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Pyometra is defined as a 'pus filled uterus', and means quite simply a uterine infection. These types of infections seem to be fairly common in female rats possibly because it is not common practice to spay rats like it is for dogs and cats, and so the occurance will naturally be higher in unspayed animals.

As pyometra involves the uterus, or womb, it can only occur in females. It is impossible for a male to suffer this condition.

There are two types of pyometra:
- Open pyometra.
- Closed pyometra.

The difference between the two types is simple. In open pyometra, the cervix is open, in closed pyometra it is closed.

The symptoms you will initially notice are a swollen abdomen, and most noticeably, bleeding from the vagina in open pyometra. The pus and blood caused by the infection builds up and is able to leave the uterus and leak from the vagina if the cervix is open. It may be possible to cause blood to emerge by pressing on the swollen abdomen, though I can't imagine this is particularly pleasant for the rat. The start of the infection will involve inflammation of the lining of the uterine wall. This inflammation in effect causes all the cells in the lining to burst, and this is what causes the vaginal bleeding.

In closed pyometra this will not happen. The blood and pus is not able to leave the uterus. Instead the infection will build up, causing abdominal swelling and absorption of the infection into the bloodstream, resulting in toxicity and eventually death.

In dogs it is reported that you may notice greater water consumption than usual, loss of appetite, and vomiting. Rats are physically incapable of vomiting, but you may notice loss of appetite, or general signs of feeling under the weather, such as a fluffed up coat, lethargy, and dull eyes in the later stages of the condition.

Rats with pyometra may also experience uterine cramps. These are particularly painful and will involve a heaving motion of the abdomen. It is possible to confuse these cramps with breathing difficulties that rats so often suffer.

Untreated pyometra is fatal.

It is therefore vitally important that you provide immediate veterinary treatment for your rat. Initially it is wise to start a course of broad spectrum antibiotics.

It is not unknown for antibiotics to clear up the infection entirely, providing they are dosed properly, and the infection was not too serious. However, pyometra can recur. Whether or not it actually does before the rat comes to the end of her natural life will logically depend on her age and fitness at first occurance. The only guaranteed cure and prevention from reoccurance is for a veterinary surgeon to perform an ovariohysterectomy - a complete surgical removal of the ovaries and uterus, more commonly known as a spay.

This procedure is not without risk, though at the time of writing the survival rate for pyometra rats I have known undergo this operation is 100% success. All cases have not only survived the operation, but thrived afterwards.

Having said that, a pyometra spay is not the same as a routine spay, and the surgeon must take care not to let any pus leak into the body cavity during surgery, as this can have dire consequences. It requires a skilled veterinarian who is confident in his or her ability to perform the surgery. It can be an expensive operation, but in many cases it is the only option and the surgery is performed in order to save the rats life. Naturally, this procedure renders the rat utterly infertile, which can also have its benefits.

The first days after the spay the rat will experience some unpleasant abdominal cramps. This is why the spay is the only operation where it is generally recommended to give your rat some pain relief afterwards. Different types of analgesics can be suitable, depending on your vets choice, but a common choice is Meloxicam (brand name Metacam).

For further reading on post operative care, please see this article.

Interestingly, I recently came across an article about pyometra on a dog breeders website. The suggested treatment of open pyometra for brood bitches was a high dose of antibiotics and injections of prostaglandin twice daily. The prostaglandin is intended to cause severe uterine contractions to force out the pus. The dog in question would need to be walked for 30 minutes after receiving the prostaglandin injection to 'ease' the treatment. At the risk of sounding like I'm putting too much of my own opinion into this, this treatment sounds quite a brutal treatment to put an animal through with no guarantee it'll even work, just for the sake of salvaging her uterus so that she can be bred from again.

Written by Laura, amended by Joolz.


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