The Emergency Pyometra in Dogs - common and risky

Pyometra in dogs is a potentially fatal condition that is all too common in entire female dogs.  It is one of the big reasons why vets recommend all females should be spayed.  For those unfortunate dogs that develop pyometra, emergency life-saving surgery is the best option to ensure a full recovery.


A pyometra is an infection of the uterus of entire female dogs, typically occurring in middle age and older.  When we think of an infection we imagine that antibiotics are the main way we treat and cure it.  It's not so simple in this case.  In a dog with a pyometra the uterus essentially becomes like a giant pus-filled balloon and there is no way that the antibiotics can even control the infection let alone cure it.  It's unfortunately a bit more complicated than that.

the uterus becomes like a giant pus-filled balloon

The Risks

Lets first go back to the beginning.  While older individuals are at a much higher risk of developing pyometra, it can happen in younger animals too who have not been spayed.  In fact this is one of the major reasons for speying in the first place with intact females having around a 20-25% (1-in-4) chance of developing the condition by the time they reach 10 years of age.  There are reported risk differences between breeds and in some breeds having a litter of pups may offer some protection.  But for all entire female dogs there is a real risk of developing a pyometra.

And although the risk increases with age, younger individuals can also be affected occasionally too.  Hormonal treatment given to prevent seasons or given after accidental mating to prevent pregnancy is also thought to increase the risk of a female dog developing pyometra.

The death rate of pyometra is about 5% with treatment and without treatment death should be considered as a certainty.

1-in-4 entire females will develop pyometra by the age of 10 and 5% of these will die

Symptoms of Pyometra

A typical pyometra develops within 2 months of a season and there are a number of things you might notice in your dog.  They are generally pretty vague and include:

  • lethargy

  • inappetence

  • weakness

  • vomiting

  • diarrhoea

  • increased thirst

  • increased urination

  • an enlarged abdomen.

The clearest sign of a pyometra is the presence of pus draining out of the vagina.  Your dog may keep themselves clean so this discharge may not be obvious.  When this occurs it is known as an open pyometra because the cervix is still open to allow this drainage. We don't always see this discharge as if the cervix is closed then a closed pyometra develops.  In this instance there is no-where for the pus to drain and as a result the patient often becomes unwell faster and is more severely affected at the time of diagnosis.


Any unwell entire female should be considered to have a pyometra until proven otherwise.  How then will your vet diagnose this condition?  A blood test is often taken to check on general body health and this will give clues as to the problem.  Xrays can be useful and give a diagnosis if the uterus is very enlarged.  When a pyometra is small or just starting though, xrays are not very sensitive and so may miss it completely.  Xrays can also not distinguish early pregnancy from infection.  This is because the bones of a developing puppy only show up a couple of weeks before birth.  Ultrasound then is the best method of diagnosis.  It can pick the condition up at an earlier stage and can easily distinguish between pyometra and pregnancy.  It is also safe and quick to perform when available.


Once a diagnosis is made, prompt treatment is needed to reduce the risk of the uterus bursting as well as other severe toxic complications of advanced pyometra.  In all patients antibiotics will be started and a swab may be taken to confirm there is no resistance to this antibiotic.  A decision then needs to be made.  Surgical or medical treatment.


For any dog not wanting to be bred in the future, a complete ovariohysterectomy is the treatment of choice because it not only cures the condition but also prevents it from happening again.  Depending on the condition of the patient stabilization with IV fluids and medication may be needed before undertaking surgery to reduce the risk of the procedure.  It must be mentioned though that any anaesthetic and surgery carries a risk to the patient, especially one who is older and unwell.  None the less, in the vast majority of patients surgical treatment is by far the best choice and the vast majority will recover uneventfully after a short post-operative period of hospitality.

A typical pyometra develops within 2 months of a season and these are the symptoms: lethargy, inappetence, weakness, vomiting, diarrhea, increased thirst, increased urination, an enlarged abdomen


For patients who are planned to be used for breeding then there may be the option of medical treatment.  For those who are severely unwell however surgical removal of the uterus may in fact be safer, as all the toxins and inflammatory substances will be quickly removed and not able to continue damaging the body as a whole.

It typically takes 2-4 days for medical treatment to result in an improvement in the patients condition.  Also for those with a closed pyometra there is an increased risk of the uterus bursting which can be catastrophic.  For dogs where drug treatment is desirable there are several different protocols which will depend on your vets experience and availability of drugs as these are not drugs that will be stocked by everyone, especially if your vet doesn't have a big breeding client base.

The big draw backs of medical treatment are time taken for an improvement to take place, a risk of treatment failure and uterine rupture, and also the significant risk that a pyometra will recur.  There is up to a reported rate of 77% recurrence within just over 2 years following medical treatment of pyometra.  This means that breeding should take place as soon as possible and once completed the patient should be spayed promptly.


Of course prevention is much better than cure.  Having a bitch spayed, either by ovariohysterectomy or ovariectomy, completely removes the risk of pyometra so long as the ovaries are completely removed.  This is because active ovaries are essential for a pyometra to develop.  Ovary-sparing sterilization is not common and does nothing to remove the risk of a pyometra from developing.

As for timing, this is a huge topic which I discuss in depth in my article when to spay a female dog.  There is much research going on in this area and our standard dogmatic recommendations are being challenged.  What is right for your individual dog depends on their breed and which risks you decide you are happiest to accept.

As a final comment, while pyometra can affect cats it is in fact very uncommon.  This may be because they are less susceptible or because the vast majority of our pet cats are speyed.


I hope this video answers the questions you may have had about this common condition but if you do have questions, comments or topics you would like covered in future articles then please leave them below.  I would love to hear from you.  Also be sure to sign up to our newsletter so you don't miss out on future content and to let me continue to help you and your dog live healthier, happier lives.

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