Urinary tract infections, commonly known as urinary tract infections, are inflammatory conditions caused by the direct invasion of bacteria into the urinary tract. The infection can involve the upper and lower urinary tracts and is collectively referred to as urinary tract infection because of the difficulty in localizing it. Clinically, it is divided into acute and chronic. The former has an acute onset, and the symptoms are more typical and easy to diagnose, but the symptoms are not typical in infancy, and the diagnosis is difficult. Chronic and repeated infections can lead to kidney damage. Repeated infections in pediatrics are often accompanied by structural abnormalities of the urinary tract, and the cause should be carefully investigated to relieve congenital obstruction and prevent kidney damage and scar formation. Urinary tract infection is a common disease in pediatrics, which is mainly caused by Escherichia coli, followed by varroa, aerobacteria, paracolon, and a few are caused by Staphylococcus aureus. This disease is often confused with gynecological inflammation, need to be treated with caution. Etiology More than 95% of urinary tract infections are caused by a single bacterium. 90% of outpatients and about 50% of hospitalized patients, the pathogen is Escherichia coli, the bacteria serotypes up to 140 species, causing urinary sensation type Escherichia coli and the patient fecal isolation of Escherichia coli belongs to a type of bacterial, most often seen in asymptomatic bacteriuria or uncomplicated urinary sensation; Aspergillus, Bacillus aeruginosa, Klebsiella pneumophila, Pseudomonas aeruginosa, Streptococcus faecalis, and so on. Reinfection, indwelling catheter, there are complications of urinary tract infection; Candida albicans, new cryptococcal infections in diabetes mellitus and the use of glucocorticoids and immunosuppressive drugs in patients and renal transplantation; Staphylococcus aureus is often seen in the skin trauma and drug addicts caused by bacteremia and sepsis; viruses, mycoplasma infections, although rare, in recent years, there is a gradual increase in tendency. A variety of bacterial infections are seen in indwelling catheters, neurogenic bladder, stones, congenital malformations and vaginal, intestinal, urethral fistula. Clinical manifestations 1, acute simple cystitis: sudden onset, the onset of female patients are mostly related to sexual activity. The main manifestations are bladder irritation, that is, urinary frequency, urinary urgency, urinary pain, bladder area or perineum discomfort and urethral burning sensation; urinary frequency varies in degree, severe cases can appear incontinence of urgency; urine turbidity, urine with leukocytes, common terminal hematuria, and sometimes the whole process of hematuria, and even see the blood clots discharged. Generally, there is no obvious systemic infection symptoms, and the body temperature is normal or low fever. 2, acute simple pyelonephritis (1) urinary symptoms include urinary frequency, urgency, urinary pain and other signs of bladder irritation; hematuria; the affected side or bilateral lumbago; the affected side of the spinal cord angle has obvious pressure or percussion pain, etc.; (2) systemic infections, such as chills, high fever, headache, nausea, vomiting, loss of appetite, etc., often accompanied by elevated blood leukocyte counts and increased sedimentation rate. 3, asymptomatic bacteriuria: asymptomatic bacteriuria is a kind of hidden urinary tract infection, mostly seen in elderly women and pregnant women, the patient does not have any symptoms of urinary tract infection, the incidence rate increases with age. 4, complex urinary tract infection: complex urinary tract infection clinical manifestations vary greatly, often accompanied by other diseases that increase the risk of acquiring infections or treatment failure, may or may not be accompanied by clinical symptoms (such as urinary frequency, urgency, urinary pain, urination difficulties, low back pain, spinal rib angle pressure, suprapubic pain and fever, etc.). Complicated urinary tract infections are often accompanied by other diseases, such as diabetes mellitus and renal failure; they also lead to a greater number of sequelae, the most serious and fatal of which include urinary sepsis and renal failure, which can be categorized as acute and chronic, reversible and irreversible.