Canine Pyometra
The Silent Killer
Pyometra Is a Veterinary Emergency
Pyometra is a serious and potentially fatal infection of the uterus. Any unspayed bitch can be affected, including a young bitch or one that has previously produced a litter.
Contact a veterinary surgeon immediately if an unspayed bitch becomes unwell during the weeks following a season. Do not wait for every classic symptom to appear.
Pyometra means that the uterus has become infected and filled with inflammatory material or pus. It most commonly develops during the hormone-dominated period following a season.
The condition is more common in middle-aged and older unspayed bitches, but age does not provide complete protection. I have personally experienced pyometra in a nine-month-old bitch only days after her season.
Prompt diagnosis and treatment can be lifesaving. Delay allows infection and toxins to affect the kidneys, circulation and other organs and may lead to sepsis, shock, uterine rupture and death.
When Does Pyometra Develop?
Pyometra is commonly diagnosed within approximately two to eight weeks after a season, although the timing can vary and cases may present outside that usual period.
After a season, progesterone affects the uterus and creates an environment in which bacteria can multiply. Bacteria commonly ascend from the vagina; Escherichia coli is frequently isolated.
Hormonal medicines used to alter seasons or prevent or terminate pregnancy may affect the risk. Any such treatment must be directed and monitored by a veterinary surgeon.
Possible Signs
A bitch may show one or more of the following:
- Drinking more than usual
- Urinating more frequently or having accidents
- Lethargy, weakness or depression
- Reduced appetite or refusal of food
- Vomiting or diarrhoea
- A swollen, tense or painful abdomen
- Vaginal discharge
- Repeated licking around the vulva
- Fever, although temperature may be normal
- Pale gums, rapid pulse, collapse or other signs of shock
Not every bitch develops every sign. Some continue eating, have no fever and show only subtle changes initially.
Open and Closed Pyometra
Open pyometra
When the cervix is open, infected material can drain through the vulva. The discharge may be cream, yellow, brown, red, bloody or foul-smelling. Because many bitches clean themselves frequently, discharge may be missed.
Closed pyometra
When the cervix remains closed, there may be no discharge. Infected material accumulates within the uterus, which can enlarge rapidly. The bitch may become severely ill, and there is a risk of uterine rupture and infection spreading into the abdomen or bloodstream.
A closed pyometra can be particularly difficult to recognise because one of the most familiar warning signs—vaginal discharge—is absent.
Diagnosis
Your vet will ask about the bitch’s last season, changes in drinking and urination, discharge, appetite and behaviour.
Tests may include:
- Physical and abdominal examination
- Ultrasound examination
- Abdominal X-rays
- Complete blood count
- Blood chemistry to assess organs and hydration
- Urine testing
Blood tests often show evidence of infection or inflammation, but results can occasionally be unremarkable early in the disease. An early ultrasound may also be inconclusive.
If a bitch continues to deteriorate, prompt reassessment is important even when an earlier examination or test appeared normal.
Treatment
The recommended treatment for most bitches is emergency ovariohysterectomy: surgical removal of the infected uterus and ovaries.
Pyometra surgery is more complex than a routine spay because the uterus is enlarged, infected and fragile. The bitch may need intravenous fluids, antibiotics, pain relief and stabilisation before and after surgery.
Medical management may sometimes be considered for a carefully selected, clinically stable breeding bitch under specialist veterinary supervision. It is not suitable for every case, can cause side effects, may fail and carries a significant risk of recurrence.
Surgery may still become urgently necessary if medical treatment does not work or the bitch deteriorates.
This ultrasound was taken when I was scanning a bitch 27 days after mating to confirm pregnancy. It showed a severe pyometra, and she was referred immediately to a veterinary surgeon who confirmed that she required surgery.
Read about the veterinary use of Alizin in selected pyometra cases
Prevention
Removal of the uterus and ovaries prevents future pyometra. The timing and wider advantages and disadvantages of elective spaying should be discussed with your veterinary surgeon for the individual bitch.
