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Pyometra in dogs

Female dogs that have not been spayed (neutered) are at risk of getting a life threatening infection of their uterus (womb), called a pyometra. This infection requires urgent veterinary attention.

This article was written by a FirstVet vet

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Symptoms of pyometra

  • Early signs are not always obvious and can be vague
  • A vaginal discharge may or may not be present
  • Lethargy or being off-colour
  • Drinking more and urinating more, or drinking less if vomiting
  • Vomiting
  • Anorexia in some cases
  • Season or heat may last longer than normal
  • Licking the vulva more than normal
  • Swollen or painful abdomen
  • Collapse

Cause of a pyometra

The infection is caused by a bacterial infection, most commonly Escherichia coli (E. coli), which is found in faeces. A pyometra usually occurs a few weeks after a female dog has finished her last season. The infection results in the uterus becoming filled with pus. In some cases a mal-odourous vaginal discharge is present. However, in other cases the infection remains trapped inside the uterus which, if left untreated, can lead to dehydration, toxaemia, kidney failure, and occasionally death.

Every time a female dog has a season or heat (normally twice a year) they experience the hormonal changes associated with pregnancy, regardless of whether they are pregnant or not. The changes in the uterus that occur during each cycle make infection more likely with age. Therefore, pyometra is usually seen in older, female dogs who haven’t been neutered. However, the infection can happen in a bitch of any age. Hormone changes can also lower their immunity, and therefore increase their risk of infection.

Progesterone based hormone injections that are used to prevent seasons, or for treatment of other conditions, can also increase the risk of a pyometra developing. This is because they can cause changes in the uterus, which are similar to those seen during a season.

What can you do to help your dog?

Being vigilant and spotting the signs early is key. Once a dog has developed a pyometra, the treatment is usually emergency surgery to remove the uterus. The sooner this surgery is performed, the better the chance of survival. A dog that has been spayed cannot develop pyometra, so if you do not plan to breed puppies, please spay your bitch. A very small number of cases subsequently develop pyometra if the neutering procedure was not carried out correctly and a portion of the ovary tissue was left behind, or certain hormone therapies have been administered.

Treatment of a pyometra

Your vet will take a thorough history of your dog. They will want to know when the dog’s last season was, how they have been behaving, and how much they are drinking. Your vet may recommend an ultrasound scan to assess your dog’s uterus, and a blood test to check their kidney and liver function, hydration status, and levels of red and white blood cells.

Dogs are usually given intravenous fluids, or a drip, straight away, to help ensure they are hydrated and to support their circulatory system, and their liver and kidneys. Emergency surgery is carried out as soon as the patient is stable for the general anaesthetic.

When is it time to visit a vet?

  • If you suspect that your dog has a pyometra, please contact your vet immediately.
  • Alternatively, book the next available appointment with one of our FirstVet vets who will be able to provide emergency advice and guide you to your nearest vet clinic.

More information from The Blue Cross can be found here.

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