What is pyometra?
Pyometra is as an infection in the uterus as a result of a secondary infection due to hormonal changes in the female during “heat”. It is a serious and life threatening condition that must be treated quickly and aggressively in both dogs and cats. When a female undergoes “heat” her body suppresses her local immune system so as not to destroy a male’s sperm. After “heat” her progesterone levels (pregnancy hormone) remain elevated for up to two months and cause thickening of the lining of the uterus for pregnancy and fetal development. If pregnancy does not occur after several heat cycles, the uterine lining will increase in thickness until cysts form (a condition called Cystic Endometrial Hyperplasia). The thickened, cystic lining secretes fluids that create a perfect environment for bacteria to grow in. Additionally, high progesterone levels inhibit uterine contraction to expel accumulated fluids or bacteria. The combination of these factors often leads to infection.
How do bacteria get into the uterus?
The cervix acts as a protective barrier for the uterus and remains tightly closed except during “heat”, when it opens to allow sperm to enter. If the cervix is open, bacteria that are normally found in the vagina can enter the uterus easily.
When does pyometra occur?
Pyometra may occur in any sexually intact young to middle-aged animals; however, it is most common in older females. Pyometra usually occurs two to eight weeks after the last estrus (“heat cycle”). Dogs and cats do not undergo menopause.
What are the clinical signs of pyometra?
The clinical signs depend on whether or not the cervix remains open. If it is open, pus will drain from the uterus through the vagina to the outside. An abnormal discharge is often seen on the skin or hair under the tail or on bedding and furniture where the pet has recently laid. Fever, lethargy, anorexia, and depression may or may not be present.
If the cervix is closed, pus that forms is not able to drain to the outside. It collects in the uterus causing the abdomen to distend. The bacteria release toxins that are absorbed into the bloodstream. Dogs with closed pyometra become severely ill very rapidly. They are anorectic, very listless and very depressed. Vomiting or diarrhea may also be present.
Toxins released by the bacteria affect the kidney’s and many animals drink an excess of water to compensate. Increased water consumption may occur in both open- and closed pyometra.
How is pyometra diagnosed?
Dogs that are examined early in the course of the disease may have a slight vaginal discharge and show no other signs of illness. A very ill female dog with a history of recent “heat” that is drinking an increased amount of water should be suspected of having pyometra. This is especially true if there is a vaginal discharge or a painful, enlarged abdomen.
If the cervix is closed, radiographs of the abdomen will often identify the enlarged uterus. If the cervix is open, there will often be such minimal uterine enlargement that the radiograph will be inconclusive. An ultrasound examination may be helpful in identifying an enlarged uterus and differentiating that from a normal pregnancy.
How is pyometra treated?
The preferred treatment is to surgically remove the infected uterus and ovaries, or perform an spay. Animals diagnosed in the early stage of the disease are very good surgical candidates. However, most animals are diagnosed with pyometra when they are quite ill resulting in a more complicated surgical procedure and a longer period of hospitalization. Intravenous fluids are required to stabilize the patient before and after surgery. Antibiotics are usually given for two weeks after surgery. There is a medical approach to treating pyometra, although the success rate is widely variable and not without considerable risk and potential long-term complications.
Success rates for medical management
1. The success rate for treating open-cervix pyometra is approximately 75-90% in uncomplicated cases.
2. The success rate for treating closed-cervix pyometra is only about 25-40%.
3. The rate of recurrence of the disease in a treated dog is generally thought to be as high as 50-75%.
4. The chance of future successful breeding is decreased to about 50-75 in dogs%.
What happens if I don’t treat?
If treatment is not performed quickly, the toxic effects from the bacteria will be fatal in many cases. If the cervix is closed, it is possible for the uterus to rupture, spilling the infection into the abdominal cavity. This will also be fatal.
Pyometra is a serious medical condition that requires immediate treatment, if you think your dog or cat has a pyometra or are looking to have your dog spayed to prevent pyometra contact Meadowlands Veterinary Hospital at 201-646-2008