Having a litter does not prevent pyometra. If a bitch is kept entire for breeding, every owner should know the warning signs and monitor her carefully following each season.
Owners’ Experiences
The following experiences show how differently pyometra can present. They are personal accounts rather than diagnostic guidance, but they demonstrate why owners should act when a bitch is simply “not herself.”
Jazz
Jazz’s owner, Georgina, first noticed that she appeared lazy. Over approximately four days she stopped eating, groaned when moving and seemed to lose weight quickly. She was simply not herself.
Jazz then became sick and passed a bloody mass while urinating. Georgina had never heard of pyometra and was shocked by how quickly the illness progressed.
This occurred approximately two weeks after Jazz’s season. There had been no obvious vaginal discharge.
Charlie
Charlie was eight years old when she developed pyometra. She initially became quiet and appeared sorry for herself. Her owner, Darran, noticed that her eyes looked unusual and knew that something was wrong.
Charlie was examined by a vet and initially treated for what was thought to be a respiratory infection. Over the next few days she deteriorated, struggled to climb the stairs and appeared bloated.
She then urinated indoors, something she would never normally have done. The urine or discharge was offensive-smelling and terracotta or rusty in colour.
Darran returned to the practice, where his usual vet immediately suspected pyometra. Charlie underwent emergency surgery. Her uterus was severely enlarged and contained a considerable amount of infected material.
Charlie had also lost approximately a kilogram and a half in weight. Her owner had never previously known how serious pyometra could be.
Danni
Danni was six years old. On the Friday evening she developed loose stools and seemed slightly “off”. She had no raised temperature or discharge and continued to eat.
On Saturday, her signs still resembled a mild stomach upset. However, by Sunday morning she held her head down, appeared hunched and walked like a much older dog.
She was taken straight to the veterinary surgery. An ultrasound confirmed pyometra.
Danni received intravenous fluids and antibiotics before undergoing emergency surgery and a spay the following morning. She had remained without a raised temperature and had not initially gone off her food.
Roxy
Roxy developed pyometra shortly before Christmas. She had experienced a longer season than usual and was approximately a week beyond it when she became slightly quiet and stopped jumping onto the sofa.
That evening she was unusually clingy but continued eating and drinking normally. The following morning she seemed withdrawn and still would not jump onto the sofa. Her temperature was normal, but a brown discharge was found.
Her owner, Nicky, contacted the emergency veterinary practice and took her in despite being told that the symptoms did not appear typical.
An ultrasound showed early pyometra. Because it had been identified promptly and Roxy was stable, veterinary medical treatment was attempted with hormone injections and antibiotics.
The infection cleared, but the treatment was difficult for both Roxy and her owner. Roxy was subsequently spayed.
Angel
Angel was five years old and had been mated. At 35 days, an ultrasound appeared to show a litter of at least five puppies.
At approximately day 42 she began spotting fresh blood. There was no smell and she appeared well. The emergency vet prescribed antibiotics, and the spotting stopped within 24 hours.
On the evening of day 45, Angel suddenly refused food and water and would not get off the sofa. When her owner lifted her, she began haemorrhaging and delivering the puppies.
She was rushed to the veterinary surgery. Within a short time the discharge had changed from blood to pus, she could not stand and she became critically ill.
Angel underwent emergency surgery and required blood transfusions. The puppies were too premature to survive.
Following surgery, Angel was slow to recover from the anaesthetic and remained in the veterinary hospital for several days. She survived but experienced neurological, visual and kidney complications.
Her case demonstrates that a pregnant bitch can develop a severe uterine infection and that apparently mild or atypical symptoms can progress rapidly.
Trust Changes You Observe
Owners know what is normal for their own dogs. A subtle change, such as refusing to jump onto furniture, becoming unusually clingy, having an accident indoors or simply looking “wrong”, may be the first sign of serious illness.
These signs are not specific to pyometra, but an unspayed bitch that becomes unwell after a season should be examined promptly. If she deteriorates after an initial assessment, contact the practice again or seek an emergency reassessment.
