Predictive Markers and Risk Factors in Canine Pyometra

Pyometra is a common and life-threatening disease in intact female dogs, which is generally treated by surgery. Early identification of dogs with high risk of complications or poor prognosis is valuable for optimising treatment and increase survival. The objectives of this thesis were to detect predictive markers for prognosis and outcome of pyometra by investigating clinical and pathophysiological responses and to explore the breed-dependent risk for pyometra and mammary tumours (MTs). Leucopaenia was the most important predictive variable, associated with an 18-fold increased risk for peritonitis (present in 13% of the dogs) and an over 3.5-fold increased risk for prolonged postoperative hospitalisation. Fever or hypothermia was linked with an increased risk for peritonitis and dogs with moderate to severely depressed general condition or pale mucous membranes had an increased risk for prolonged postoperative hospitalisation. These results show that commonly explored clinical variables may be helpful for predicting prognosis. Blood concentrations of the acute phase proteins, C-reactive protein and serum amyloid A (SAA) were found to be increased in dogs with pyometra, whereas concentrations of albumin, insulin-like growth factor-I, and iron were decreased. Importantly, SAA concentrations were higher in the dogs that also suffered from sepsis. Though unspecific, SAA could therefore be a potential marker for identifying more severely affected dogs. The neuroendocrine protein chromogranin A was measured by its breakdown products catestatin and vasostatin. Catestatin concentrations were decreased in pyometra whereas vasostatin concentrations did not differ compared to healthy dogs. None of these investigated inflammatory mediators or chromogranin A were useful for outcome prediction as measured by postoperative hospitalisation. The incidence of pyometra in 110 different breeds was studied using insurance data. Before 10 years of age, 19% of all female dogs had suffered from the disease. Breed greatly affected the risk of both pyometra and MTs. In summary, these findings show that clinical and laboratory data and analysis of inflammatory variables can be helpful for predicting prognosis and assessing severity in dogs with pyometra. Breed considerably affects the risk of pyometra and MTs, and the information presented in this thesis will be valuable for evaluating possible health benefits of spaying in individual dogs, based on the risk of developing these diseases.