Pyometra can be a tragic illness that is found in reproductively intact bitches. The condition can be a medical emergency, but knowing the risk factors and signs to look for can make early detection possible. The earlier pyometra is detected, the better the chance for successful treatment.
Symptoms: Pyometra is typically seen in middle-age bitches over the age of 6 years, but can happen as early as the first heat cycle. It usually occurs within 12 weeks after a heat cycle. Pyometra can occur in either a closed or open cervix. In a closed pyometra, the bitch will show signs of illness such as an increase in drinking and urinating, lethargy, vomiting, and abdominal distention. A closed pyometra is likely to cause more severe signs because of the retention of discharge, so it is important to get your dog to your veterinarian if you observe any symptoms. In an open pyometra, you may see bloodstained, thick vaginal discharge, but the bitch may not act as ill. Still, this can become a life threatening situation without proper veterinarian management
Causes: The complete cause is not fully understood, but does appear to be due to multiple factors. It is believed that the main cause is repeated exposure of the endometrium (the uterus lining) to high concentrations of estrogen during the heat cycle (estrus), followed by high concentrations of progesterone during diestrus (period following the heat cycle when the female is no longer receptive to the male).
This leads to the development of cystic endometrial hyperplasia, which occurs when the lining of the uterus thickens. If a bitch is not bred, the uterus lining continues to thicken, stimulated by the release of the progesterone and estrogen. The uterus lining can then form pockets where bacteria may develop and lead to pyometra. The bacterial infection is typically caused by E. coli that moves from the vagina through the cervix during estrus.
Diagnosis: To help diagnose pyometra, your veterinarian will likely run bloodwork to look for an elevation in white blood cells. A radiograph or the preferred method, an ultrasound, of the abdomen should also be performed. These tests will show an enlarged uterus if pyometra is present. Since pyometra can occur during the same time as pregnancy, pregnancy must be ruled out as the cause of an enlarged uterus.
Treatment: Pyometra can be treated surgically or with medication. The surgical treatment of spaying is the preferred treatment in all bitches not intended for breeding, those older than 4 years old that have chronic uterine changes, and those that are ill. Spaying is the only treatment that is guaranteed to prevent a pyometra from recurring.
Medical management with hospitalization, fluids, prostaglandins and the appropriate use of proper antibiotics can be tried in bitches that are still desired to be bred. If medical treatment is not successful after five days, spaying should be considered. If treatment does prove to be successful, the bitch should then be bred on her next heat cycle.