What is a pyometra?
A pyometra is a bacterial infection of the uterus due to hormonal action, causing the uterus to fill with pus. This is a very serious, potentially life-threatening condition if left untreated.
The word pyometra is derived from the Latin “pyo”, meaning pus, and “metra”, meaning uterus or womb.
It can occur in any intact female cat and dog of any age but is most common in middle-aged and older intact females.
The most common time for a pyometra to develop is 4-8 weeks after a heat cycle.
Following an estrus (heat) cycle, progesterone levels remain high for 8-10 weeks, thickening the lining of the uterus in preparation for pregnancy. If pregnancy does not occur for several estrus cycles, the uterine lining continues to increase in thickness until cysts form within it, a condition called cystic endometrial hyperplasia. The thickened, cystic uterine tissue creates an ideal environment for bacteria to grow.
How do bacteria enter the uterus?
The cervix is the gateway to the uterus, a small cannel that connects the uterus to the vagina. It normally remains tightly closed, except during estrus, when it relaxes to allow for sperm to enter the uterus. When the cervix is open, bacteria that is normally found in the vaginal canal or introduced by the male during mating can enter the uterus.
A thickened, cystic uterine lining prevents normal uterine defense mechanisms from functioning optimally, creating an ideal environment for bacterial growth. A pyometra develops as the uterus fills with pus.
What are the symptoms?
Symptoms can depend on whether the cervix is open or closed.
When the cervix is open (referred to as an open pyometra) the pus that accumulates in the uterus can drain through the vagina to the outside.
This abnormal, smelly discharge is often noticeable on the fur around the vulva or on bedding where the pet has laid. Cats are very cleanly creatures and will most likely clean the discharge before the pet owner notices.
Because the pus is able to drain from the uterus the pet is usually not as sick as in the case of a closed pyometra, however, fever, lethargy and inappetence may be noticed.
When the cervix is closed (referred to as a closed pyometra) the pus is not able to drain from the uterus, causing uterine distention. The toxins released by the bacteria spread into the bloodstream causing rapid, severe illness.
A pet suffering from a closed pyometra is very lethargic, has a fever and is inappetent.
In both an open and closed pyometra, the toxins released by the bacteria can affect the kidney’s ability to regulate the body’s fluid balance. This causes the pet to drink an excess amount of water and urinate more often. Bacteria from the infected uterus can spread through the bloodstream, affecting various organs, including the kidneys. Kidney failure is a possible complication in pets diagnosed with pyometra.
How is a pyometra diagnosed?
A diagnosis of pyometra is reached when a veterinarian collects information form the owner (also called history-taking) and evaluates the patient’s clinical signs.
Diagnostic procedures such as the evaluation of a bloods mear and vaginal discharge under the microscope, as well as an abdominal ultrasound will provide valuable information to reach a final diagnosis and stage the severity of the condition.
How is a pyometra treated?
Panhystorectomy is the treatment of choice and involves the surgical removal of the entire uterus, fallopian tubes and ovaries. The procedure is more complicated than a routine spay as the pet is very ill, the uterus is enlarged and fragile and full of pus. Intravenous fluids will be required before, during and after surgery along with antibiotics and pain medication. Hospitalisation after surgery may be required to facilitate the necessary after care.
What is likely to happen if left untreated?
Pets that are seen early in the course of the disease may have a slight vaginal discharge and show no other signs of illness. However, most pets with a pyometra are not seen until they have become very ill.
The chances of recovery without surgery are extremely low. If surgery is not performed timely, a pyometra may be fatal. A closed pyometra can rupture spilling the infected uterine contents into the abdominal cavity. Fatal septic shot and death is inevitable.
Spaying of female pets prevents pyometra!
