Asymptomatic bacteriuria in schoolgirls. III. Relation between residual urine volume and recurrence.

Residual urine volume (RUV) has been measured in 70 schoolgirls with asymptomatic bacteriuria using 121I-hippuran. The mean volume of residual urine was 23.7 ml. More than 5 ml RUV, the highest value found in 14 girls without bacteriuria or a history of urinary tract infection, was found in 47% of the patients. The mean volume for residual urine in the control girls was 1-1 ml. Among the 44 girls cured for their bacteriuria be a bladder wash out test or antibiotic treatment, recurrence was significantly more common (p less than 0.001) in those greater than 5 ml in RUV (45/20, 75%) than in those with less than or equal to 5 ml (4/24, 17%). In 5 of 22 patients not treated, the bacteriuria disappeared spontaneously during a one year observation period. The RUV was less than 3 ml in 4 of these 5 girls. While the presence of residual urine per se may not be the primary event leading to bacteriuria, it may increase the risk of recurrences, by facilitating bacterial growth and impairing the wash out of bacteria from the bladder on micturition.