Tally
Tally’s owners had carefully considered breeding from her, but she did not accept the proposed matings. When she reached five years old, they decided to have her spayed after her next season, following veterinary advice.
Her seasons had always been irregular, sometimes occurring only once a year, and were usually light. There seemed to be nothing unusual about her final season.
Towards the end of the third week after the season began, Tally became lethargic, went off her food and started waddling. When her abdomen was gently touched, it felt hard and she groaned.
There had been no visible discharge. Her owners telephoned the veterinary practice as soon as it opened and were asked to bring her in immediately.
An ultrasound confirmed a closed pyometra, and Tally underwent emergency surgery that day. Her vet advised that a delay might have resulted in a very different outcome.
Tally recovered from the operation but subsequently developed urinary incontinence. This gradually improved over approximately four months.
She later underwent successful surgery for several non-cancerous lumps. Tally lived until the age of ten, when she developed kidney failure.
Tula—My Own Bitch
Tula was eight years old and had produced one litter. She had an unusual season that seemed heavier than normal. My young male also showed little interest in her scent, which seemed odd because he had been very interested in her daughter only a few weeks earlier.
On the day her discharge stopped, she seemed “off”. My parents had previously lost a Sheltie after a pyometra was initially misdiagnosed as a urinary infection, so I was particularly alert to the possibility.
I am trained to perform pregnancy ultrasound scans and have my own machine. I scanned Tula but could not see anything abnormal. She did not have a high temperature.
I took her to the veterinary surgery and showed the vet my scan images. They agreed that nothing abnormal was visible. I also asked for a blood test to check her white blood cell count, but the result was normal.
Only 12 hours later, Tula was completely off her food. When I offered breakfast, she looked visibly nauseated.
I scanned her again and this time there was a large amount of fluid within the uterus. She was taken straight back to the veterinary surgery, where she underwent emergency surgery within approximately 30 minutes for a full closed pyometra.
Tula’s case demonstrates that pyometra can develop or become visible very quickly. A normal temperature, blood result or early ultrasound does not guarantee that pyometra is absent if the bitch continues to deteriorate.
Important Lessons
- Having a litter does not prevent pyometra.
- A young bitch can develop pyometra as well as an older bitch.
- A bitch with a closed pyometra may have no vaginal discharge.
- Temperature and appetite may initially remain normal.
- Early blood tests or ultrasound findings may occasionally be inconclusive.
- Drinking or urinating more can be an important warning sign.
- Subtle changes in normal behaviour should not be ignored.
- A bitch that deteriorates after an initial examination requires prompt reassessment.
After Surgery
Recovery will depend upon how ill the bitch was before surgery and whether the infection affected her kidneys, circulation or other organs.
Follow all discharge instructions carefully. Give medication exactly as prescribed, restrict exercise, prevent licking and check the incision regularly.
Contact the veterinary practice if the bitch develops:
- Increasing lethargy or weakness
- Vomiting or refusal of food
- A swollen or painful abdomen
- Redness, swelling, bleeding or discharge from the incision
- Pale gums, breathing difficulty or collapse
- Excessive drinking or changes in urination
Spaying and Pyometra Prevention
A bitch cannot develop a conventional uterine pyometra once the uterus and ovaries have been completely removed. Rarely, infection can affect remaining uterine tissue if ovarian tissue or hormone exposure remains.
The most appropriate timing of elective spaying depends upon the individual bitch, her breed, health, age, intended breeding use and stage of her reproductive cycle.
Breeders who keep bitches entire should discuss future breeding and spaying plans with their veterinary surgeon rather than relying upon a fixed age that may not suit every dog.
Further Information
American College of Veterinary Surgeons: Pyometra
This information is not intended to replace veterinary care. Pyometra is a medical emergency. If an unspayed bitch becomes unwell during the weeks following a season—particularly if she is drinking more, vomiting, lethargic, off her food, has abdominal swelling or has vaginal discharge—contact a veterinary surgeon immediately.