Difficulties in diagnosing urinary tract infections in small children

Urinary tract infections (UTIs) in children appear to be simple and straightforward matters, but there is as yet no consensus on UTIs in this patient group, and it remains one of the most - if not the most - controversial fields in paediatric medicine. Controversy and the lack of consensus can be found in many areas, including the diagnosis and management of UTIs in paediatric patients. Consequently, children with a UTI are investigated and treated quite differently in different parts of the world and also within different parts of the same country. One factor contributing to the current situation is the unexpected difficulty in diagnosing a UTI in children. This difficulty has implications not only for clinical work but also for scientific studies. Substantial over- and under-diagnosing can result from practical difficulties in at least three areas, including problems with collecting urine samples, in interpreting bacterial numbers correctly, and in confusing infantile asymptomatic bacteriuria and a true symptomatic febrile UTI. In this review, these problems will be discussed in detail as well as the implications they have had on clinical practice and research on UTIs.