Pyometra (or 'pyo') literally means 'pus in the womb' and is a potentially life-threatening condition that may occur in unspayed bitches. Following a season, between two weeks and two months, the bitch can develop an infection of the uterus and it fills with pus. There are two presentations of pyometra - open and closed.
The classic 'open' pyo scenario is where the bitch's cervix is open, allowing the pus being produced in the uterus to freely flow outside the body and therfore visible on examination. The less obvious, 'closed' pyo situation is where the cervix remains tightly closed, providing an effective seal capable of withholding the pus and making the condition slightly less obvious to diagnose. In either case, a thorough investigation will be required. With some pyometras, you will see some vulval discharge, and it will be quite a thick, creamy discharge, that will indicate an infection in the uterus. However, further on after the season, the cervix will close, and that pus will not be able to come out and show itself as a discharge.
Pyometra can present from the obvious: thick, brownish pus seeping from the bitch's vulva, to the much vaguer symptoms of being a bit quiet and perhaps just off her food. The reason for this wide spectrum of clinical signs is dependant on how long the pyo has been established and whether the pus has been able to drain out from the womb or not.
Some symptoms could be:
- noticeably increased thirst (polydipsia)
- spending most of her time licking an abnormal (and usually smelly) discharge from her lady bits
- swollen abdomen that is painful to touch
- turning her nose up at food - including her favourite treats
- greyish gums (depending how advanced the pyo is)
- vomiting and diarrhoea
- panting or restlessness
Pyometra can be caused by one or a combination of underlying factors. It can be the tiny, microscopic behaviour of the womb lining itself, likely hormonal imbalances. It can be a source of infection - usually 'ascending', meaning it enters the reproductive tract at the vulva from the outside world and creeps up, or comes via the blood stream from another infected area of the body. If the bitch has also recently given birth to a litter, an inflamed womb with bruised or exhausted and vulnerable tissues, can also act as a focus for infection to set in.
This is a veterinary emergency because if you do not get this treated there is potential for the uterus to rupture and the pus in the abdomen to cause peritonitis. This is life-threatening as the infection can be absorbed into the bloodstream and into the organs, potentially causing multi-organ failure.
Most bitches that have been spayed will not get pyometra. But, if your dog has only had part of her womb removed during neutering or part of the tissue has been left behind, this could become infected. This is called a ‘uterine stump pyometra’ and is very rare. Blue Cross, 2021