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Pyometra in Dogs - Causes, Treatment and Prevention

What is Pyometra:
Pyometra is a common disease in female dogs.
The term "pyometra" refers to a potential y fatal condition in which the uterus becomes infected and
gradually fil s with pus. Many dog owners are unaware of this disease, yet veterinary professionals know
the signs al too wel : behavioural changes including lethargy, increased thirst, increased urination and
loss of appetite are amongst the earliest symptoms. As the infection festers, abdominal bloating and/or
oozing discharge from the vulva may be noticeable. Without prompt veterinary attention, your dog
could quickly deteriorate and die from infection or a rupture of the uterine wal s.
Animals which can be affected:
Older, intact female dogs that are one to two months beyond estrus (being in heat) are at high risk for
pyometra. Intact females of all ages that receive progesterone or estrogen hormones for estrus
synchronization or mismating are also at risk. Spayed animals are rarely affected.
Causes of Pyometra:
Pyometra develops after bacteria infiltrate the uterus through the cervix, which opens during the heat
cycle and fol owing pregnancy. Escherichia coli is the most common bacteria identified in pyometra.
Whenever levels of the reproductive hormone progesterone rise, the uterine lining becomes susceptible
to bacterial infection.
Symptoms:
Common symptoms include foul or bloody discharge from the vulva, loss of appetite, inactivity, fever,
depression, and increased water consumption and urination. The abdomen frequently enlarges.
Severely affected animals may show signs of blood poisoning, with pale mucous membranes, cold
extremities, reduced body temperature, vomiting or collapse. The presence of vaginal discharge is
variable.
Types of Pyometra:
Closed - this is an extremely dangerous condition in which the closure of the cervix causes pus to pool
in the uterus with no escape. As this happens your dog may become increasingly "off" and her
symptoms may worsen over a short period of time. Because there is no discharge and other symptoms
of infection aren't easily noticeable, owners may decide to wait it out before seeking veterinary
attention. Unfortunately, this increases the risk that uterus wil continuously expand and eventual y
rupture within the body, or that the kidneys wil fail. Up to 1/3 of pyometra victims wil fal into this
category.
Open - this type of pyometra occurs when the cervix remains open fol owing infection. There wil
usually be tell-tale discharge around the vulva, however this can easily be mistaken as a continuation of
the heat cycle. Though the uterus may not swel or expand, an open pyometra is stil classed as an
emergency due to the threat of organ damage - especial y to the kidneys. The sooner your pet receives
veterinary attention the better the prognosis wil be.
Stump - though rare, a stump pyometra is dangerous in that it is often unexpected: it occurs in spayed
animals. Unbeknownst to many owners, stump infections may occur in remnants of tissue left behind
during a routine spay, which fil with infected fluid. The symptoms and risks are similar to those of a
true pyometra, therefore it is important that owners of spayed pets consult their vet as soon as any of
the previously-mentioned symptoms crop up.
The severity of the resulting il ness is greatly influenced by the degree of drainage from the uterus. If
the cervix is closed, then fluids and toxins accumulate, like an abscess, with potential for toxic effects.
Rupture or slow leakage from one of the uterine horns can release inflammatory products into the
abdominal cavity, causing peritonitis. If the cervix is patent, or open, then drainage limits the
accumulation of inflammatory products and bacterial toxins, and increases the likelihood of early
recognition of the problem. Signs of increased thirst and urination have been linked to the direct
influence of bacterial toxins on the kidneys’ urine concentrating mechanisms.
Bacterial infection and toxins may cause secondary damage to the liver as wel . Endotoxic shock alters
blood supply to all tissues and can disrupt normal blood clotting mechanisms. Microscopic blood clots or
clumps of circulating bacteria can further impact upon the blood supply to vital organs such as the heart
and brain, permitting seizures, cardiac rhythm disturbances and other grave consequences.
Clinical Signs:
Signs of pyometra usual y appear between one to two months after the female is in heat, or after the
hormone progesterone has been administered. Common symptoms include vaginal discharge, anorexia,
lethargy, pyrexia, depression, polyuria, and polydipsia. Some dogs remain asymptomatic except for a
thick, vaginal discharge. This discharge is usual y purulent, or pus containing, but may occasional y be
mixed with blood.
Physical examination reveals abdominal distention, an enlarged, palpable uterus, vaginal discharge if
the cervix is open, and lethargy. A closed-cervix pyometra more likely wil result in the animal showing
signs of septicemia, including shock, hypothermia, dehydration, vomiting, and col apse.
Treatment:
The most common form of treatment for pyometra is an emergency ovariohysterectomy or spay,
meaning that the veterinary surgeon wil remove the ovaries and uterus to prevent the latter from
rupturing. Before a positive diagnosis is made, your vet wil need to examine your bitch to determine
whether the cervix is open or closed, as wel as how advanced the infection has become. The condition
of your pet wil determine the next step. In some instances, your vet will make the diagnosis just by
feeling the dog's uterus through her abdomen, but ultrasound and x-ray may also be used. Sometimes
blood tests wil be run in order to confirm the presence of white blood cells - a hallmark of infection. If
the infection is caught early enough it may be possible to treat it medically with antibiotics. In severe
cases, the patient wil go straight to the operating prep room post-diagnosis, day or night. A successful
spay at this phase is not synonymous with survival: advanced infection may damage the vital organs to
the extent that they never recover. Therefore, your vet wil take necessary precautions to ensure that
your pet is protected from the effects of the anaesthetic agents and surgery itself.
Prognosis:
Prognosis following ovariohysterectomy, or spay, is good if there is no uterine rupture or other source
of contamination. Mortality is less than 10 percent. If there is gross contamination of the abdomen,
then open peritoneal drainage is indicated. These patients wil certainly be hospitalized for longer
periods of time, with a need for intensive care. The prognosis for such patients is guarded.
Dogs with an open cervix that are treated medical y with prostaglandin general y have a good response
to treatment, with complete resolution of infection in 75 to 90 percent of cases. In contrast, only 25 to
30 percent of dogs with closed cervix pyometra demonstrate complete resolution of signs. The majority
of patients wil require a second series of injections. Unfortunately, recurrence is common. Perhaps 80
percent of dogs treated medically wil have a recurrence of pyometra. Ovariohysterectomy is then
advised.
Prevention:
An elective ovariohysterectomy of the young dog wil virtual y eliminate the possibility of pyometra.
Avoidance of estrogen or progesterone administration wil decrease the risk of pyometra in both young
and mature pets.
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Source: http://www.dominionbullmastiffclub.co.nz/.cm4all/iproc.php/Pyometra%20in%20Dogs.pdf?cdp=a