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Medical Condition🐕 Dogs🐈 Catsreproductive

Pyometra

🗣️ Pronounced:pye-oh-MEE-truh
In One Sentence (Plain English)

A life-threatening bacterial infection and pus accumulation inside the uterus of intact female animals.

Editorial Status: Verified from peer-reviewed veterinary sources (v1.0)
Updated: 2026-01-15

💬 In Plain English

Pyometra is a severe, life-threatening infection of the uterus occurring in unspayed female dogs and cats, typically 2 to 8 weeks after their heat cycle. Under the influence of progesterone hormone, the uterine lining thickens and cysts form. Bacteria from the vagina ascend into the uterus, creating a massive pocket of pus. In “open” pyometra, foul-smelling discharge drains from the vulva. In “closed” pyometra, the cervix stays tightly shut, trapping the infection and toxins inside until the uterus risks rupturing.

🔬 Clinical & Technical Depth

For Vets & Technicians

Formal Clinical Definition

Progesterone-mediated cystic endometrial hyperplasia complicated by secondary bacterial infection (predominantly Escherichia coli), resulting in purulent intrauterine exudate accumulation and endotoxemia.

Why Veterinarians Use It

Veterinarians treat pyometra as a true surgical emergency due to the high risk of septic shock, uterine perforation, and acute renal failure.

Clinical Context Encountered

Seen in sexually intact female dogs and cats (especially middle-aged to senior animals) several weeks after their most recent estrus (heat) cycle.

Clinical Reference Guide (Medical Condition)

Severity
Emergency StatusNon-Emergency Care
🚨 Red Flag Warnings (When to Contact an Emergency Vet)
  • •Pyometra is a critical surgical emergency. Closed pyometra can cause uterine rupture, peritonitis, endotoxic shock, and death within hours if untreated.

❓ Questions to Ask Your Veterinarian

Take these actionable questions with you to your next clinic visit or appointment:

  • 1Is my pet’s pyometra open (draining) or closed (trapped)?
  • 2Are there signs of systemic sepsis or toxic kidney damage on her bloodwork?
  • 3How quickly can she be stabilized with IV fluids and antibiotics before emergency surgery?
  • 4Are the uterine walls intact, or has any leakage into the abdomen occurred?

Academic & Clinical References