Off Topic

I think, therefore I harm


Pyometra is a lethal disease seen in the female of several animals. While most often seen in dogs, pyometra frequently affects cats, ferrets, rabbits and other rodents such as rats. Pyometra is the infection of the uterus, which fills with pus, and thus could only affect unsprayed females.


During a heat, the lining of the uterus changes and the cervix opens. Normally, at the end of the heat, the cervix closes back and the lining returns to normal. However, in some occasions, the return to normal does not occur because of a bad response to progesterone (an hormone produced by the body of females as part of the menstrual cycle and during pregnancy). In this case, the uterus becomes a favorable environment to bacteria (such as E. coli) which have migrated from the vagina. The uterus fills with pus. Cyst or hyperplasia (an enlargement of an organ, which may turn into a tumor) of the lining of the uterus may develop.


There are two types of pyometra. Open pyometra is when the cervix has remain open. When the cervix has closed, it is called a closed pyometra.

In the case of an open pyometra, fluid will leave the body through the vagina. This fluid is composed of a mix of pus and blood, and normally causes an unpleasant odor, which is often the first perceptible sign. The fluid may cover the butt of the animal, which upon inspection from the inexperienced owner may look like just blood, but upon thorough examination will appear like a mix of a yellowish sticky fluid and blood. The animal may leave blood spots in several places of the house, in particular in places where it sleeps, which may also be one of the first symptoms which an owner may notice. Because of the presence of the fluid, open pyometra is easy to notice and diagnose, and may be easier to treat, especially if diagnosed and treated quickly.

In the case of a closed pyometra however, as the cervix has closed, no discharge occurs and the disease may be very difficult to notice. Furthermore, the pyometra may progress faster as the fluid remains inside the uterus. When the uterus has filled, it may rupture and allow the pus to fill the abdomen, causing a rapid death. Closed pyometra is harder to detect, and therefore may be harder to treat. Closed pyometra is rarer than open pyometra.


The most obvious symptom of an open pyometra is a discharge of fluid (which is a mix of pus and blood) from the vulva. Because the fluid could cover the entire rear of the animal, the owner could easily think that it is blood coming out of the anus instead, leading him/her to try to diagnose the disease from the wrong symptom. In case of a closed pyometra, there may be no obvious symptom however.

Other symptoms for both types of pyometra may be loss of appetite, lethargy (extreme fatigue), increase in drinking and urinating, and vomiting. If there is more than one animal of the same type in the environment, some of these symptoms may take more time to notice or remain unnoticed completely. Pyometra may be accompanied by a strong fever, which might not be noticeable without the use of a thermometer because an increase in temperature is not always easy to notice through the fur of the animal.

Other symptoms, which can only be recognized by a veterinarian during an examination, are dehydration, enlarged uterus (which could be noticed by palpation through the abdomen and visible through x-rays) and presence of a fluid in the uterus (with ultrasound).


Since pyometra is considered a serious (often lethal) disease which develops quickly, often in a matter of a few days, it is primordial to bring the animal to a veterinarian promptly after diagnostic. A veterinarian will immediately give intravenous fluids to the animal to compensate for dehydration, and antibiotics to slow down the infection and prevent any further propagation (possibly to other organs).

If diagnosed very quickly, pyometra may be treated with combination of antibiotics and a drug which contracts the uterus and pushes the pus out of the body. However, this method has a very low rate of success and is normally only attempted in the case of a female which is a breeder of high value. Furthermore, the rate of return of the disease is high.

The preferred treatment is emergency ovariohysterectomy (surgical removal of both uterus and ovaries, also called spray), which has the advantage of quickly removing the infection and all chance of recurrence. This is currently considered the most effective treatment. The operation is somewhat more complicated than a routine spray, however, as the veterinarian has to take precautions to avoid the spread of infection. Also, the operation is more risky as it is performed on an already sick animal, whereas a spray will only be performed while the animal is healthy. However, the risks and rate of failure are considered low.

The veterinarian will usually prescribe Clavaseptin or Clavamox (an antibiotic), which the owner needs to administer to the animal.


This operation is complicated, and therefore is, unfortunately, very expensive. The overall cost for the procedure (including antibiotics) could reach several thousands of dollars for dogs, while for cats they could reach close to a thousand dollars (price may vary in different clinics and regions). It is advised when requesting a quote to ensure what is included, in particular if the quote is low. For comparison purpose, a routine spray is usually well under $200.


Pyometra is a serious and painful disease, which is often lethal, but can be prevented.

The only mean of prevention is sterilization (spray). Since pyometra affects the uterus, it is almost impossible for a sprayed female to develop the disease. The animal should be sprayed as soon as possible, preferably before the first heat. If the owner intended to breed the animal, it should be sprayed immediately after the last pregnancy.

Beside the advantage as a prevention of pyometra, there are many other advantages to sterilization.

Copyright © 2011 Tom Duhamel. Unrestricted use for educational purpose. Any other rights reserved. Link rather than copy.


5 comments on “Pyometra

  1. Pingback: Why you should sterilize your cats « Tom Duhamel

  2. emmagreenie
    April 30, 2012

    Thanks for the information! I have been hearing a lot about pyometra lately, and one of my friend’s dogs had to get surgery for it. Good to know exactly what it is!

  3. Robi Bautista
    July 29, 2014

    Unfortunately i read this article 3 days late when my Dog died because of Pyometra if i could turn back time 😥

  4. Robi Bautista
    July 29, 2014

    I Miss my Mojita 😥 i will be miss our bonding and friendship she is different i will never forget her she became part of our family for almost 10 years and i think i will miss her every time i go home i will be miss our daily routine playing with her preparing her food sleeping beside her, when she’s hiding before shower time when she’s so excited to see us and releasing our stress from work i wish i could see her in heaven waiting for me. See you soon my Baby Mojita 😥 we love you.

    • Tom Duhamel
      August 3, 2014

      I’m really sorry about the loss! I nearly lost a cat to Pyometra years ago, which prompted me to research and eventually write this post, in the hope that it could be helpful to others. I hope you will spread the word regarding this easy to detect, and even easier to prevent, illness, in order to save lives and tears.

Any question? Have a tip to share? Have a different opinion?

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s


This entry was posted on March 13, 2011 by in Cats, Pets and tagged , , , , , .


%d bloggers like this: