Pyometra
Pyometra is a serious, potentially life-threatening infection of the uterus that typically occurs in intact (unspayed) female dogs and cats during or after the progesterone-dominant phase of the estrous cycle. The progesterone-primed uterus becomes susceptible to bacterial infection, leading to pus accumulation. It can be open-cervix (draining) or closed-cervix (more dangerous).
Symptoms & Signs
- Vaginal discharge (open pyometra)
- Abdominal distension
- Increased thirst and urination
- Lethargy and depression
- Vomiting
- Loss of appetite
- Fever
- Collapse (if septic)
Causes & Risk Factors
Progesterone stimulation of the endometrium creates conditions favorable for bacterial growth (primarily E. coli). Cystic endometrial hyperplasia (CEH) predisposes to infection. Risk increases with age and number of estrous cycles without pregnancy. Exogenous progesterone/estrogen administration increases risk.
Diagnosis
History of recent heat cycle in intact female. Physical examination (vaginal discharge, enlarged uterus). Abdominal ultrasound showing fluid-filled uterine horns. Blood work: leukocytosis, elevated kidney values, azotemia.
Treatment
Ovariohysterectomy (spay) is the treatment of choice - curative and prevents recurrence. Medical management (prostaglandins, aglepristone) only for valuable breeding animals with open pyometra. Aggressive IV fluid therapy and antibiotics for stabilization.
Prevention
Spaying (ovariohysterectomy) eliminates risk completely. If breeding, breed on consecutive cycles rather than skipping. Avoid exogenous hormone administration. Monitor intact females closely after heat cycles.
Prognosis
Excellent with timely surgical intervention. Closed pyometra without treatment: fatal (uterine rupture, sepsis). Medical management: 20-25% recurrence rate. Post-surgical recovery typically rapid.