Pyometra is a common disease in middle-aged to older female dogs that have not been spayed and, if the condition goes unnoticed for a week or two, the consequences can be disastrous. The development of sepsis and organ failure of kidney and liver, as well as the development of peritonitis and septic shock, can become irreversible. However, the condition can generally be treated.
Pyometra is defined by the accumulation of purulent fluid, or pus, in the uterus. Risk factors for the development of the disease are hormone treatment to abort unwanted pregnancies and phantom pregnancy.
Affected animals usually present with signs of lethargy, poor appetite, sometimes vomiting and very frequently, excessive drinking. Furthermore, the dogs often have vulvar discharge of a mucopurulent fluid and often history reveals that they were on heat three to four weeks previously. The vulvar discharge is not always present, however, because sometimes the cervix can stay closed, which in such cases is called closed pyometra.
The development of the disease revolves around the changes to the inner lining of the uterus (endometrium) to facilitate the growing conditions for a fertilised egg when the dog is in heat. The thickening and excessive growth (hyperplasia) of the endometrium leads to cyst formation and fluid production, and infection by bacteria can then take place via the cervix or the bloodstream.
Diagnosis is usually arrived at by a combination of diagnostic techniques, clinical examination and patient history. Palpation of the abdomen sometimes allows the clinician to feel the enlarged uterus, and x-rays and ultrasound in particular can confirm that the uterus is enlarged and fluid-filled. Complete blood cell counts will show an infection indicating leukogram in 75% of all cases and a diagnostic laboratory will give 100% certainty.
The most commonly pursued treatment option is the complete surgical removal of the uterus and ovaries (ovariohysterectomy). The severity of the dog’s clinical symptoms will determine the degree of stabilisation needed before surgery. Blood tests to determine liver and kidney damage, as well as blood clotting abilities of the dog, may be needed before proceeding with surgery. Intravenous fluid administration, together with a suitable antibiotic, helps with stabilisation before, during and after surgery.
The prognosis is generally good, as long as there is no sepsis, kidney or liver damage, under which circumstances the prognosis carries a higher risk.
The option of a purely medical treatment does also exist and it can be successful in young bitches, and owners who want to preserve the breeding potential of the dog often ask about it. Personally, I advise against this, because in my view it does not prioritise the welfare of the dog. Generally, the spaying of female dogs that are not intended for breeding or are retired from breeding is the best option to improve the quality of life for those animals.