Understanding Pyometra in Cats: Causes, Symptoms, and Prevention
Pyometra is a potentially life-threatening uterine infection that can affect unspayed female cats. This condition is most common in older females but can occur at any age in intact cats. Understanding what causes pyometra can help pet owners recognize early signs and seek immediate veterinary care for their feline companions.
What Causes Pyometra in Cats?
Pyometra is primarily caused by hormonal influences that affect the uterus of intact female cats during their reproductive cycles. After estrus (heat), the cat's body produces the hormone progesterone. This prepares the uterus for potential pregnancy by thickening the uterine lining and suppressing immune responses. Over repeated cycles, these changes create an environment conducive to bacterial growth, especially when there is no pregnancy.
Bacteria enter the uterus through the cervix, which is temporarily open during estrus. Once the cervix closes after estrus, the trapped bacteria can proliferate, leading to infection and accumulation of pus within the uterus. The most common causative organism is
Escherichia coli (E. coli), though other bacteria like Staphylococcus, Streptococcus, or Pasteurella spp. may be involved.
Predisposing Factors
- Repeated hormonal cycles without pregnancy
- Advanced age in intact females (more than 5 years old)
- Use of hormone-based drugs such as progesterone or estrogen
- Structural abnormalities or history of uterine infections
Types of Pyometra
There are two main forms of pyometra:
- Open Pyometra: The cervix is open, allowing pus to drain from the uterus through the vulva. Signs include foul-smelling discharge, constant licking of the genital area, and visible soiling around the tail.
- Closed Pyometra: More dangerous and harder to detect; the cervix is closed, so pus remains inside the uterus. This can lead to rapid systemic illness, sepsis, and death if untreated.
Clinical Signs of Pyometra
- Lethargy
- Loss of appetite
- Fever
- Vomiting or diarrhea
- Increased thirst and urination
- Abdominal swelling or pain
- Purulent vaginal discharge (in open pyometra)
Diagnosis
Veterinarians use a combination of history, physical examination, and diagnostic tests:
- Bloodwork: Indicates infection, often showing elevated white blood cells and increased globulins.
- Ultrasound or Radiographs: Visualizes an enlarged, fluid-filled uterus.
- Vaginal cytology: May help confirm presence of infection if discharge is available.
Treatment Options
The treatment of choice for pyometra is
emergency ovariohysterectomy (spaying)—removal of the uterus and ovaries. This not only resolves the infection but also prevents recurrence. In some cases, where surgery is high-risk,
medical management may be considered:
- Prostaglandins: Help expel uterine contents (mostly used in dogs, less effective in cats)
- Antibiotics: Broad-spectrum administration for infection control
- Supportive care: IV fluids, pain management, and hospitalization
However, medical therapy carries a high risk of recurrence and should only be an option under strict veterinary supervision.
Prevention
The only guaranteed prevention strategy is
spaying your female cat. Benefits of spaying include:
- Eliminates risk of pyometra
- Prevents unwanted litters
- Reduces risk of mammary cancer if done early
Prognosis
With
early diagnosis and prompt treatment, especially surgical intervention, the prognosis for pyometra is good. However, delays in treatment—especially with closed pyometra—can lead to septic shock, organ failure, and death.
Final Thoughts
Pyometra is a serious but preventable condition in cats. By understanding its causes, signs, and treatment options, pet owners can better protect their companions. Spaying remains the most effective solution to avoid this potentially fatal disease. Always consult with your veterinarian if your cat shows abnormal symptoms, especially during or after her heat cycle.
