Date Published: May 4, 2007
Publisher: BioMed Central
Author(s): Reidun Heiene, Veronica Kristiansen, Jon Teige, Johan Høgset Jansen.
Age-related changes in renal histomorphology are described, while the presence of glomerulonephritis in dogs with pyometra is controversial in current literature.
Dogs with pyometra were examined retrospectively for evidence of secondary renal damage and persisting renal disease through two retrospective studies. In Study 1, light microscopic lesions of renal tissue were graded and compared in nineteen dogs with pyometra and thirteen age-matched control bitches. In Study 2, forty-one owners of dogs with pyometra were interviewed approximately 8 years after surgery for evidence ofclinical signs of renal failure in order to document causes of death/euthanasia.
Interstitial inflammation and tubular atrophy were more pronounced in dogs with pyometra than in the control animals. Glomerular lesions classified as glomerular sclerosis were present in both groups. No unequivocal light microscopic features of glomerulonephritis were observed in bitches in any of the groups.
Tubulointerstitial inflammation was observed, but glomerular damage beyond age-related changes could not be demonstrated by light microscopy in the dogs with pyometra. However, severe proteinuria after surgery may predispose to development of renal failure.
In both human  and veterinary nephrology [2,3]., proteinuria has been shown to contribute substantially to the development of end stage renal disease. Clinical intervention by drug therapy is indicated to protect renal function .
The most prominent morphological difference between two groups was the interstitial inflammatory infiltrates prevalent in dogs with pyometra. These plasma-lymphocytic interstitial infiltrates, often with a periglomerular location, were accompanied by a higher prevalence of interstitial fibrosis and tubular atrophy in dogs with pyometra (Figures 1 and 3). These observations are in accordance with previous reports of renal lesions in dogs with pyometra .
histopathological examination and evaluation revealed tubular and interstitial lesions in dogs with pyometra, but histological features specific for glomeruonephritis were not prominent. Glomerular sclerosis was prevalent in dogs with pyometra and in control dogs. The questionnaire did not reveal clinical signs of kidney disease after surgery in most dogs with pyometra; although PU/PD was observed in five dogs and two dogs died from renal disease.
The author(s) declare that they have no competing interests.