Pyometra

Open vs closed pyometra

• Open pyometra, cervix is patent, purulent (often bloody) vaginal discharge is visible. Frequently caught earlier because the discharge is obvious.
• Closed pyometra, cervix is closed, pus is trapped inside the uterus, abdominal distension and rapid systemic deterioration follow. The dangerous form, diagnosis is harder, sepsis and uterine rupture risk is higher.

Clinical signs overlap with many other conditions: lethargy, decreased appetite, vomiting, polyuria/polydipsia, fever, and in closed cases an enlarging abdomen. Any intact female within ~8 weeks of a heat cycle showing these signs warrants immediate vet evaluation.

Treatment, surgical, urgent

The standard treatment is ovariohysterectomy, emergency spay, to remove the source of infection. This is performed on a far sicker patient than a routine spay, so anesthesia and surgical risk are elevated, but the alternative is a high mortality rate from sepsis and uterine rupture. Medical management with aglepristone (a progesterone antagonist) and antibiotics is possible in selected open cases where breeding preservation is essential, but recurrence rates are high and the patient must be stable.

Prevention

Spay/neuter eliminates the risk. Ovary-sparing spay (removing the uterus, leaving ovaries) also eliminates pyometra risk by removing the target organ, though it preserves heat-related behavior. Reported incidence in intact bitches by age 10 is in the range of 23–25% across multiple population studies, the single largest reason most veterinarians recommend spay if breeding is not intended.

Why it matters

Pyometra is the disease that turns the spay conversation from 'maybe, eventually' into 'soon'. Most owners do not learn what it is until their dog is on the surgery table for emergency repair. The mortality rate with prompt treatment is low; the mortality rate from delayed presentation is not.