Pyelonephritis, also known as upper urinary tract infection, is an inflammatory reaction caused by bacterial infection of the urinary system. Therefore, in cases of recurrence of this condition, it is still necessary to use antibiotics for bactericidal treatment, generally requiring a full two-week course, choosing drugs with low nephrotoxicity. Additionally, it is important to investigate whether there are any complicating factors for pyelonephritis, such as the presence of diabetes, urinary system stones, tumors, or urinary tract anomalies. Identifying and addressing these complicating factors can reduce the likelihood of recurrence of pyelonephritis.