What is a normal post-void residue (PVR) for a 10-year-old child?

Normal Post-Void Residual Urine Volume for a 10-Year-Old Child

For a 10-year-old child, a normal post-void residual (PVR) urine volume should be less than 20 ml. 1

Understanding Post-Void Residual in Children

• PVR is an important parameter in evaluating lower urinary tract function in children and should be measured as part of the assessment of voiding dysfunction 2
• Due to significant intra-individual variability, a single PVR test is not reliable for assessing pediatric voiding function; two PVR tests are recommended 1
• PVR measurement should be repeated up to 3 times in the same setting in a well-hydrated child to ensure reliable results 2
• Ultrasound is the preferred non-invasive method for determining PVR in children 3

Normal PVR Values by Age

• For children around 10 years old, a PVR greater than 20 ml on repeated measurements (without bladder over-distention) is considered abnormal 1
• Median PVR values in healthy children are approximately:
  • 5.5 ml at age 1 year 4
  • 0 ml at age 3 years 4
  • 2 ml at age 6 years 4
• PVR increases with age and varies by gender, with higher values typically seen in older adolescents and females 5

Factors Affecting PVR Measurement

• Bladder over-distention (defined as bladder capacity ≥115% of expected capacity) can artificially increase PVR values 1
• PVR increases as bladder capacity increases (r = 0.38, p <0.01) 1
• Drinking large amounts of fluid before voiding can lead to bladder over-distention and affect PVR measurements 1
• PVR tends to decrease as children age (when excluding those with bladder over-distention) 1

Clinical Implications of Elevated PVR

• Elevated PVR is a significant risk factor for urinary tract infections and can predict treatment outcomes in various pediatric urological conditions 5
• In children with dysfunctional voiding, double voiding (several toilet visits in close succession) may be recommended to improve bladder emptying, particularly in the morning and at night 6
• Treatment results should be monitored with regular voiding charts, uroflowmetry, and measurement of PVR 6

Associated Conditions

• Constipation can significantly affect PVR; studies show that in children with increased PVR and constipation, 66% experienced improved bladder emptying after constipation treatment alone 7
• Constipation treatment led to resolution of daytime wetting in 89% and nighttime wetting in 63% of cases, as well as prevention of urinary tract infections 6
• Always assess for bowel dysfunction in children with elevated PVR, as the two conditions are frequently related 7

Common Pitfalls in PVR Assessment

• Relying on a single PVR measurement can lead to misdiagnosis due to significant intra-individual variability 1
• Not considering bladder over-distention when interpreting PVR values can lead to false positives 1
• Failing to evaluate associated conditions like constipation that may contribute to elevated PVR can lead to incomplete management 7
• Using adult PVR cutoff values for children is inappropriate as normal values vary significantly by age 5