Diagnosis and Management of Urinary Incontinence in Childhood

Committee 9 Diagnosis and Management of Urinary Incontinence in Childhood Chairman S. TEKGUL (Turkey) Members R. JM NIJMAN (The Netherlands), P. H OEBEKE (Belgium), D. CANNING (USA), W.BOWER (Hong-Kong), A. VON GONTARD (Germany) 701 CONTENTS E. NEUROGENIC DETRUSOR A. INTRODUCTION SPHINCTER DYSFUNCTION B. EVALUATION IN CHILDREN F. SURGICAL MANAGEMENT WHO WET C. NOCTURNAL ENURESIS G. PSYCHOLOGICAL ASPECTS OF URINARY INCONTINENCE AND ENURESIS IN CHILDREN D. DAY AND NIGHTTIME INCONTINENCE 702 Diagnosis and Management of Urinary Incontinence in Childhood S. TEKGUL, R. JM NIJMAN, P. HOEBEKE, D. CANNING, W.BOWER, A. VON GONTARD In newborns the bladder has been traditionally described as “uninhibited”, and it has been assumed A. INTRODUCTION that micturition occurs automatically by a simple spinal cord reflex, with little or no mediation by the higher neural centres. However, studies have indicated that In this chapter the diagnostic and treatment modalities even in full-term foetuses and newborns, micturition of urinary incontinence in childhood will be discussed. is modulated by higher centres and the previous notion In order to understand the pathophysiology of the that voiding is spontaneous and mediated by a simple most frequently encountered problems in children the spinal reflex is an oversimplification [3]. Foetal normal development of bladder and sphincter control micturition seems to be a behavioural state-dependent will be discussed. event: intrauterine micturition is not randomly distributed between sleep and arousal, but occurs The underlying pathophysiology will be outlined and almost exclusively while the foetus is awake [3]. the specific investigations for children will be discussed. For general information on epidemiology and During the last trimester the intra-uterine urine urodynamic investigations the respective chapters production is much higher than in the postnatal period are to be consulted. (30ml/hr) and the voiding frequency is approximately 30 times every 24 hours [4]. I. NORMAL DEVELOPMENT OF Immediately after birth voiding is very infrequent during BLADDER AND SPHINCTER the first few days of life. The first void may only take CONTROL place after 12 to 24 hours. After the first week frequency increases rapidly and peaks at the age of 2 to 4 weeks to an average of once per hour. It then Normal bladder storage and voiding involve low- decreases and remains stable after 6 months to about pressure and adequate bladder volume filling followed 10 to 15 times per day. After the first year it decreases by a continuous detrusor contraction that results in to 8 to 10 times per day, while voided volumes increase bladder emptying, associated with adequate relaxation by three to fourfold. of the sphincter complex. This process requires normal sensation and normal bladder outlet resistance. The During the postnatal period, micturition control neurophysiological mechanisms involved in normal mechanisms undergo further changes and extensive bladder storage and evacuation include a complex modulation. Using ambulatory bladder monitoring integration of sympathetic, parasympathetic and techniques in conjunction with polysomnographic somatic innervations which is ultimately controlled by recordings it has been shown that even in newborns a complex interaction between spinal cord, brain stem, the bladder is normally quiescent and micturition does midbrain and higher cortical structures [1]. not occur during sleep [5]. Achievement of urinary control is equally complex This inhibition (or lack of facilitation) of detrusor and as yet not fully understood: various developmental contractions during sleep is also observed in infants stages have been observed [2]. with neurogenic bladder dysfunction who have marked 703 detrusor overactivity while they are awake. In response addition to at least three other events occurring to bladder distension during sleep, an infant nearly concomitantly: always exhibits clear electro-encephalographic • a progressive increase in functional storage evidence of cortical arousal, facial grimaces or limb capacity, movements, or actual awakening. Sleeping infants are always seen to wake up before the bladder • maturation of function and control over the external contracts and voiding occurs. This arousal period may urinary sphincter, be transient and the infant may cry and move for a brief period before micturition and then shortly afterward • and most importantly achievement of volitional go back to sleep. Because this wakening response is control over the bladder-sphincteric unit so that already well established in newborns, it follows that the child can voluntarily initiate or inhibit a micturition the control of micturition probably involves more reflex [11]. complicated neural pathways and higher centres than The final steps are usually achieved at the age of 3 has been appreciated. There is also strong evidence to 4 years when most children have developed the that a pronounced