136
Development and Assessment of
Lower Urinary Tract Function in
Children
Chung Kwong Yeung; Stephen Shei-Dei Yang; Piet Hoebeke
Questions
1.Development of normal bladder function involves which of the following changes?
a.Decrease in urine production and increase in bladder capacity
b.Increase in urine production and increase in voiding frequency
c.Increase in bladder capacity and decrease in voiding frequency
d.Decrease in voided volume and increase in voiding frequency
e.Increase in bladder capacity and no change in voided volume
2.Which of the following statements best describes urodynamic findings of maximum detrusor pressures with micturition (Pdetmax) in young infants with
normal lower urinary tracts?
a.There is no difference in Pdetmax compared with that in adults.
b.Lower Pdetmax is observed in young infants compared with adults.
c.Higher Pdetmax is observed in male infants only.
d.Higher Pdetmax is observed in female infants only.
e.Higher Pdetmax is observed in both male and female infants.
3.Which of the following statements on neurologic control of normal micturition is INCORRECT?
a.Innervation of the bladder involves both the central somatic and the autonomic nervous system.
b.Micturition is initiated with a full bladder by a simple spinal cord reflex.
c.Micturition does not occur during sleep.
d.Development of direct volitional control over the bladder-sphincter complex occurs.
e.Neurologic control occurs at different levels of the central nervous system from spinal cord to brainstem.
4.The following is characteristic of children with urge syndrome:
a.Vincent's curtsy sign.
b.hold maneuver.
c.urgency.
d.small bladder capacity.
e.all of the above.
5.Regarding normal parameters of lower urinary tract function, which statement is INCORRECT?
a.Low bladder compliance (less than 20 mL H2O) is frequently
associated with neuropathic lower urinary tract dysfunction (LUTD) and may have detrimental effects on the upper tracts.
b.The International Children's Continence Society (ICCS) views 6 years as the minimum age to adequately report lower urinary tract symptoms, and 5 years as the minimum age for functional bowel dysfunction.
c.ICCS defines increased daytime urinary frequency as eight or more voids per day and decreased daytime urinary frequency as three or fewer voids per day.
d.Bladder outlet obstruction can be suspected in cases with a Qmax less than 11.5 mL/sec (patients aged 4 to 6 years) or less than 15.0 mL/sec (patients aged 7 to 12 years).
e.For children aged 4 to 6 years, repetitive postvoid residual (PVR) greater than 20 mL or greater than 10% bladder capacity (BC) can be regarded as elevated. For children aged 7 to 12 years, repetitive PVR greater than 10 mL or 6% BC can be defined as elevated.
6.A 7-year-old boy complains of daytime urinary urgency without daytime incontinence or nocturnal enuresis. Which of the following statements is INCORRECT?
a.Urinalysis should be done to exclude urinary tract infection.
b.Frequency-volume chart is necessary to document whether he has small voided volume throughout the day.
c.Uroflowmetry may disclose a staccato flow pattern suggesting dysfunctional voiding.
d.Postvoid residual urine may be normal or elevated.
e.Anticholinergics will be the first-line treatment for him.
7.Regarding dysfunctional voiding, which statement is INCORRECT?
a.Dysfunctional voiding is characterized by an intermittent and/or fluctuating flow rate due to intermittent contractions of the periurethral striated or levator ani muscles during voiding in neurologically normal children.
b.A uroflow with electromyogram (EMG) or a videourodynamic study is required to document dysfunctional voiding.
c.Staccato, interrupted, plateau, and even normal flow patterns can be observed in children with dysfunctional voiding.
d.Dysfunctional voiding is frequently associated with urinary tract infection (UTI), vesicoureteral reflux, and various types of LUTS.
e.Dysfunctional voiding is frequently observed in children after 1 year.
8.A 13-year-old boy complains of persistent nocturnal enuresis after medical treatment with antidiuretic hormone. Uroflowmetry disclosed voided volume = 250 ml, Qmax = 11.3 ml/s, plateau shaped curve. Postvoid residual urine was 10 ml. Which statement is incorrect?
a.He may have congenital bladder outlet obstruction.
b.If he had delayed bladder neck opening time (more than 4 seconds), he may have primary bladder neck dysfunction.
c.Because he had a plateau-shaped uroflowmetry curve, discoordinated sphincter is unlikely.
d.If image studies such as voiding cystography or videourodynamic study disclosed point stenosis at anterior urethra, an anterior urethral valve can be diagnosed.
e.None of the above.
