Voiding Dysfunction in Children

1. Voiding Dysfunction in Children By Dr.TurkyK. Al-Mouhissen Urology Chief Resident - WR King Abdulaziz Medical Center - WR

2. Normal Bladder Function in Infants & Children: • The bladder is an abdominal organ • Detrusor consists of meshwork of smooth m. which has the ability to elicit maximal active tension over a wide range of length • This allows the bladder to be filled at low pressure (compliance) • Reservoir function determined by activity of detrusor m. and bladder outlet • Bladder sphincter plays a major role in urinary continence by closure of bladder neck & proximal urethra

3. Literature suggests that • Immature detrusor-sphincter coordination, manifested as detrusor hypercontractility and interrupted voiding, commonly occurs in 1st1-2 years causing a degree of functional bladder outflow obstruction (Sillen et al,1992;Yeung et al,1998) • Some found significant age related differences in the histologic structure of the sphincter compared to adults • Activation, coordination, and integration of various parts of the bladder-sphincter complex involves central, somatic & autonomic nervous system through • Sacral parasympathatic (pelvic n.) • Thoracolumbar symp. (hypogastric & sympathatic chain) • Sacral somatic n. (pudendal n.)

4. Parasymp. N. fibers run in pelvic n. (S2-S4) to supply the pelvic and vesical plexuses before entering the bladder • Symp. n. arises from (T10-L2) to inferior mesenteric ganglion hypogastric n. to the pelvic plexus & bladder • There is also symp. innervation from T10-L2 supplying the detrusor and urethral sphincter • The somatic nervous system (pudendal n.) supplies the periurethral pelvic floor muscles • The sensory & motor n. carried by all 3 nerves innervate the bladder and urethral sphincter

6. Symp. supply causes • Detrusor relaxation (B receptors) • Smooth m contraction at trigone & bladder neck (alpha receptors) • Parasymp. supply causes detrusor contraction (muscarinic receptors) • Pudendal supply causes striated sphincter contraction • Within the spinal cord, information from bladder afferents integrated with other sources and projected to brain stem centers to coordinate with mic. centers

7. Development of Normal Bladder Function and Micturition Control • CMG studies on normal infants showed • bladder function in young children is very different from adults • During the 1st 2-3 years of life • There is progressive development from initially indiscriminate infants voiding pattern to more socially conscious and voluntary (adult) type of micturition

8. The natural evolution of bladder control entails nervous system & depends on: • Progressive increase in bladder functional storage capacity • Maturation of voluntary control over the urethral striated muscle sphincter • Development of direct volitional control over the bladder sphincter unit, so that the child can voluntary initiate or inhibit micturition reflex

9. Change in bladder function parameters • Voiding frequency • During the 3rd trimester, the fetus voids at rate 30 times/24 hrs • Immediately after birth, this drops for the 1st days only • Increases again after 1st 1/52 to reach a peak by 2-4 /52 to an average once/hour • This rate declines to 10-15 times/day at 6-12 mo. • 8-10 times/day by 2-3 years

10. This reduction in voiding frequency observed during the 1st years of life related mainly to an increase in bladder capacity parallel to body growth • By the age of 12, voiding pattern is very similar to that in adult ( 4-6 voids / day )

11. Bladder capacity • An adequate reservoir function of urine storage is necessary to meet the increase rate of urine production and decreased voiding frequency in the growing child Bladder capacity can be estimated For young infants: Bladder capacity (ml) = 38 + 2.5 * age (mo) For children: Bladder capacity (ml) = (age [yr] + 2) * 30 koff’s formula Bladder capacity (ml) = 30 + (age [yr] * 30 Hijalma’s formula

12. In parallel to increase in bladder capacity, the mean voided volume of each micturation increases with age • CMG studies showed that most infants with incomplete maturation of det.- sphin. coordination before the age 1, are still able to have satisfactory emptying (>80) • There are limited studies on detr. pressure at voiding in infants due techn. difficulties

13. Limited data documented higher maximum detr. pressure with mict. than in adults • Male infants voided significantly higher pressure than females (mean Pdetmax 118 vs. 75cm H20, P<.03) • Studies showed that high detrusor pressures noted during micturition were mainly observed only during the 1st year of life & decreased progressively with age

