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Pyometra is an accumulation of pus within the uterus
accompanied by hperplastic changes in the uterine mucosa.

A very
enlarged uterus, filled with pus


This condition most frequently is encountered in bitches
over 5 years of age. The disease is attributed to ovarian
dysfunction with increased progesterone secretion. Factors
associated with occurrence of pyometra include
administration of longlasting progestational compounds to
delay or suppress estrus, administration of estrogens to
mismated bitches, and postinsemination or postcopulation

The contents of the affected uterus may be sterile though
in some cases there is a gross bacterial contamination.

The organisms most commonly found are Escherichia coli and

Most evidence suggests metritis to be most commonly a
bacterial infection while pyometra appears to be of
endocrine origin. Pyometra is less common in cats and can
remain asymptomatic for long periods.


Anorexia is usually the first sign, followed by depression,
lack of appetite, polydipsia (drinking excessive amounts of
water) and polyuria. Vomiting frequently follows drinking
and the animal will drink and then vomit as long as water
is provided. At this stage, the respiratory rate is
increased and the temperature may be elevated, but, as the
condition progresses, the temperature falls and finally
becomes subnormal.

Progressive weakness develops and eventually the animal is
unable to stand. The abdomen is distended and pain may be
manifested on palpation.

Pyometra can be a life threatening infection and may even
require emergency surgery. A closed pyometra is more of an
emergency than an open pyometra, since there is no drainage
of pus in a closed pyometra. If the pet has closed pyometra
the cervix is not open and pus cannot drain to the outside.
If an open pyometra is present, the pus can drain through
the cervix. Discharges often have a characteristic
‘sickly-sweet’ odor and small quantities may accumulate on
the hair around the vulva and on the tail.

The vulva is often enlarged and occasionally a persistent
diarrhea accompanies the disease.

Neglected or untreated animals commonly die.


The distended uterine horns are easily detected by

Radiographic confirmation is a simple procedure and is
taken to look for a fluid filled uterus, which is
suggestive of a pyometra

Blood tests are often submitted to look for abnormal white
cell counts, which could indicate the presence of an

An abdominal ultrasound is made to look for a fluid filled
uterus and also to rule out an early pregnancy.

Nany animals with pyometra also have renal failure and its
associated biochemical changes.These findings, together
with a history of nonpregnancy and the clinical signs,
point to fairly positive diagnosis. A salient point in the
history is the occurence of signs 2-8 weeks after estrus.


Ovariohysterctomy should be undertaken
as soon as the electrolyte and fluid imbalance is
corrected. Medical management could
be considered if salvaging t
he reproductive
potential of the bitch or queen is desired. The
bacterial infection is responsible for the illness and
will not resolve until the uterine exudate is removed.
Antibiotics should be administered, also after
surgery. Pain relievers are often needed

If excess fluid losses occur such as polyuria, vomiting or
diarrhea, additional fluids should be given.

After surgery all patients should be monitored for signs of
renal failure

Spaying represents complete prevention for this
condition. Spaying cannot be over-emphasized. Often an
owner plans to breed their pet or is undecided, time
passes, and then they fear she is too old to be spayed. The
female dog or cat can benefit from spaying at any age. The
best approach is to figure that pyometra will eventually
occur if the female pet is left unspayed; any perceived
risks of surgery are very much out-weighed by the risk of