Pyometra
At Foothills Animal Hospital we are strong advocates of spaying female dogs and cats as young animals. However, even in older intact females spaying can prevent the development of two serious conditions related to the uterus. Pyometria and cystic endometrial hyperplasia are very common in older female that continue to "cycle". This is particularly true in those female that are not successfully producing puppies or kittens. We probably see about 20 intact female each year with mild or serious pyometria and more with endometrial hyperplasia. When a dog develops pyometria we are force to perform the "spay" under the worst possible condition for what would otherwise have been a routine proceedure.
Pyometra is a disease mainly of middle-aged female dogs and cats that have not been spayed. In the past it was thought that pyometra was simply a uterine infection, but today it is knows that it is a hormonal abnormality, and a secondary bacterial infection may or may not be present. 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.
The two main hormones produced by the ovaries are estrogen and progesterone. An excessive quantity of progesterone, or the uterus becoming oversensitive to it, causes pyometra. In either case, 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. The uterus is made up of a body with two horns. 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 inches long. Normally the entire uterus in a 40-pound dog will weigh two to four ounces, but in cases of pyometra this typically ranges from one to four pounds.
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 affected organ.
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 this does not happen.
The body will attempt to eliminate the problem by carrying the wastes and excess fluid through the bloodstream to the kidneys. However, the amount of material in a dog with pyometra is too great to be eliminated in this fashion, overloading the kidney system. The normal toxins that should be excreted from the body build up, and the animal goes into uremic poisoning. Untreated, she will die from kidney failure.
Symptoms
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. As the dog enters kidney failure,
she stops eating and becomes very lethargic
Treatment
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 overall condition. Most of these patients are kept
on intravenous fluids and antibiotics for several days. In some
females valued for breeding, hormonal and antibiotic therapy may
be tried instead of surgery. In mild cases this is sometimes effective
but many times the animal doesn't respond well and ultimately
has an ovariohysterectomy performed.
Prevention
The best prevention is to have all female animals spayed at or
before six months of age. If the animal is used for breeding,
then spaying the animal after she is past her breeding years is
highly recommended. 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.
Question and answer
What are pyometra and cystic endometrial hyperplasia?
Pyometra and cystic endometrial hyperplasia are problems of
the uterus. Pyometra is the medical
term for accumulation of pus in the uterine cavity. It can develop
secondarily to cystic endometrial
hyperplasia when bacteria invade the abnormal uterine lining.
Cystic endometrial hyperplasia is a
progressive change of the lining of the uterus. It is a response
to female hormones.
What causes pyometra and cystic endometrial hyperplasia?
Pyometra and cystic endometrial hyperplasia are caused as a
result of the action of female
hormones, estrogen and progesterone. In dogs, repeated exposure
to estrogen followed by
exposure to progesterone may initiate changes in the uterine lining,
leading to cystic endometrial
hyperplasia and then pyometra. In cats, the changes may be caused
by estrogen during heat
(estrus) followed by a progesterone phase caused by induction
of ovulation.
What are the signs of pyometra or cystic endometrial hyperplasia?
The signs of pyometra or cystic endometrial hyperplasia vary.
In cases of pyometra, the animal will be sicker if the cervix
is closed than if the cervix is open, allowing drainage. Clinical
signs that may be seen include vaginal discharge, depression,
lethargy, poor appetite, excessive thirst
(polydipsia), and excessive urination (polyuria). The animal may
vomit or may have an enlarged
abdomen. A fever may or may not be present. The veterinarian may
be able to feel (palpate) an
enlarged uterus; however, if the cervix is open, the uterus may
not be enlarged.
How are pyometra and cystic endometrial hyperplasia diagnosed?
Pyometra and cystic endometrial hyperplasia are diagnosed by
medical history (recent heat cycle)
and physical examination. Physical examination findings are very
important in the diagnosis of
these conditions. Some laboratory tests (blood tests and urinalysis)
are helpful, but do not provide
a definitive diagnosis. Animals with pyometra generally have elevated
white blood cell counts.
Radiographs (X-rays) can be used to detect a large uterus and
to rule out pregnancy, if necessary. In pets with pyometra, the
uterus may be enlarged or distended. Ultrasound (visualization
of deep body tissues by recording ultrasonic waves) can be used
to assess the size of the uterus, the extent of cystic endometrial
hyperplasia, and to rule out pregnancy. The normal uterine wall
is not visible with ultrasound; pyometra and cystic endometrial
hyperplasia are associated with a thickened uterine wall and the
presence of fluid in the uterine cavity.
How are pyometra and cystic endometrial hyperplasia treated?
Pyometra is a life-threatening condition, if the cervix is
closed. Animals should be hospitalized and
supportive care with the administration of fluids and antibiotics
begun immediately. The preferred treatment for pyometra and
cystic endometrial hyperplasia is ovariohysterectomy (spay).
Medical treatment of closed-cervix pyometra is associated with
rupture of the uterus and peritonitis. These are serious complications.
Medical treatment probably does not cure underlying cystic endometrial
hyperplasia in patients with pyometra.
What is the prognosis for animals with pyometra or cystic endometrial hyperplasia?
The prognosis (outcome) for animals with pyometra or cystic
endometrial hyperplasia varies. An
animal with pyometra treated by ovariohysterectomy (spay) that
does not have serious
complications (such as rupture of the uterus, generalized infection,
or shock) has a good
prognosis. An animal with pyometra and serious complications has
a guarded to poor prognosis.
An animal with cystic endometrial hyperplasia, uncomplicated by
pyometra that undergoes
ovariohysterectomy has an excellent prognosis.
The majority of the information in this page is has been taken from VetMedCenter.com. For further information about this useful source of informtion follow the link or look, on the internet, at www.vetmedcenter.com.