9.A 3-year-old girl is seen with febrile UTI and left grade 3 vesicoureteral reflux (VUR). She had an uroflowmetry of voided volume = 200 mL, Qmax = 22 mL/sec, and staccato flow pattern. Postvoid residual urine was 22 mL.
a.She may have dysfunctional voiding.
b.The predicted success rate of antireflux surgery is around 95%.
c.Bladder overdistention may be the cause of staccato flow pattern.
d.Fluid restriction and timed voiding may reverse this abnormal voiding pattern.
e.Abnormal voiding posture may be the cause of staccato flow pattern.
Answers
1.c. Increase in bladder capacity and decrease in voiding frequency. Development of normal bladder function involves an increase in bladder capacity in response to an increase in urine production. The voiding frequency decreases, whereas the voided volume of each micturition increases with age.
2.e. Higher Pdetmax is observed in both male and female infants.
Urodynamic studies of infants with normal lower urinary tracts have documented significantly higher Pdetmax in both male and female infants compared with adults, although it was also noted that male infants had significantly higher Pdetmax compared with female infants.
3.b. Micturition is initiated with a full bladder by a simple spinal cord reflex. Studies have shown that even in full-term fetuses and newborns, micturition is modulated by higher centers.
4.e. All of the above. Detrusor overactivity during filling causes frequent attacks of sudden and imperative sensations of urge (urgency) which are often counteracted by voluntary contraction of the pelvic floor muscles in an attempt to compress the urethra (hold maneuver) exhibited as squatting (Vincent's curtsy+ sign). Children with urge syndrome have small bladder capacities for age.
5.b. The International Children's Continence Society (ICCS) views 6 years as the minimum age to adequately report lower urinary tract symptoms, and 5 years as the minimum for functional bowel dysfunction. ICCS defines 5 years of age as the minimum age to adequately report lower urinary tract symptoms (LUTS) and 4 years for functional bowel dysfunction.
6.e. Anticholinergics will be the first-line treatment for him. Based on the measurement of PVR, Thom et al. classified overactive bladder (OAB) as complete or incomplete emptying. Anticholinergics were recommended for OAB with complete emptying, and α-adrenergic antagonists for OAB with incomplete emptying (Thom, 2012).*
7.e. Dysfunctional voiding is frequently observed in children after 1 year.
Dysfunctional voiding is frequently observed in infancy and subsides after 1 year of age.
8.c. Because he had a plateau-shaped uroflowmetry curve, discoordinated sphincter is unlikely. A discoordinated sphincter may occasionally present as a plateau-shaped curve.
9.b. The predicted success rate of antireflux surgery is around 95%.
Operation for VUR associated with LUTD usually results in a lower success rate.
Chapter review
1.In infants and young children, the bladder is an abdominal organ and can readily be palpated when full.
2.Development of normal bladder function involves an increase in bladder capacity in response to an increase in urine production. The voiding frequency decreases, whereas the voided volume of each micturition increases with age.
3.Urodynamic studies of infants with normal lower urinary tracts have documented significantly higher Pdetmax in both male and female infants
compared with adults, although it was also noted that male infants had significantly higher Pdetmax compared with female infants.
4.Immature detrusor sphincter coordination manifested as detrusor hypercontractility and interrupted voiding commonly occurs in the first 2 years of life and results in functional bladder outflow obstruction.
5.Even in newborns, micturition does not occur during sleep, suggesting modulation of micturition by higher centers.
6.The association of constipation with urologic pathology is referred to as the dysfunctional elimination syndrome (bladder bowel dysfunction). Abnormalities of bowel function are commonly present in young children with voiding dysfunction. These children tend to have more psychological difficulties, such as attention problems and oppositional behavior.
7.Giggle incontinence often results in complete emptying of the bladder.
8.In patients who develop acquired bladder sphincter dysfunction, a significant proportion also have bowel dysfunction.
9.There is a significant association of bladder dysfunction with nonresolution of high-grade vesicoureteral reflux.
10.In children, there is a poor correlation between maximal flow rate and outflow resistance. It is better to study the pattern of the flow curve.
11.In any evaluation of voiding dysfunction, abnormalities of the lower spine should be sought.
12.Nocturnal urine output in many enuretic children is in excess of bladder reservoir capacity during sleep.
13.Many enuretic children have a marked reduction in functional bladder capacity when compared with age-matched controls, and may have detrusor instability as well.
14.Normal voiding frequency by age is as follows: age 2 to 4 weeks: once per hour; age 2 to 3 years: 8 to 10 times per day; age 12 years: 4 to 6 times per day.
15.A positive family history may be present in many cases of nonneurologic LUTS in children.
16.All children with LUT dysfunction should have a screening ultrasound study, which should also include an assessment of residual urine.
17.Ultrasound measurement of bladder wall thickness is correlated with LUT dysfunction in children.
18.In general, a PVR greater than 20 mL is abnormal in children.
* Sources referenced can be found in Campbell-Walsh Urology, 11th Edition, on the Expert Consult website.