Pyometra is infection of the uterus (womb) in dogs or cats. These
infections tend to occur between four and ten weeks after being
in season (estrus). Where the cervix remains open a discharge
will be seen from the vulva. This can vary from a red-brown to
yellow colour. Closed cervix pyometra represents a more serious
and more difficult to diagnose condition. The uterus fills with
purulent material (infection), swelling sometimes to an extreme
size, even to the point of rupturing. As the infection develops
other signs including depression, dehydration, loss of appetite,
excessive drinking and urinating (polydypsia and polyuria), vomiting
and diarrhea. In closed pyometra enlargement of the abdomen may
eventually be noticed. The rectal temperature is generally normal.
Blood tests may show and increase in the inflammatory white blood
cells (leukocytes) with greater numbers of immature cells released
from the bone marrow (left shift), and damaged cells (toxic neutrophils),
which all indicate infection. Pyometra can be easily mistaken
for pregnancy with the swelling of the abdomen where the cervix
remains closed. Xrays can be used to detect the presence of fetuses
from 6 weeks into pregnancy, however prior to this there is no
radiographic difference between pyometra and pregnancy. Ultrasound
is more accurate in distinguishing between the two conditions.
The treatment of choice for pyometra is removal of the uterus
and ovaries (ovariohysterectomy). As the animals are often toxic
and dehydrated they must be initially stabilized with intravenous
fluids (drip) and antibiotics. It may be possible to treat a discharging
pyometra without removing the uterus using antibiotics and prostaglandin
(PGF2a). The prostaglandins cause contraction of the uterus and
are given as a three to five day course. Antibiotics are chosen
on the basis of laboratory testing of the discharge (culture and
sensitivity) and are administered for two to four weeks. This
treatment should only be used in valuable breeding animals as
there are short term side effects of prostaglandins and recurrences
can occur.
