Uterine Infection In Dogs and Cats

One of the many advantages to Spaying cats and dogs is the prevention of a disease called pyometra, or an infected uterus.  An infected uterus can be a life-threatening illness and a surgical emergency in many cases. There are two different forms of pyometra referred to in veterinary medicine as “open or closed”.  In the following article, we will discuss signs that your pet may have this infection, how your veterinarian will diagnose the disease, treatment options, and how to prevent the disease entirely.  Pyometra is a preventable disease by spaying your pet before the condition develops.

The term pyometra derives from the Latin which literally means “pus” and “uterus”.  That is an accurate description of what this disease is, it is a pus-filled uterus.  It only occurs in intact females (not spayed) and both dogs and cats are susceptible. In my experience, up to 1 in every 4 or 5 female intact dogs will develop a pyometra sometime in their life.  Pyometras tend to occur one to two months after a heat cycle.

Pyometras can be divided into 2 types, open and closed.   An open pyometra is characterized by pus that is actively draining from the uterus through the vulva.  In cases of closed pyometra, the cervix has completely closed and the infection is unable to drain. This results in a pus-filled uterus and a very sick dog or cat.

Signs of a pyometra include lethargy, increased drinking and urination, and not eating.  In addition, a fever may be present along with pale or dry gums. In cases of open pyometra, you may notice a bloody or pus-like discharge from your pet’s vulva.  While the exact cause of why some pets develop pyometra and others do not is not fully understood but many cases have been shown to be caused by an infection with the bacteria E. Coli.  Other predisposing or biological factors may play a role in causing the disease besides the presence of bacteria in the uterus.

If your Veterinarian suspects your dog or cat has a pyometra they will obtain a careful history to find out when your pet was last in heat, if your dog was previously bred or had puppies, or your cat had kittens.  In addition, questions around recent eating and drinking habits and energy level will be obtained.

If your pet has an “open” pyometra, your veterinarian may obtain a sample and look under the microscope for bacteria.  In open or closed cases, radiographs may be taken to look at your pets uterus and blood work to look for elevated white blood cell counts and signs of infection.  Using these tests many cases of pyometra can be fairly readily diagnosed.

Dogs and cats with pyometra should have Surgery to remove the infected uterus and cervix as well as the infection inside it.  Antibiotics alone in many cases will not resolve the infection as the underlying internal conditions are still present. The surgery is similar to a routine spay, but of course, much more involved in nature.  The infected uterus is much larger in size and pets may require advanced supportive measures before or during surgery owing to their weakened state. Carefully removing the uterus without allowing pus to drain into the abdominal cavity is an important consideration for any veterinarian performing this surgery.

Fortunately, many cases of pyometra respond well to surgical intervention along with antibiotic therapy and this is recommended for the overwhelming majority of cases.  While non-surgical options are available for some select cases, they may carry increased risks and more advanced medical therapy. The use of medications to open the cervix to drain the pus is utilized to help clear the infection in these cases.

Pyometras are a very frequent diagnosis in veterinary medicine, particularly in practices or shelters with high numbers of unspayed female animals.  They are 100% preventable by spaying your pet! If you suspect your pet has developed a pyometra, we recommend seeking immediate veterinary medical care!  Many cases of pyometra are emergencies and this infection can make pets extremely ill. Left untreated, many pyometra will be fatal. Fortunately, with swift and proper medical attention most patients recover fully.

Jeffrey Stupine, V.M.D
Medical Director
World of Animals Veterinary Hospitals