Pyelonephritis is a urinary tract infection that starts in the bladder and travels up the ureters and into the kidneys. This infection can cause localized inflammation and pain as well as systemic symptoms. Pyelonephritis can be classified as either acute or chronic: 🚨Acute: Active bacterial infection that can cause inflammation, localized edema, tubular cell necrosis, and abscesses 🕰️ Chronic: Persistent, long-term kidney inflammation and scarring from recurrent acute infections or vesicouret