Pyometra is a life-threatening infection in which the uterus of an unspayed female fills with pus. It is one of the most common emergencies in intact bitches — roughly one in five unspayed female dogs (19–24 % in Swedish insurance data) develops pyometra by the age of 10 — and it also occurs in cats. The condition usually needs emergency surgery, and recognising the signs early can save your pet's life. This article explains what the symptoms look like, how quickly pyometra develops, why antibiotics alone are not enough, how it is treated at Saari Animal Clinic, what recovery involves and how to prevent it.
What are the symptoms of pyometra in dogs?
The clearest sign is a pus-like discharge from the vulva — yellowish, brownish or the colour of old blood, often foul-smelling — and the dog licking her rear end more than usual. This is an "open" pyometra. In a "closed" pyometra the cervix is shut, nothing drains out and the dog gets sicker faster with vaguer signs: drinking and urinating much more, refusing food, tiredness and apathy, vomiting, a swollen or painful belly, fever or in severe cases a below-normal temperature. If an unspayed bitch is listless and drinking a lot in the weeks or months after her heat, see a vet the same day.
How does pyometra start and how fast does it progress?
Pyometra typically develops 1–2 months after a heat, and usually within four months of it, when progesterone has thickened the uterine lining and bacteria — usually E. coli from the dog's own gut — climb up through the cervix. An open pyometra may smoulder for days to weeks with discharge as the main sign; a closed pyometra can make a dog seriously ill within days, because toxins and bacteria pass from the uterus into the bloodstream. Around 60 % of all dogs with pyometra already have sepsis when they arrive at the clinic, and the proportion is higher when the cervix is closed. Any suspicion of pyometra is therefore an emergency: the sooner surgery is done, the better the outcome.
What causes pyometra and which dogs get it?
The underlying cause is hormonal: after every heat, progesterone prepares the uterus for pregnancy, and over the years these repeated cycles cause cystic thickening of the lining, which is an ideal breeding ground for bacteria. Pyometra is therefore a disease of intact (unspayed) females, most often middle-aged and older — on average around 7 years, and in Finnish data the typical patient is about 9 — but it can occur after the first heat. Oestrogen injections given to prevent pregnancy after an unwanted mating are a well-documented risk factor. Breed matters a great deal: in Swedish insurance data more than half of intact Bernese Mountain Dog, Great Dane, Leonberger, Rottweiler and Irish Wolfhound bitches develop pyometra by age 10, whereas in Swedish and Finnish studies the Finnish Spitz, Dachshunds, German Shepherds and mixed-breed dogs have a clearly lower risk.
Can pyometra heal on its own or with antibiotics?
No. Untreated pyometra is life-threatening: the uterus can rupture, and the infection leads to sepsis, kidney damage and peritonitis. Antibiotics alone cannot clear pus from a closed uterus. Medical treatment with hormones plus antibiotics exists only for selected cases — a young, otherwise healthy breeding bitch with an open pyometra and no signs of sepsis — and even then pyometra comes back at a later heat in roughly one dog in four (reported range 0–85 % depending on the protocol), so the bitch should be bred at the very next heat and spayed once her breeding career is over. For all other patients surgery is the treatment of choice, and at Saari we recommend it in nearly every case.
How is pyometra diagnosed?
We examine the dog and take a blood sample to check the white blood cells and the kidney and liver values — more than half of dogs have a raised white cell count (most often in closed pyometra), and a low count is a warning sign of peritonitis — and confirm the diagnosis with an abdominal ultrasound, which shows the fluid-filled, enlarged uterus within minutes. Because closed pyometra can look like many other illnesses, we scan any unspayed bitch who is unwell in the weeks or months after a heat, even without discharge.
How is pyometra treated?