14. Evolution of Normal Micturition Control • Traditionally, it has been assumed that micturition occurs by simple spinal reflex with no mediation by higher neural centers • Recent studies showed that even in full term fetuses and newborns, mict. Is modulated by higher centers • Further extensive modulation occurs during the postnatal period

15. During the 2nd & 3rd year of life, there is a progressive development toward a socially conscious continence and a more voluntary (adult) type mict. • The final steps usually achieved at 3-4 yrs • Most develop the adult pattern of urinary control & will be dry day & night • The child has learned to inhibit a mict. Reflex and postpone voiding and voluntarily initiate mict. At socially acceptable time & place

16. Neurologic control of normal mic. occurs at different levels of CNS from the spinal cord (sacral mic. centers) to the brain stem (pontine mic. Centers) • Cerebellum, basal ganglion, limbic system, thalamus and hypothalamus, and cerebral cortex • bladder is unique among other visceral organs • its function is under control of somatic and autonomic n. system • Beside acetylcholine & NE, other neurotransmitters involved during bladder stimulation • PG substance P, Opioid, vasoactive intestinal peptide, neuropeptide Y

17. Transitory Detrusor-Sphincter Discoordination in Infancy • Studies showed that all children may transiently display some degree of abnormal bladder-sphincter function • Urodynamic findings show association of high voiding pressures and interruption of flow BUT noimpairment of overall bladder empting • This type of dysfunction resolved with a period of successful toilet training, transient or intermittent, and does not persist

18. Non-Neuropathic Bladder Sphincter Dysfunction in Children

19. Reported 15 % of 6-year old children suffer from Non-Neuogenic B.S.Dysfunction • Dysfunctional voiding may • starts with detrusor instability with sphincter & pelvic floor overactivity • then develops gradually fractionated voiding with increasing PVR • Finally, develops bladder decompensation and the lazy bladder syndrome • Distinction between Neuropathic & Non-neuropathic bladder dysfunctions may not be clear

20. The term non-neuropathic is based purely on the fact that no obvious and identifiable neurologic lesions can be identified • In adults, lower urinary tract function has been well understood and standardization of terminology has been established • In contrast, neural control over the bladder-sphincter unit in children is age dependent and is much more variable and complex

21. Etiologic Classification of Bladder Dysfunction • Derangement of Nervous Control: • Congenital malformation of CNS, e.g.: • myelomeningocele, spina bifida, caudal regression synd., tethered cord • Developmental disturbances, e.g.,: • Mental retardation, dysfunctional voiding, urge synd. • Acquired conditions, e.g.: • CP, progressive degenerative diseases of CNS, transverse myelitis, MS, vascular malformations, trauma of spinal cord

22. Disorders of Detrusor & Sphincteric Muscle function: • Congenital conditions • Muscular dystophy, neuronal dyplasia • Acquired conditions • Chronic bladder distension, fibrosis of detrusor & bladder wall • Structural abnormalities • Congenital conditions • Bladder extrophy, epispadias, cloacal anomoly, uretroceles, PUV, prune belly syndrome • Acquired conditions • Traumatic stricture, damage to sphincter or urethra • Other unclassified conditions • Giggle incontinence • Hinman syndrome • Ochoa syndrome (urofacial syndrome)

23. Functional classification of bladder dysfunction based on functional state of the bladder-sphincter complex with respect of detrusor activity bladder sensation bladder compliance and function urethral function during the filling & voiding phase of CMG

24. During the filling phase: • Detrusor activity • Normal or stable • Overactive : phasic involuntary detrusor contractions which occur spontaneously or provoked by alteration of posture, coughing, walking, jumping • Unstable: contraction unrelated to underlying neurologic disorder • Detrusor hyperreflexia : overactivity related disturbance of neural control mechanism

25. Bladder sensation during filling phase: • Normal / hypersensitive / hyposensitive / absent • Bladder capacity • normal/ / high / low • Compliance • Normal / high / low • Urethral function • Normal / incompetent

26. During the voiding phase • Detrusor activity • Normal: Voiding achieved by voluntarily initiated detrusor contractions that is sustained and cannot usually suppressed voluntarily until after 4 year old • Underactive • Acontractile • Urethral function • Normal • obstructive

27. Bladder-Sphincter dysfunction during filling • Overactive (unstable) bladder, urge syndrome, urge incontinence • Traditionally the infant bladder has been described as unstable or uninhibited • Recent studies showed that bladder is normally quiescent and stable even in newborn • Clinically, the condition of (unstable bladder) is best exhibited by URGE SYNDROME with or without urge incontinence

