Answers and Discussion--Pyometritis

emtitle.jpg (59025 bytes)

Answers and Discussion

Case #6-- Pyometritis

Describe why ultrasound is important in the diagnosis of pyometritis.
The dog may be pregnant. Radiographs will only show an enlarged uterus in the first two trimesters. Ultrasonography is the best tool for distinguishing the contents of the uterus.
Describe why "Maggie" was polydipsic and polyuric with pyometritis.
Approximately 50% of dogs with pyometritis present with polyuria/polydipsia. These renal manifestations are poorly understood but may result from prerenal azotemia secondary to dehydration and/or shock; antigen-antibody complex glomerulonephropathy; endotoxin interference with renal tubular function (renal diabetes insipidus); or a combination of the above.
Describe what emergency treatments you would institute for "Maggie".
Begin IV fluids immediately. Also give an intravenous, broad-spectrum, bactericidal antibiotic. Continue the antibiotics until culture and sensitivity results are returned. Take "Maggie" to surgery if the owner will allow.

Describe when you should perform surgery?
As soon as possible!!! Surgery should be performed within the first 6-12 hours of treatment, even sooner if the uterus is thought to have ruptured.

pyosurg.jpg (95115 bytes)
Pyometritis seen at surgery. The tissue is extremely friable and care must be taken in removing the uterus.

List and explain the medical alternative to surgery.
Prostaglandin F2-alpha and long-term, broad-spectrum antibiotics can be used to treat open-cervix pyometras. This treatment should be reserved for stable bitches who will be bred during the next heat cycle. If you must treat a closed-cervix pyometra medically, do so cautiously because of the great risk of the uterus rupturing. Lutalyse (a natural PGF2-alpha) is the drug of choice and given at a dose of 0.05-0.25 mg/kg SQ once or twice a day for 3-5 days. It stimulates uterine motility, forcing the uterine contents through the cervix, thus explaining why it is so dangerous to use with a closed-cervix pyometra. Side effects include panting, salivation, vomiting, defecation and micturition. However, these effects usually disappear after the first hour of treatment and subsequent injections result in less severe signs.

Explain the prognosis for pyometritis?
Prognosis is good for those patients treated with surgery. It is also good for those treated medically for open-cervix pyometras, with a >90% recovery rate. It is highly recommended that these animals be bred during the next heat cycle, since >70% of bitches successfully treated with PGF2-alpha redevelop pyometritis within 2 years. Prognosis is poor for patients treated medically for closed-cervix pyometras. Fewer than 30% recover when treated with prostaglandins.

Follow-Up: "Maggie's" recovery from surgery was uneventful and her signs resolved following the ovariohysterectomy.

***Pyometritis Pearls***
Pyometritis is a life-threatening emergency and surgery should be performed as soon as possible. Before initiating treatment, ultrasonography should be used to determine if the dog might be pregnant. Before surgery, initiate shock fluids and broad-spectrum, bactericidal antibiotics.