Easy to cause urinary tract infection in children
Physiological characteristics: for baby use diapers, urethral mouth is often affected by fecal pollution, plus local defense ability is poor, easy cause ascending infection, especially in girls with urethral short. The baby body antibacterial ability is poor, prone to bacteremia can result in descending infection.
Congenital malformation and urinary tract obstruction: the former is more common as adult ureteropelvic junction stenosis, renal pelvis seeper, posterior urethral valve, polycystic kidney disease can make poor drainage and secondary infection. Also can be caused by neurogenic bladder calculi, obstruction, tumor etc.. In a medical center with deformity of urethra can be accounted for the total urinary tract infection in 25% ~ 50%.
Vesicoureteric reflux (referred to as reflux): infant common. Introduction of foreign patients with urinary tract infection in children under 10 years old, 35% ~ 60% with reflux, but the number of cases reported in China is very few, still needs further observation. Under normal circumstances, there is a walk of ureter in the bladder wall, when filling and voiding bladder urine, bladder wall pressure the catheter to close, the urine can not return flow. In infancy, the bladder wall walking ureteral short, shut not complete due to reflux many children micturition. Bacterial with reflux ascending infection. The harm that urine reflux reflux nephropathy and renal scarring, occur in children less than 5 years old. Reflux and renal scarring is proportional to. Mild reflux may disappear with age, but severe reflux need operation treatment. Therefore, the children find out there is no regurgitation on diagnosis has important significance in guiding treatment of urinary tract infection.
Pathogenic bacteria of 80% ~ 90% by intestinal bacteria pathogenic. In case the first primary disease, the most common is Escherichia coli, followed by Proteus, Klebsiella and Escherichia coli. A few fecal streptococcus and Staphylococcus aureus, even caused by viruses, protozoa and fungi. More than 90% of acute pyelonephritis Escherichia coli isolated from children is p umbrella strains, and that the adhesion of the P umbrella is microbial uplink. Treatment is not complete or with urinary tract abnormalities, bacterial resistance, can cause repeated infection, persistent unhealed, turn for chronic. Sometimes due to the role of antibiotics, the bacteria to produce variable mutation, cell membrane rupture, can not maintain the original state, but still in the medulla of the kidney in hypertonic environment to survive, such as premature discontinuation of treatment, the bacteria can cause restitution. And the bacteria in the general medium without growth, growth only in hypertonic medium, have nutrition, so to chronic pyelonephritis can not see for the improvement of clinical symptoms, and repeated negative urine culture, should also be hypertonic culture, specific pathogens.
The route of infection of ascending infection is more common in girls; ② hematogenous infection in neonates and small infants, common in impetigo, pneumonia, sepsis course; the minority by the lymphatic pathway and adjacent organ or tissue caused by direct spread; the urinary apparatus examination can also horse as the route of infection.