Canine pyometra, also called chronic purulent endometritis, is a common reproductive disorder, which affects nearly one fourth of all female dogs before they reach ten years of age. The disease is characterised by chronic uterine inflammation with bacterial growth of Escherichia coli (E. coli). The disease is often seen in countries where routine spaying of young dogs is not common practice. According to a study performed on over 200,000 dogs by Swedish researchers, the occurrence of pyometra differs with age, breed, and geographic location.

The risk of developing pyometra is increased in the Rough Collie, Rottweiler, Cavalier King Charles Spaniel, Golden Retriever, Bernese Mountain Dog, and English Cocker Spaniel. This disease is known to lead to systemic inflammation, potentially affecting multiple organs in the body, including the heart. Despite modern treatment therapies, the mortality rate due to pyometra is about 4%. Myocardial injury due to the endotoxemia (presence of endotoxins in the blood), inflammation, disseminated bacterial infection and necrosis of heart muscle, is suspected to be a contributing factor to unexpected deaths in female dogs.5

Canine pyometra has two forms. In open pyometra, the cervix is open, and the smelly vaginal discharge is the most obvious sign. In closed pyometra, there is no vaginal discharge, making diagnosis more difficult. Of the two forms, the closed pyometra is more serious, since dogs become toxic from the unreleased urine contents and may develop substantial kidney damage. Early on, before any discharge becomes apparent, the signs of pyometra mimic those of many other ailments, including poor appetite, vomiting and increased thirst, and even toxic shock syndrome. Once diagnosed via laboratory tests, X-rays or ultrasound, the next step is removal of the dog's uterus and ovaries, the safest and most satisfactory treatment of pyometra. Anesthesia and surgery may cause serious heart complications with subsequent myocardial cell damage, especially in dogs with systemic inflammation and impaired circulation. Thus, heart muscle injury is a potential cause of increased mortality in dogs with pyometra before, during and after surgery.

Rottweiler puppy running
Rottweilers are predisposed to pyometra


  1. Concentrations of cardiac Troponin I before and after ovariohysterectomy in 46 female dogs with pyometra. Lena Pelander, Ragnvi Hagman and Jens Häggström
  2. Caring for Your Aging Dog By Janice Borzendowski
  3. Breed risk of pyometra in insured dogs in Sweden. Egenvall A, Hagman R, Bonnett BN, Hedhammar A, Olson P, Lagerstedt AS.
  4. Blood lactate levels in 31 female dogs with pyometra
  5. Cardiac troponin I levels in canine pyometra
  6. Pyometra in Bitches Induces Elevated Plasma Endotoxin and Prostaglandin F2α Metabolite Levels

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