The treatment is emergency surgery to remove the infected uterus and the ovaries (ovariohysterectomy) — the same operation as a spay, but on a sick patient with an enlarged, fragile uterus, so it is done with extra care. Before surgery the dog is stabilised with intravenous fluids and antibiotics, and vital functions are monitored continuously under inhalation anaesthesia. The prognosis with surgery is good: over 90 % of dogs recover, and once the uterus and both ovaries are removed the disease cannot return; the rare "stump pyometra" happens only if a piece of uterus and ovary is left behind at surgery. Delaying surgery is what turns pyometra from a routine emergency into a fight for life.
How much does pyometra surgery cost?
Pyometra surgery is priced case by case, because the operation, the fluids and antibiotics, the anaesthesia time and any hospitalisation depend on the size of the dog and on how ill she is when she arrives. You receive an estimate before surgery. For comparison, a planned spay of a healthy bitch costs 483–753 € depending on weight — an emergency pyometra operation costs more than that, and the earlier the dog is brought in, the less intensive care she needs. Direct insurance billing is available for LähiTapiola, Agria and Pohjola customers.
How long is recovery after pyometra surgery?
Most dogs are noticeably brighter within a day or two of surgery, once the source of the infection is gone. They go home with pain relief and, when the vet judges it necessary, a short course of antibiotics; wear a recovery suit or cone for 10–14 days, and are kept to short lead walks until the sutures are removed or have dissolved at about 10 days. We re-check the wound and the general condition after surgery, and repeat the blood test if kidney values were raised. Full recovery normally takes two weeks.
Do cats get pyometra?
Yes, though less often than dogs. In cats the signs are similar — lethargy, poor appetite, increased drinking, a swollen belly — but up to 40 % of queens show no visible discharge, cats hide illness well, and they are affected younger (typically around 4 years), so the disease is often further advanced when noticed. The treatment is the same emergency ovariohysterectomy, and the prognosis with surgery is good. Spaying (removing the uterus and both ovaries) prevents it, apart from the rare stump pyometra described above.
How can pyometra be prevented?
Spaying all but removes the risk, because the uterus and both ovaries are removed — the only exception is the rare stump pyometra when a piece of ovary or uterus is left behind. We do not, however, recommend spaying every healthy female as a matter of routine: the procedure has both benefits and drawbacks, and how they balance out differs from one animal to the next. We go through them with you and make the decision together — read more on our spaying page. If you keep your bitch intact, learn the signs and check her closely in the two months after every heat, and avoid oestrogen-based "mismating" injections, which clearly increase the risk; hormonal heat-suppression treatments (progestogens) are also linked to pyometra, although a large Finnish study did not confirm a strong effect. Ask us about safer alternatives.
When should I contact the vet?
Immediately — the same day — if an unspayed female shows discharge, is listless, drinks a lot or refuses food in the weeks or months after a heat. During business hours call Saari Animal Clinic in Vaasa on (06) 321 7300; we reserve daily acute appointments. Evenings and weekends, call the regional emergency number 0600 399 299. Pyometra does not wait until Monday.
Sources
- Hagman R. (2018): Pyometra in Small Animals. Veterinary Clinics of North America: Small Animal Practice 48(4):639–661. theclinics.com
- Jitpean S. ym. (2014): Outcome of pyometra in female dogs and predictors of peritonitis and prolonged postoperative hospitalization in surgically treated cases. BMC Veterinary Research 10:6. ncbi.nlm.nih.gov
- Merck Veterinary Manual: Cystic Endometrial Hyperplasia–Pyometra Complex in Small Animals. merckvetmanual.com
- Cornell University Riney Canine Health Center: Pyometra. vet.cornell.edu
- Egenvall A. ym. (2001): Breed risk of pyometra in insured dogs in Sweden. Journal of Veterinary Internal Medicine 15(6):530–538. doi.org
- Jitpean S. ym. (2012): Breed variations in the incidence of pyometra and mammary tumours in Swedish dogs. Reproduction in Domestic Animals 47(Suppl 6):347–350. doi.org