Pyelonephritis is defined as a severe bacterial infection of the kidney proper, specifically affecting the renal pelvis and the functional tissue known as the parenchyma. Unlike a simple bladder infection, this condition triggers a profound inflammatory response deep within the organ. It is a frequent but often hidden complication in cats with Chronic Kidney Disease. In these patients, bacteria ascend from the bladder into the kidneys because the dilute urine of a CKD cat lacks natural antibacterial properties. This active inflammation destroys nephrons and can trigger an Acute Kidney Injury crisis where kidney values spike suddenly. Diagnosis requires a Urine Culture and Sensitivity because standard tests often miss the bacteria in watery urine. Additionally, ultrasound may reveal pyelectasia, which is a dilation or swelling of the kidney's drainage system. Treatment typically involves a long course of antibiotics chosen based on culture results to penetrate the inflamed tissue and eradicate the infection.
Disclaimer: This content is for educational purposes only and does not constitute veterinary medical advice. Always consult with your primary care veterinarian or a veterinary internal medicine specialist regarding your cat’s specific condition.