Pyometra
Let’s delve into Pyometra, a life-threatening disease that affects female dogs and cats who have not been spayed.
What is pyometra?
Pyometra is an extremely severe bacterial infection occurring within the uterus, leading to the accumulation of pus. It can develop in young dogs or cats, but it is more prevalent among older non-spayed female dogs who have never given birth. The increased bacterial presence in the uterus results in the production of endotoxins, triggering severe systemic inflammation. Consequently, this leads to dehydration, toxemia, kidney failure, liver failure, hypoglycemia, sepsis, and, in some instances, death. Pyometra manifests in two distinct forms: open cervix and closed cervix types. The cervix serves as the gateway to the uterus, with the closed cervix type generally causing more severe symptoms as pus becomes trapped within the body. If the uterus becomes engorged with pus, it can rupture, leading to peritonitis.
When and how does it occur?
In dogs, pyometra typically arises one to two months after their last estrus (heat cycle). This timing is associated with the prolonged secretion of a hormone known as progesterone during the estrous cycle. Progesterone contributes to the relaxation of the cervix (the uterine entrance) to facilitate sperm entry, thickens the uterine wall to enable sperm attachment, relaxes uterine muscles to prevent contractions, and lowers immunity levels. These factors create favorable conditions for bacteria to easily invade and proliferate in the uterus. The primary culprits are indigenous bacteria found around the anus or vulva, most commonly Escherichia coli.
How about cats?
Cats do not ovulate until they mate, unlike dogs, and therefore, they do not experience regularly recurring estrus cycles. This means that cats are less exposed to progesterone than dogs, resulting in a lower incidence of pyometra. However, it’s worth noting that spontaneous ovulation is now observed in approximately 40% of cats, warranting caution.
Symptoms
Common symptoms include a loss of appetite, fever, vomiting, increased drinking and urination, abdominal tension, and vaginal discharge.
Treatment
The optimal treatment is the removal of the ovaries and uterus, a procedure similar to spaying but with a higher risk profile. Given the rapid progression of this disease, surgery should be performed expeditiously. In cases where the animal’s condition is critical, fluid therapy and antibiotics are administered to address dehydration and sepsis prior to surgery. For internal treatment, hormone drugs can be employed to induce uterine contractions and expel pus. However, this internal treatment is not typically the initial choice, as it may not always succeed, and even if it does, there remains a significant risk of recurrence.
Prevention
Spaying at a young age is a 100% effective method to prevent pyometra. Additionally, it offers protection against the following conditions:
- ⚫ Tumors of the ovaries and uterus
- ⚫ Mammary gland tumors
・Prevention rates in dogs: Spaying before the first heat cycle: 99.5%, before the second heat cycle: 92%
・Prevention rate in cats: Spaying before 1 year old: 86%
* Ninety percent of mammary gland tumors in cats are malignant.
Early spaying also serves as a safeguard against mammary gland tumors. Remember, dogs and cats do not experience menopause.
