the white blood cell count may be normal, possibly because the white blood cells are sequestered in the uterus. There may be changes in the urine if toxins released by the bacteria affect the kidneys. This is also what causes increased drinking and urination. Radiographs (X-rays) may reveal the presence of an abnormal enlarged fluid-filled uterus in a bitch that is not pregnant or in early pregnancy. In mid-pregnancy, it is not too easy to distinguish between a uterus filled with pus and a uterus filled with pups. Only in very late pregnancy do the puppies' bones become calcified enough to show up on an X-ray. Ultrasound is a much better diagnostic tool. It can determine the presence of pyometra at any stage of pregnancy. In some cases, swabbing the vagina and making a smear to look for white blood cells or culturing for bacteria may be helpful.
Ingle & Mead's Vizsla -- Pyometra in the Bitch
Canine pyometra is a diestrual disease typical of adult intact bitches whose development is strongly influenced by sequential progestational stimulations (normal diestrus or treatment with progestins) of the uterus. Bitches whelping rarely or never in their lives have a greater chance of developing pyometra with rare or no occurrence of pregnancy. For unknown reasons gestation has a protective action on the canine endometrium, causing pyometra not to develop in areas of the endometrium where placental attachment has occurred (although pyometra can occur in one horn with pregnancy in the opposite horn). During a progestational stimulation the canine endometrium proliferates and starts secreting the so called "uterine milk" while the cervix remains closed and myometrial contractility is inhibited (Table n° 1) . Fluid accumulates into the endometrial glands which then dilate becoming fairly large (up to 0.3-2.0 cm diameter). The endometrial pattern that develops is referred to as cystic endometrial hyperplasia (CEH) which is a prerequisite for the development of pyometra due to the fact that the uterine milk in itself constitutes an inflammatory stimulus as well as an excellent culture media for bacteria which. CEH is a physiological phenomenon whose regression starts during the second half of diestrus. However, with time and number of "open" (non-pregnant) cycles CEH may not entirely disappear from some sections of the endometrium, thus increasing chances of causing endometrial inflammation. Fecal/perineal bacteria (E. coli, Streptococcus spp., Staphylococcus spp., Klebsiella, Proteus and Pseudomonas are the most common ones) often concur to the development of uterine lesions and clinical signs (especially if they cannot be cleared from the uterus prior to onset of the luteal phase), but are not necessary for the clinical manifestation of the disease. E. coli can produce an endotoxin which, upon bacterial death (i.e., following an antibiotic treatment), is released into the uterine lumen and absorbed. The resulting endotoxemia may cause a severe shock reaction and death of the bitch depending on the amount of endotoxin released and on the physical condition of the dog (antibiotics have no effect on concentrations of endotoxins). Clinical signs of endotoxemia include disorientation, hypothermia and shock.
Canine Pyometra - WSAVA 2002
Pyometra and pregnancy can coexist. I would be nervous with the elevated WBC. Did the vet see any thickening of the uterine lining indicating Cystic Endometrial Hyperplasia (the chance that happens before pyometra)?
If it is thought to be pyo, I don't see how she can finish the pregnancy safety. You may want to talk to a veterinarian who specializes in reproduction because it seems that your female could be in danger...