Pyometra is an infection of the uterus that can occur in female animals that haven't been spayed. It can be in an open or closed form (see next paragraph). Pyometra typically occurs a few weeks after a heat cycle, as changes in hormones create the ideal conditions for harboring bacteria in the uterus. Pyometra happens more commonly in older pets, as they are not as able to fight infection. Isolated organisms are frequently those found in the intestinal tract like E. coli. The incidence rates of canine pyometra vary in the literature, but range from 23-45 %. The disease is less common in felines.
Symptoms of pyometra vary and can include low energy, low appetite, increased thirst, and increased urination. In an open pyometra, a visible vaginal discharge of pus is present. These patients may or may not seem very ill, and frequently clean the genital area. In a closed pyometra, there may be no external symptoms, and signs are typical of any generalized illness. As the disease progresses, toxins build up in the uterus, and are absorbed into the blood stream. These patients can become very ill and will often experience vomiting, diarrhea, lethargy, depression, weight loss, fever, increased water consumption, increased urination, and abdominal distension. In severe cases shock, uterine rupture, sepsis, systemic inflammatory response syndrome, multiple organ dysfunction syndrome, and death can occur.
Diagnosing an open pyometra is relatively simple, as a visible vaginal discharge is present. A closed pyometra is much more elusive. A fluid-filled uterus can sometimes be palpated on exam; but it is usually identified on xrays or ultrasound. Vaginal cytology and blood work can also be helpful. A recent history of a heat cycle (3-8 weeks ago) will also alert your veterinarian to the possibility of a pyometra.
A closed cervical pyometra is a medical emergency. The dog or cat should be stabilized with iv fluids, antibiotics, and other treatment as needed. As soon as possible an emergency ovariohysterectomy should be performed. Recovery is 80-100% successful depending on how early the disease was diagnosed, as well as the health, and age of the patient. Antibiotics are typically administered for 1-2 weeks, and long term health problems can occur.
In stable patients medical management can be attempted with prostaglandin injections; but this form of treatment is not ideal. These dogs and cats should be hospitalized on IVs and antibiotics, and are often ill for several days. Although medical management is not the preferred treatment, it can be attempted for animals that are used for breeding. Pyometra often occurs again with subsequent heat cycles.
The best way to prevent pyometra is to have your cherished companion spayed (ovariohysterectomy). If a female dog is spayed before her first heat cycle, mammary tumors are avoided. Other health issues such as uterine and ovarian tumors are prevented at any age that this surgery is performed. Ovariohysterectomy can also help to prevent aggression, and make your pet less likely to want to escape. Also, it is much safer to spay your female dog or cat when she is healthy, as opposed to when she has pyometra, and it is a medical emergency.