Dog laying down

What is pyometra?

Pyometra literally means 'pus in the womb' and is seen a lot less commonly these days due to increased awareness about neutering, but it is still found in any vet's consulting room the length and breadth of the UK all year round.

This is one of the most well-known and serious, life-threatening conditions for any bitch to endure.

How can I tell if my bitch has pyometra?

Pyometra, or 'pyo' for short, can present from the obvious - thick, brownish pus seeping from the bitch's vulva - to the much vaguer symptoms of being a bit quiet and perhaps just off her food. The reason for this wide spectrum of clinical signs boils down to both how long the pyo has been established and whether the creamy, festering pus is being allowed to drain out from the womb or not.

Common signs

Some, or all of the following signs may be seen:

  • a noticeably increased thirst (polydipsia)
  • licking her private parts
  • an unusual and smelly discharge from her private parts
  • painful or swollen abdomen
  • tiredness
  • depressed
  • not eating
  • fever
  • greyish gums
  • vomiting 
  • diarrhoea 

What causes pyometra?

Why all of a sudden does the bitch's uterus decide to produce and subsequently fill up with horrid, thick pus? Unfortunately, the answer isn't a simple one, as pyometra can be caused by one or a combination of underlying factors. For instance, it can be the tiny, microscopic behaviour of the womb lining itself, likely from hormonal imbalances. Or, in some cases, a source of infection - usually 'ascending', meaning it enters the reproductive tract at the vulva from the outside world and creeps up, or comes via the bloodstream from another infected area of the body. If the bitch has also recently given birth to a litter, an inflamed womb with bruised or exhausted and vulnerable tissues can also act as a focus for infection to set in.

How can pyometra be treated?

Initial investigation may include blood tests, ultrasound, x-rays or even the decisive exploratory laparotomy. Treatment options depend on a number of issues, but your vet may advise surgical removal of the infected uterus. Your vet may advise intravenous fluids, antibiotics and pain relief first to best prepare for the surgery. More recently, a short course of the same injection used for cases of 'misalliance' (mis-mating) has been shown to expel pus effectively from an infected uterus and normalise the bitch even further, making them a safer candidate for successful treatment.

Why can't antibiotics be used to fight this infection?

Due to the thickness and amount of pus, any antibiotics injected or ingested orally are delivered to the diseased tissues via the bloodstream and rarely penetrate the infection effectively. Even if they did, the bitch's underlying medical conditions (such as abnormal hormone levels), would normally mean a recurrence post treatment. So to cure a bitch with pyometra, your vet may surgically removal the infected uterus and also remove the bitch's ovaries at the same time (i.e. carry out a bitch spay).

What is the difference between pyometra spay and a normal spay?

The main differences operation-wise between a pyometra spay and a normal routine spay can be an increased risk of abdominal contamination to the patient (due to infected tissues that may be fragile and break down when touched), and cost for the owner, as many pyometras will present at night in emergency hours, requiring full clinical investigation, including perhaps a couple of days of hospitalisation on fluids.

Preventing pyometra

Pyometra is certainly one of the biggest reasons vets advise you to get your bitch spayed if you're not planning to breed from her. Spaying a bitch with pyometra is usually 100% successful, with the patient typically making a full and uneventful recovery with a good prognosis. Speak to your vet about the reasons for and against having your dog spayed.

Article author

This article was written by Marc Abraham, a vet based in Brighton who regularly appears on UK television.

Think your dog may be affected?

If you're worried about your dog's health, always contact your vet immediately!

We are not a veterinary organisation and so we can't give veterinary advice, but if you're worried about any of the issues raised in this article then please contact your local vet practice for further information.

Find a vet near you

If you're looking for a vet practice near you, why not visit the Royal College of Veterinary Surgeons' Find a Vet page.