Characteristics of the bladder in infants with urinary tract infections: an ultrasound study.

BACKGROUND: Patients with urinary tract infection (UTI) are known to have impaired bladder function as demonstrated by urodynamic (UD) studies. UD is rarely performed in infants. OBJECTIVE: To evaluate bladder function in infants with UTI using a dynamic US protocol. Maximal bladder volume (MaxBV), residual volume (RV) and bladder wall thickness (BWT) were measured and compared with values from normal controls. MATERIALS AND METHODS: A total of 57 consecutive infants (47 males, 10 females; mean age 0.48+/-0.30 years) with proven UTI, and 63 age-matched normal controls (37 males, 26 females; mean age 0.47+/-0.37 years) were recruited. MaxBV was determined just before voiding, and RV and BWT were measured after spontaneous voiding. RESULTS: Infants with UTI had smaller MaxBV (34.89 vs. 42.91 ml), larger RV (3.46 vs. 1.51 ml) and greater BWT (4.21 vs. 3.68 mm) than normal infants (P<0.05, Mann-Whitney test). CONCLUSION: Smaller bladder volume, larger residual volume and thicker bladder wall in infants with UTI can be explained by bladder instability, hypercontractility and infection-induced oedema of the bladder wall during UTI. The US measurement of bladder parameters might serve as an objective guide for clinical diagnosis and allow objective evaluation of bladder function during posttreatment follow-up.