be considered in valuable dogs used for breeding. Even then, the chances of pyometra recurring sometime in the future are high. This treatment option may be offered by some vets on a case-by-case basis.