Pyometra in Dogs: Symptoms: Diagnoses and Treatment

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    What is Pyometra?

    pyometra uterus
    Phoot Credit: United Vet Clinic

    Pyometra in dogs is a secondary infection that develops in the female reproductive system as a result of hormonal changes. The hormone progesterone stays increased for up to two months after estrus (heat), thickening the uterine lining in preparation for pregnancy. 

    What Causes Pyometra in Dogs?

    Pyometra in dogs is an infection of the uterus caused by bacteria. The most likely culprit is E.coli, which is widely found in feces. A uterine infection in a female dog usually appears a few weeks after her heat cycle. The uterus may be packed with pus, and there may be a foul-smelling vaginal discharge. In many cases of pyometra, however, the pus remains trapped inside the uterus. If left untreated, this type of infection can lead to dehydration, sepsis, renal failure, and even death.

    Even if a female dog does not become pregnant, the hormonal changes linked with pregnancy occur every time she goes into heat (usually twice a year). As the dog ages, these hormones produce changes in the uterus, making infection more likely. The dog’s immune system is further stressed by the hormone variations that occur with each heat cycle, increasing her risk of illness.

    Injections of progesterone-based hormones, which are routinely used to prevent a dog from going into heat or to treat other diseases, can also increase the risk of pyometra developing. These hormone treatments cause uterine changes that are similar to those seen during a natural heat cycle.

    Who’s at Risk of Developing Pyometra?

    senior black laborador wearing a red collar

    Pyometra is most prevalent among older female dogs that have not been spayed. This sort of uterine infection, on the other hand, can strike any unspayed female dog of any age.

    What are the Symptoms of Pyometra?

    Clinical symptoms of pyometra in dogs is often dependent on whether or not the cervix remains open. If the cervix is open, the uterus will likely leak pus via the vaginal canal or an abnormal discharge may be noticed on the skin or hair under the affected dog’s tail as well as bedding and furnishings. Other symptoms include fever, lethargy, anorexia, and depression.


    When the cervix is closed, the pus that develops cannot drain to the outside. It builds up in the uterus, causing the abdomen to expand. Toxins are released by the bacteria, which are taken into circulation. Closed pyometra causes dogs to get seriously unwell very quickly. They’re anorectic, listless, and extremely depressed. Vomiting and diarrhea may also occur. 


    Toxins produced by the bacteria impair the kidney’s capacity to retain fluid causing their urine production to rise, and many dogs compensate by drinking excessive amounts of water. Pyometra with an open cervix and one with a closed cervix can both produce an increase in water intake.

    How Can Pyometra Be Prevented?

    dog being spayed

    The best and only approach to avoid pyometra is to spay your dog. Spaying reduces the hormonal stimulation that produces heat cycles as well as the uterine changes that allow pyometra to develop. Spaying a healthy dog with a healthy uterus is significantly safer (and cheaper) than putting a sick dog with an atypical uterus through surgery. Female dogs should be spayed before their first heat cycle, however most older canines are also good candidates for the treatment.

    How is Pyometra Diagnosed?

    Dogs who are displaying signs of pyometra should be seen immediately by a veterinarian. To diagnose, vets look into your dog’s medical, physical and behavioral history such as how much food and water they’ve been intaking as well as the date and duration of her previous heat cycle. Blood tests, as well as an ultrasound of her uterus, will usually be performed to assess her liver and renal function, red and white blood cell counts, and hydration status.

    What is the Treatment for Pyometra?

    vet removing pyometra uterus from dog
    Photo Credit: The Information Website for the Health & Welfare of the St Bernard

    An ovariohysterectomy, or surgical removal of the diseased uterus and ovaries, is the chosen therapy aka a spay. When pyometra in dogs is detected early, these dogs have excellent surgical prospects. At this point, the procedure is a little more involved than a conventional spay. However, most dogs are diagnosed with pyometra after they are already sick, which necessitates a more involved and difficult surgical operation and a lengthier stay in the hospital. Before and after surgery, intravenous fluids are necessary to keep the dog stable. Antibiotics are often prescribed for two weeks following surgery.

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