28. Urge syndrome characterized frequent attacks of sudden and imperative sensations of urge due to detrusor overactivity during filling (girls>boys) • The unstable contractions are often counteracted by voluntary contractions in the pelvic floor muscles to externally compress the urethra (hold maneuvers) exhibited as squatting in many cases • Urge incontinence consists of small quantities of urine loss • More in afternoon when the child plays and is not alert enough to contract the pelvic floor in response to the urge sensation

29. Functional urinary incontinence • Defined as involuntary loss of urine due to failure of control of bladder sphincter unit, frequent enough to cause social or hygienic problem with the absence of underlying anatomic causes • Stress incontinence represents involuntary leakage of urine occurring when the intravesical pressure exceeds the bladder outlet or urethral pressure in the absence of measurable detrusor contractions • Unlike adults, true stress incont. Extremlely uncommon in neurologically normal children and generally not associated with abnormal CMG

30. Giggle incontinence: • Involuntary and typically unpredictable wetting during giggling or laughter • In contrast to stress incontinence, it produces much larger volume of urine leak amounting to complete bladder emptying • CMG may be normal or occasionally demonstrate some detrusor overactivity • Rx is difficult bt sometimes a course of anticholinergic drugs may help • Some suggested that it’s centrally mediated and hereditary disorder that may respond to CNS stimulants as methylphenidate

31. Bladder-Sphincter dysfunction during bladder emptying • Dysfunctional voiding • Characterized by incomplete relaxation or overactivity of the pelvic floor muscles during voiding • Can manifest in different patterns depending on the degree of outflow obstruction caused and the status of the detrusor activity

32. Staccato and fractionated voiding • In staccato voiding the urinary stream is often delayed after the onset of detrusor contraction and is typically interrupted resulting in a few small squirts of urine passed in quick sensation • Interrupted voiding caused by periodic bursts of pelvic floor muscle activities during micturition resulting in characteristic abrupt elevation of voiding pressure coinciding with paradoxical cessation of urinary flow • Flow time usually prolonged and bladder emptying incomplete

33. Fractionated voiding is characterized by infrequent & incomplete emptying secondary to detrusor inactivity • Micturition occurs in several small discontinuous fractions due to poor detrusor contractions • Significant PVR • Abdominal straining usually evident to improve emptying • Straining paradoxically counteracted by reflex increase in pelvic floor muscles that is triggered by increase in intravesical pressure

34. Infrequent voiding and (lazy bladder) syndrome • Described together as they represent a spectrum of diseases that are more commonly occurs in girls • The lazy bladder syndrome is generally regarded as the endpoint of long standing dysfunctional voiding occurring in a fully decompensated system • Due to chronic functional outflow obst., there is gradual deterioration in detrusor contractility and emptying efficiency • PVR & bladder capacity increase progressively with inefficient emptying

35. Bcs urge sensation is either absent or diminished, voiding is very infrequent and occasionally the child may not void for 8-10 hrs or longer if engaged in activity • Typical presentation, the mother always complains that the child never voids unless told to do so • Other presentations • Recurrent UTI, Overflow incontinence, constipation • CMG findings • Large bladder capacity, very high compliance on filling, absent detrusor contractions, voiding associated with increased abdominal pressures

36. Hinman’s Syndrome & Occult Neuropathic bladder • Different names: • Nonneurogenic neurogenic bladder / subclinical neurogenic bladder / Hinman syndrome / occult neuropathic bladder • Acquired form of bladder-sphincteric dysfunction in children • characterized by a combination of bladder decompensation with incontinence, poor emptying, and recurrent UTI • Most children have significant bowel dysfunction • Has all the clinical & CMG features of neuropathic dysfunction but NO neuologic pathology • CMG shows marked sphincteric overactivity with abrupt contractions of pelvic floor

37. Ochoa (urofacial) syndrome: • Children have all classic features of dysfunctional voiding, including urinary incontinence, recurrent UTI, constipation, reflux, Upper tract damage + peculiar painful or apparently crying facial expression during smiling • Autosomal recessive, located on chromosome 10 • CMG shows sustained contraction of external sphincter during voiding

38. Of 66 children reported by Ochoa: • 33% renal functional impairment • 26% HTN • 24% ESRD • Bcs neural ganglion controlling the facial muscles are situated very close to the pontine micturition centers • A small genetically predetermined congenital neurologic lesion in this area may be responsible for both the peculiar facial expression & bladder dysfunction

