EN
Pyonephritis - a purulent inflammation of the kidney is a serious disease often leading to death of animal, particularly when both kidneys are affected. In the present case a three years old cow on day 5th postpartum suffered from bilateral nephritis. The illness was diagnosed by the clinical examination and rectal sonography. Because of bad prognosis, the cow was slaughtered. Several liters of fluid were found in the peritoneal and pleural cavities. The kidneys were enlarged with plum-size yellow-cream pork fat-like changes under the capsule. Massive inflammatory changes in the renal cortex and medulla with granulomas were observed microscopically. The histological structure of the organ was weakly defined. Only few glomerules were visible. There were large necrotic areas with neutrophil infiltration and aggregations of bacteria in the interstitial tissue. Non-haemolytic E. coli and Clostridium sp. were identified bacteriologically from the urine and renal tissue. The pyelonephritis ascendens purulenta et granulomatosa was diagnosed finally.