Pyelonephritis is an upper urinary tract infection. When the condition recurs, the initial symptoms are similar. Patients may also experience fever, and the temperature can rise quickly, even up to 40 degrees Celsius. There may also be a systemic inflammatory response, characterized by fatigue and loss of appetite, among other symptoms. Recurrence can also cause pain in the lumbar region, which may even radiate to the perineal area, and patients may also experience visible hematuria. In urinalysis, leukocytes or positive leukocyte esterase can be observed. These are the symptoms of recurring pyelonephritis.