[The diagnosis and therapy of first community acquired urinary tract infection in children].
A first urinary tract infection (UTI) in childhood is more prevalent in females < 5-years-old. Circumcision generally protects males from UTI, however, during the month following the procedure, the prevalence of infection increases up to 12 times in circumcised boys when compared with those not circumcised. Almost all the infections are caused by aerobic Gram-negative bacteria of which E. coli are responsible for 70-90% of the cases. Signs and symptoms of UTI vary in different age groups. Factors associated with the likelihood of UTI are: non-circumcised male, fever > 40 degrees C, and a fever > 39 degrees C for more than 48 hours with no other focus of infection on physical examination. Urinalysis and urine microscopy are screening tests for UTI. In children with clinical symptoms and signs suggesting UTI, the results of these tests have a positive predictive value (if both are positive), or negative predictive value (if both are negative) approximating 100%. The definitive diagnosis of UTI is based on the urine culture. Bag urine culture is associated with a very high rate of contamination. Therefore, in non-toilet trained children, urine culture should be obtained directly from the urinary bladder either by supra pubic aspiration or in and out transurethral catheterization. Mid stream clean voided urine specimens obtained from circumcised males in the first months of life are also acceptable. Depending on the clinical presentation, oral therapy can begin from as early as two months of age, and the recommended empiric drugs for first febrile UTI are cefuroxime axetil, or amoxicillin clavulanate. Cephlexin is recommended for cystitis.