Feline Pyometra

Pyometra is a bacterial infection of the uterus. The uterine lining gets thick and then infected by bacteria and filled with pus. Bacteria from the uterus can leak into the blood and abdomen, causing shock and death.

Pyometra is a life-threatening condition that requires quick and aggressive treatment.

Pyometra most commonly occurs in older, non-spayed, females following a heat cycle.

CAUSES:

With every heat cycle, the uterine walls thicken, preparing for pregnancy. If pregnancy does not occur after a few cycles, the following will cause infection:

• Cysts: will form in the thickening lining and produce fluids, a perfect environment for bacteria to grow
• Bacteria: enter the uterus from the vagina
• Thick uterine walls: prevent the uterus' muscles from squeezing together to push out the fluids and bacteria

During a heat cycle, white blood cells cannot enter the uterus. Therefore, when the bacteria grow, there is nothing to stop it.

Another cause can be reproductive medications that may contain hormones that cause the uterine wall to thicken. If your cat is not spayed and is on reproductive medicine, your veterinarian should monitor her.

SIGNS:

Signs depend if her cervix (the opening to the uterus) is open or closed.

Open cervix:

Foul-smelling vaginal discharge (blood, pus, or mucus) is the first sign of an infected uterus. You may see this discharge on your cat's skin, on the hair below the tail, or anywhere she has lain. These cats seem less sick because the infection can leave the body.

Keep in mind: many cats clean themselves of vaginal discharge before the owner sees it.

Closed cervix:

There will be no vaginal discharge. Instead, the infection leaks into the bloodstream and abdomen, leading to shock and death. These cats will be sicker than those with an open cervix because the infection stays in their body.

Common signs with a closed cervix:

• Lethargy and depression
• Loss of appetite
• Excessive drinking and urinating
• Vomiting
• Abdominal pain and swelling
• Continuous grooming at the vaginal opening

If you do not have your cat spayed, and she displays any of the above signs, go to your veterinarian right away. Pyometra is fatal without immediate treatment.

DIAGNOSIS:

To diagnose your cat with pyometra, your veterinarian may perform the following:

• Blood tests: animals with pyometra usually have a very high amount of white blood cells
• Urinalysis: animals with pyometra have a low urine concentration
• Culture analysis: study a sample of the vaginal discharge under a microscope
• Radiographs (in a case of a closed cervix): will show a swollen uterus with thick walls containing fluid
• Ultrasound (in the case of a closed cervix): will differentiate between a swollen uterus and pregnancy

TREATMENT:

Pyometra is life-threatening and needs aggressive treatment. The best treatment is an emergency spaying surgery, which is complicated because the infected contents of the uterus can spill.

The emergency spaying surgery includes:

• Complete removal of the ovaries and uterus to prevent future heat cycles and a recurrence of pyometra
• Hospitalization for a few days after the surgery
• IV fluids to stabilize the pet before and after surgery
• Antibiotics after surgery for any remaining infection

With an open cervix, and if the owner insists on preserving the animal's reproductive capability, your veterinarian may try treating the pyometra with hormone injections. These cause the uterus to contract and expel the pus. 

Medical treatment is dangerous because the contracting uterus can rip and spill puss. Its success rate is lower and leaves room for relapse. Also, your cat will not improve for about forty-eight hours, so it is not an option for severely ill cats.

Side effects last for a few hours after each injection and become milder with each treatment:

• Abdominal pain from the cramping
• Restlessness
• Panting
• Salivation
• Vomiting
• Defecation

PREVENTION:

Spaying your pet is a simple way to prevent a pyometra. Otherwise, your pet will eventually contract pyometra.

The importance of spaying cannot be stressed enough. A female pet will benefit from spaying at any age, but it's best to have your pet spayed at the youngest age possible.

PROGNOSIS:

Most pets will recover successfully with immediate surgery. However, if treatment is not performed promptly, pyometra is fatal because of the toxic effects of the pus.

This procedure is covered by pet insurance. Most vets will strongly suggest that you spay your cat. Once your cat is spayed, they will not be able to get a pyometra again as their uterus and ovaries have been removed. 

Medical Reviewed by Sara Redding Ochoa, DVM