Pyometras, or uterine infections, are very common especially in older bitches due to the fact that (a) the immune system is weaker as they get older and (b) the hormone imbalances are even greater resulting in more dramatic changes. History of reproductive problems, abnormal reproductive cycles, the administration of hormonal therapy such as a mismate shot, etc. will all greatly increase the risk of a pyometra. These uterine infections are invariably related to the hormone changes associated with the metestrus part of the reproductive cycle which lasts for the two months after a heat. Every female dog regardless of whether or not she is pregnant goes through the same hormone changes during metestrus resulting in alterations to the uterus of which one of the most critical is suppression of the immune defenses in the uterus. This suppression occurs to facilitate implantation of the embryo but unfortunately it also acts to increase risk of infection. Of course, pregnant bitches have more dramatic alterations to the uterus but every bitch during this phase of the reproductive cycle has some basic alterations secondary to the hormone changes (primarily high progesterone and low estrogen).

Consequently, 3 to 6 weeks after a heat cycle a uterine infection often develops. If the cervix is open and the infection can drain oftentimes antibiotics and hormone therapy will clear the problem and it never becomes serious (b/c the discharge is noted and treatment sought). But if the cervix is closed then the uterus basically becomes one huge abscess filling up with pus. Initially no clinical signs are seen. Once the infection has reached such a massive amount that it "spills" over into the blood, the animal becomes very sick and this can rapidly become a life-threatening condition. Typically, signs are increased water intake, increased urination, lack of appetite, no energy, weak, etc. On examination the vet may or may not feel the uterus but bloodwork in dogs with a pyometra consistently shows massively high white blood cells. Radiographs will also help detect a pyometra. Surgical excision of the uterus (i.e. a spay) is the treatment of choice but surgical lavage with antibiotic and hormone therapy can sometimes be successful.

It is, therefore, advisable to spay any female dog that is no longer used breeding in particular those entering their senior years. Intact females should always be closely watched after a heat cycle for indicative signs of a pyometra. A pyometra in which the cervix is closed is considered a life-threatening emergency and should be treated as such.

For more information, please contact your veterinarian or email me..