The word “pyometra” is derived from Latin “pyo” meaning pus and “metra” meaning uterus. Pyometra is an abscessed, pus-filled infected uterus. Toxins and bacteria leak across the uterine walls and into the bloodstream causing life-threatening toxic effects, without treatment death is inevitable.

What causes pyometra?

Dogs and cats, unlike humans, continue to have an active reproductive cycle throughout their lives. Each time they go through the “heat” cycle, the cervix opens up as a normal method for introduction of sperm into the uterus for fertilization. The uterine environment is set up to support the growth of the embryo and as a result, it is a perfect breeding ground for bacteria. When the cervix is open, bacteria can move into the uterus and begin to reproduce. The uterus is separated from the rest of the body and the infection can grow to a large extent without showing many systemic signs until it is very severe. If the cervix closes after the infection occurs, the uterus may fill up with pus. The bacterial toxins in the pus can cause the wall of the uterus to rot and it may even rupture. These toxins are transported into the bloodstream late in the course of the disease and may cause many of the clinical symptoms associated with pyometra.

What are the symptoms of pyometra?

Pyometra can only occur in the female of the species for obvious reasons. It usually occurs in middle age to older pets with a history of a recent (within 1-3 months prior to presentation). Symptoms include:

  • Poor appetite
  • Weight loss
  • Increased thirst
  • Increased urination
  • Lethargy
  • Vaginal Discharge

How do our veterinarians diagnose pyometra?

Diagnosis of this disease relies on a good history from the owner and a thorough physical examination. If the cervix is open and the uterus is draining, the index of suspicion is very high. In other cases (closed pyometra) radiographs (x-rays), abdominal ultrasound and blood tests will help to make the diagnosis.

How do our veterinarians treat pyometra?

Pyometra is a serious disease and cannot be ignored. Successful treatment requires surgical removal of the entire uterus and ovaries. Many pyometra patients are very sick on presentation. They must be supported with intravenous fluids to correct their dehydration as well as injectable antibiotics. Usually, these patients require a few days in the hospital before they can go home. Generally, they will be given antibiotics and pain medication at discharge.

There is an alternative to surgery that involves the use of a drug called prostaglandin. This procedure may be used in very valuable breeding stock to allow for one more litter. It can only be used on pets that have an open or draining pyometra. Attempting it in a closed pyometra might cause the uterus to rupture. Unfortunately, it requires 5-7 days of hospitalization and is very hard on the patient. Side effects from the drug include abdominal pain and severe vomiting. If a patient undergoes this procedure, she must be bred on the next cycle or the pyometra will likely return. Future occurrence of pyometra is almost guaranteed, so the pet must be sterilized after the next breeding or cycle.

What is the prognosis for pyometra?

The prognosis for this disease is related to how sick the pet is at the time of presentation, how sick the uterus is at the time of surgery and how smoothly the surgery goes. Pyometra surgery is a delicate procedure as the infected uterus is usually engorged with blood as well as being filled with pus. If the uterus can be removed with rupturing or contamination of the abdomen with bacteria, the prognosis is good. In our hospital, the survival rate for pyometra surgery is generally above 90%.

How can our veterinarians prevent pyometra?

Sterilization is the key to prevention of pyometra. We prefer to sterilize pets before they are a year old, but our veterinary team can safely perform this surgery at almost any age, providing the pet is healthy. It is much better to perform a routine sterilization surgery on an older pet than to have to remove an infected uterus. Therefore, if any of your female pets have not been sterilized yet, you should discuss the sugary with our veterinarians.