Pyometra is a disease affecting intact females. It is an abscessed, pus-filled infected uterus. Toxins and bacteria leak across the walls of the uterus and into the bloodstream, causing life-threatening toxic effects. Prevention of this disease is one of the main reasons for routinely spaying female dogs. Pyometra is a disease mainly in older female dogs usually following a heat cycle in which fertilization did not occur.
There are 2 classifications of pyometra. In the more usual “open pyometra,” the cervix is open and the purulent uterine contents are slowly expelled resulting in a smelly vaginal discharge. However, closed pyometra the cervix is closed and there is no vaginal discharge. The clinical presentation is more difficult to diagnose with closed pyometra. These patients also tend to be sicker than those with open pyometra because of the retained the toxic uterine contents.

Clinical signs
Clinical signs include a poor appetite and vomiting may occur. Patients will drink excessive amounts of water in attempts to flush the body of the toxins. A low grade fever may occur and blood work may reveal an elevated white blood cell count. Thick malodorous vaginal discharge may be apparent in cases of open pyometra. Radiographs may show a large distended uterus, but sometimes this is not obvious and ultrasound is needed to confirm the diagnosis.

The usual treatment is prompt surgical removal of the uterus and ovaries. It is crucial that the infected uterine contents do not spill and that no excess bleeding occurs. The surgery is challenging, especially if the patient is toxic and in poor condition. Antibiotics, IV fluids and pain relievers are given pre and post operatively. In some females valued for breeding, prostaglandin and antibiotic therapy may be tried instead of surgery. Hormones called prostaglandins are given for 5-7 days causing the uterus to contract and expel the fluid. This form of treatment is not an option in the event of a closed pyometra. Success is seen in mild cases, when the cervix is still open and the fluid is draining. This therapy should only be used in dogs 6 years of age or younger, who are in stable condition, and have an open cervix. Prostaglandins can have side effects, including restlessness, panting, vomiting, increased heart rate, fever, and defecation. There is a possibility of uterine rupture with the contractions resulting in peritonitis that escalates the life-threatening nature of the disease.

Spaying provides complete prevention for this condition. Spaying cannot be over-emphasized. Often an owner plans to breed a 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 assume that pyometra is highly likely to occur if the female pet is left unspayed.

Case of the month
Patient is a 9 year old female intact DSH presenting for inappetance and hiding. Patient was bright, alert and responsive on initial physical exam. Patient had a fever of 104 F and a large tubular like structure was palpated within then abdomen. Radiographs revealed 2 tubular structures within the caudal abdomen. An elevated white blood cell count was noted on blood work. The patient was diagnosed with a closed pyometra. The patient was started on antibiotics and IV fluids. Surgery was performed the following day to remove the enlarged uterus and ovaries. The patient recovered well postoperatively.