Urinary tract infection, routine urine examination will appear elevated white blood cells. Because urine contains pathogenic bacteria, then the body’s leukocytes will converge to the urine to phagocytosis of pathogenic bacteria, play a role in eliminating pathogenic bacteria, so in the examination of urine can appear leukocyte elevation, bacteriocin elevation and other manifestations. However, mild urinary tract infection has not yet caused further systemic toxicity symptoms, so at this time will not be accompanied by blood leukocyte elevation, only manifested as a mild urinary tract irritation symptoms, not accompanied by chills, fever and other symptoms. Further aggravation of the infection can cause systemic symptoms of toxicity, resulting in elevated white blood cells in the blood, which are commonly accompanied by fever, which may be preceded by chills and fever. If further aggravation of the infection causes sepsis, or even infectious shock in severe cases, it will cause the patient’s blood pressure to drop and vital signs to gradually decline.