The typical symptom of acute urinary tract infection is urinary tract irritation, which is the triad of urinary tract irritation with frequency, urgency and painful urination. For example, in acute infections of the lower urinary tract, in addition to the typical symptoms of urinary tract irritation, there are also symptoms such as hematuria or burning sensation in the urethra, but fever or chills rarely occur; for upper urinary tract infections, such as acute pyelonephritis, in addition to the typical symptoms of urinary tract irritation, patients often also have fever and chills. Patients’ tend to have fever and chills as well, and the temperature is relatively high when fever is present, and can reach more than 39 degrees or even 40 degrees in severe cases. This is accompanied by headache, nausea, vomiting and other symptoms. Some patients may also experience back pain on the infected side, which may be manifested as a distinct painful percussion on one side of the kidney.