Pyometra

What is it?

Pyometra is a bacterial infection of the uterus driven by hormone changes after heat. Prolonged high progesterone thickens the uterine lining and can form cysts that make an ideal place for bacteria. It can affect any unspayed female but is most common in older cats. Hormone medications containing progesterone or estrogen can also raise the risk.

What signs should I watch for?

If the cervix is open, pus (often bloody) drains from the vulva and may be seen on the fur or bedding. If it is closed, pus builds up, the belly may swell, and cats can become very ill quickly. Other signs include lethargy, poor appetite, vomiting, and drinking and urinating more. Signs can progress rapidly to shock and death.

How is it diagnosed and treated?

Diagnosis uses an exam, the nature of any discharge, X-rays, ultrasound, and blood and urine tests. Spaying (removing the uterus and ovaries) is the best treatment in most cases and is curative; the cat may need intravenous fluids and antibiotics first. Medical treatment with prostaglandins may be considered for some breeding cats with an open cervix, but it has side effects, carries a risk of uterine rupture (higher with a closed cervix), and recurrence is common.

Can it be prevented, and what's the outlook?

• Without treatment, pyometra is often fatal.
• Any unspayed female given hormones should be watched closely.
• Cats that respond to medical treatment should be bred on following cycles until no more litters are wanted, then spayed.