The case fatality for pyometra overallwas 5.6%. In dogs it
is reported to be 3% to 4% [9]. The reason for the higher
fatality rate in cats is not known, but one theory could be
that this species is less sensitive to endotoxin, or not as
prone to show clinical signs unless they develop sepsis
[6,22]. In cats showing only mild signs of disease, admission
to a veterinary clinic relatively late in the disease progression
could potentially lead to a less favorable outcome [2].
This could also explainwhy many cats show only mild signs
of disease [2]. If the uterus ruptures, subsequent septic
bacterial peritonitis may lead to mortality rates up to 31% to
57%, which is why pyometra should be considered a serious
and potentially life-threatening condition