Pyometra is a disease that
occurs mainly of middle-aged female dogs that have not been
spayed. In the past, we thought pyometra was simply a
uterine infection, but today, we know that it is a hormonal
abnormality, and a secondary bacterial infection. Pyometra
follows a heat cycle in which fertilization did not occur.
Typically, within two to four months after the cycle, the
female starts showing signs of the disease.
Cause of Pyometra
Cysts form in the lining of the uterus. These cysts contain
numerous secretory cells, and large quantities of fluids are
produced and released into the interior of the uterus.
This fluid, along with a
thickening of the walls of the uterus, brings about a
dramatic increase in the overall size of this organ. In the
unaffected dog or cat, the horns are smaller than a common
pencil. However, in cases of pyometra, they become large,
sac-like pouches the circumference of cucumbers and 12 to 18
As the disease continues,
fluid spills out of the vagina causing the animal to lick
this area in an attempt to keep itself clean. Bacteria
commonly colonize the uterus by entering through the cervix.
This produces an even greater response by the body, as it
showers additional fluid and white blood cells into the
After a while, the cervix
closes. This effectively traps all of the fluid within the
uterus. Still, the body continues to transfer more fluid and
white blood cells into the organ, causing even further
dilatation and growth. The uterus can rupture, spilling its
contents into the abdominal cavity. If this occurs, the dog
or cat usually dies in less than 48 hours. In most cases, it
is caught before this happens.
As the body attempts to
flush out the build-up of waste products through the
kidneys, the animal will drink excessive quantities of water
(polydipsia) and urinate large amounts frequently (polyuria).
She will lick at her vaginal area while the cervix is still
open and the uterus is discharging a white fluid. She may
run a low-grade fever and if blood work is done, she will
show an elevated white blood cell count. As the uterus
increases in size and weight, the dog shows weakness in the
rear legs, often to the point where she cannot rise without
help. If the dog enters kidney failure, she stops eating and
becomes very lethargic.
First line treatment may include antibiotics but this often
does not completely cure the problem. In most cases, the
preferred treatment is a complete
ovariohysterectomy (spay). This removes the ovaries,
oviducts, uterus, and all associated blood vessels. These
animals can be a surgical challenge because of their poor
The best prevention is to have all female animals spayed at
six months of age. If the animal is used for breeding, then
spaying the animal after she is past her breeding years is
Pyometra is a fairly common and serious problem and
is just one of many compelling reasons to have your female
pet spayed at an early age.