39. Postvoid dibbling • Involuntary leakage of urine immediately after voiding • Refers to post toilet trained girls who dribble soon after standing up after a void and otherwise normal with no other urinary symptoms • May be result of vesicovaginal reflux where urine is trapped in the vagina during voiding & once the child stands, the urine dribble out • When in doubt, can be confirmed by MCUG • Harmless, tends to resolve with age • Child may be taught to empty her vagina by simply voiding with her thigh apart & leaning forward after voiding before getting up

40. Dysfunctional Elimination Syndrome, Constipation, & Bladder Dysfunction • DES refers to broad spectrum of functional disturbances that may affect the urinary tract including that of functional bowel disturbances • The close proximity of the rectum to posterior bladder wall make it possible that • gross distension of the rectum by impacted feces can result in mechanical compression of the bladder & bladder neck leading to urinary obstruction

41. Classified as : • Functional disorder of filling • Overactive, overdisteded, insensate bladder, may be associated with fecal impaction or rectal distension with infrequent call to stool • Functional disorder of emptying • Over recruitment of pelvic floor activity during voiding causing interrupted / incomplete emptying, with defecation difficulties due to nonrelaxation of puborectalis or pain on defecation

42. DES influenced the clinical outcome of ureteric reimplantation surgery for VUR • Children with constipation had the highest likehood of developing breakthrough UTI & requires surgery • DES had an adverse effect on the rate of spontaneous reflux resolution requiring an average 1.6 years longer to outgrow reflux than in children without DES • After successful Rx of constipation • 89% of those with daytime incontinence and 63% of nighttime incontinence became dry Loening-Baucke et al (1997) • Management of the underlying dysfunction should be given priority in the treatment protocol of children with conditions such as VUR / incontinence / UTI bsc successful Rx may significantly improve outcome

43. Relationship Betw. Bladder Sphincter Dysfunction, VUR, & Recurrent UTI • Impairment in the function of lower tract often coexists with recurrent UTI & VUR without neurologic pathology • The most common abnormalities of lower tract coexist with VUR are • Detrusor overactivity • Uncoordinated detrusor sphincter during voiding • Reflux may be worsened by detrusor instability

44. Studies showed that infants with UTI & VUR have high prevalence of high voiding detrusor pressure • Male refluxers have higher maximum detrusor pressure > female • May be due to high urethral resistance of the longer male urethra and smaller urethral meatus with anatomic difference in the external urethral sphincter • Spontaneous resolution of VUR may be delayed in presence of abnormal dynamics of the bladder • Successful Rx of underlying bladder dysfunction result in marked increase in the rate of spontaneous resolution of reflux & recurrent UTI

45. Evaluation of Non-Neurogenic Bladder Sphincter Dysfunction • History • Majority present after toilet training with symptoms of nighttime / daytime urinary incontinence or both • May present earlier with UTI or VUR • Hx should include questions to exclude neurologic & congenital abnormalities • Bowel dysfunction can coexist in the form of encorpresis, constipation and fecal impaction • Urinary Hx should include symptoms of storage & voiding of urine

47. Physical examination: • Usually normal • Careful examination is required • Occasionally, palpable bladder may be found • External genitalia examination • Abnormalities of lower spine • Neural tubal defect • Asymmetrical gluteal folds • Hairy patch • Dermovascular malformation • Lipomatous abnormality of sacral region • Rectal exam. may reveal impacted stool

48. Laboratory • Not routinely required • Urine analysis may be performed to R/O bacteruria & glucosuria • Serum & urine osmolarity may be looked in case of nocturnal enuresis

49. Ultrasound • 1st line investigation • Simple, reliable, available, & noninvasive tool • Provides anatomical & functional problems • Recently used to measure bladder parameters used in calculating bladder volume & wall thickness index (BVWI) • BVWI classified into normal / thick / thin • Studies showed these classifications corresponded closely to CMG findings of bladder dysfunctions • This classification can act as reliable tool to guide for further invasive investigations

50. Other imaging studies: • Radiologic examination of the spine may be necessary to exclude neuologic causes • MCUG may be needed to R/O VUR & to assess the status of the urethra • Urodynamics studies: • To describe the physiologic parameters involved in bladder mechanics during filling & voiding