You might have heard of pyometra before; despite being common, it is one of the most deadly diseases that we vets come across.
What is Pyometra?
Pyometra literally means ‘pus in the uterus’. It occurs in about 25% of unspayed female dogs before the age of 10. In essence, pyometra is a uterine infection. It occurs because repeated cycles of oestrogen and progesterone, experienced by female dogs undergoing normal cycling, increases the thickening of the uterine wall. And, unlike humans, dogs don’t shed the lining of the uterus at the end of their season if they’re not pregnant. Instead, over time, the lining thickens, trapping fluid and mucus – sometimes called a mucometra. A mucometra is not dangerous, but if bacteria get into the uterus they find the perfect environment in which to replicate. A massive infection follows.
What are the Signs of Pyometra?
Pyometra almost always occurs relatively close to the end of the last season- usually 4-6 weeks after they stop bleeding. Dogs are usually three years or older, although pyometra has occasionally been diagnosed after just one season in some dogs. Affected dogs get gradually more ill: they may go off their food, become lethargic, or vomit. They often have an increase in thirst and urinate more than often as well. Owners may notice them licking at their back end more than normal.
Cloudy discharge from the vulva is sometimes apparent, but an absence doesn’t mean that pyometra isn’t possible – in fact, the more severe forms of pyometra occur when the cervix is closed, and the pus isn’t able to escape. Discharge can also be intermittent, or dogs can stop having discharge because the cervix closes – this is often seen as an improvement for many owners but is almost always followed by deterioration in their condition.
How is Pyometra Diagnosed?
In entire female dogs displaying symptoms at the right stage in their cycle, an ultrasound scan should always be performed. Ultrasound is easy to do and in well-behaved dogs usually allows a diagnosis without the need for anaesthetic or sedation. Vets will also need to examine the dog as a whole, take your dog’s temperature, and may recommend that blood tests are performed to check kidney and liver function.
How can Pyometra be Treated?
There are two options for treating pyometra. Surgery is usually recommended, as this is a permanent solution. The surgery is like a spay – the ovaries and uterus are removed through an incision in the abdomen. Unlike a normal spay, however, the uterus is heavier and full of pus, which could certainly kill the dog if any of it was to leak. This makes it a far riskier surgery than a normal spay.
Medical management is also possible. For this, dogs are given injections of an abortion agent, and antibiotics. This causes the body to stop the cycle and the infection will start to clear. Medical management is not always successful, and there is a high chance that the pyometra will reoccur on the next cycle. However, it sometimes saves a risky surgery and allows the uterus time to recover so that a spay can be planned for the usual window of opportunity between seasons.
Can pyometra be prevented?
Preventing pyometra is as simple as spaying dogs that are not going to be used for breeding. Without the ovaries constantly cycling from oestrogen to progesterone, the lining doesn’t build up and pyometra isn’t possible. In young dogs, the ovaries can be taken alone. The hormones won’t have had time to damage the uterine lining. As dogs age, however, a full ovariohysterectomy (ovaries and uterus removed) is often more sensible, as it leaves no risk of a later pyometra.
My dog has been spayed, can she still have a pyometra?
It’s technically possible for a dog to get pyometra after she has been spayed, in one very rare circumstance. Affected dogs usually suffer with Ovarian Remnant Syndrome. They have a small piece of ovary left behind after their spay. The cycle from that remnant can be enough to cause any remaining uterus to undergo the changes that lead to pyometra. This can lead to what is called a ‘stump pyometra’ . When the tiny bit of uterus that’s left behind because it’s attached to the cervix gets a pyometra.
Is Pyometra a Life or Death Situation?
Yes. Many cases of pyometra are severe enough that prompt treatment is the only thing that can save them. If you suspect your dog is suffering from pyometra, you should take your dog to have an examination with a vet immediately.