Pyelonephritis

Pyelonephritis is a bacterial infection that has ascended from the bladder into the kidney and its draining system (renal pelvis). It is a more severe form of urinary tract infection that can cause significant kidney damage, potentially leading to acute or chronic kidney disease if not treated effectively. Symptoms can include fever, lethargy, vomiting, back pain (especially over the kidney area), increased thirst and urination, and changes in appetite. Unlike simple bladder infections, pets with pyelonephritis often appear systemically ill. Diagnosis involves urinalysis, urine culture, and sometimes imaging. Treatment requires a prolonged course of antibiotics, often for several weeks, and close monitoring of kidney function.