reorganisation of pre-existing adult pattern of urinary control and are dry both day synaptic connections and neural pathways involved and night. The child has learned to inhibit a micturition in bladder control occurs during the early postnatal reflex and postpone voiding and voluntarily initiate period. micturition at socially acceptable and convenient times In newborns micturition occurs at frequent intervals and places. This development is also dependent on and may have an intermittent pattern although bladder behavioural learning and can be influenced by toilet emptying efficiency is usually good. In over 80 percent training, which in turn depends on cognitive perception of voids the bladder empties completely [6]. of the maturing urinary tract. During infancy voiding pressures are much higher It is understandable that this series of complex events than in adults. It has also been noted that these is highly susceptible to the development of various pressures are higher in boys than in girls (mean pdet types of dysfunction. Various functional derangements max of 118 vs. 75 cm H2O, respectively) [7,8]. of the bladder-sphincter-perineal complex may occur during this sophisticated course of early development These higher detrusor pressures decrease of normal micturition control mechanisms. These progressively with increasing age. In up to 70 percent acquired “functional” disorders overlap with other of infants (up to the age of 3 years) with normal lower types of bladder functional disturbances that may urinary tracts, intermittent patterns of voiding were have a more organic underlying pathophysiological observed. They tend to disappear with increasing basis. age, and are thought to represent variations between individual infants in the maturation of detrusor and sphincteric co-ordination during the first 1 to 2 years II. NORMAL VALUES of life. Videourodynamic studies have confirmed these findings [5,7,8,9,10]. 1. NORMAL BLADDER CAPACITY Between the age of 1 and 2, conscious sensation of bladder filling develops. The ability to void or inhibit The bladder capacity increases during the first 8 years voiding voluntarily at any degree of bladder filling of life roughly with 30 ml per year, so with an average commonly develops in the second and third years of capacity of 30 ml in the neonatal period, a child’s life. Central inhibition is crucial to obtain continence. bladder volume can be calculated as Y = 30 + 30 X, where Y = capacity in ml and X = age in years (Figure During the second and third year of life, there is 1) [12]. progressive development towards a socially conscious continence and a more voluntary type of micturition Hjälmås described a linear correlation that could be control develops. The child becomes more aware of used up to 12 years of age: in boys, Y = 24.8 X + 31.6, the sensation of bladder distension and the need to in girls Y = 22.6 X + 37.4, where Y is capacity in ml, urinate, as well as social norms and embarrassment and X is age in years [13]. associated with urinary incontinence. Through an It should be noted that these data were obtained active learning process, the child acquires the ability during cystometric investigations. Cystometric capacity to voluntarily inhibit and delay voiding until a socially is generally less than normal bladder volumes. convenient time, then actively initiate urination even Obviously, the relation between age and bladder when the bladder is not completely full, and allows capacity is not linear for all ages, nor is the relation urination to proceed to completion. During the first between body weight and bladder capacity [14]. years of life, gradual development to an adult type of voluntary micturition control that conforms to the social Another formula to calculate bladder capacity in infants norms depends on an intact nervous system, in is: bladder capacity (ml) = 38 + (2.5 x age (mo)) [10]. 704 None of these formulas have been acquired from a population based study and do not reflect normal bladder capacity. Normal bladder capacity should be regarded as the maximum voided volume of urine and shows huge variation. Girls were found to have a larger capacity than boys, but the rate of increase with age was not significantly different between them. Data on ‘normal’ bladder capacity have been obtained in continent children undergoing cystography, with retrograde filling of the bladder. Data obtained from the International Reflux Study indicate that there is not a linear relation between age and capacity and that there is a huge variability (Figure 3) . 2. NORMAL VOIDING The micturition frequency of the foetus during the last trimester is approximately 30 per 24 hours. It decreases to 12 during the first year of life, and after Figure 1 : Bladder capacity using the formula that it is gradually reduced to an average of 5±1 Y= 30 + 30 X (Y= capacity in ml, X = age in years) voidings per day [10, 15]. The normal range for the micturition frequency at age Kaefer and co-workers demonstrated that a non-linear seven is 3 to 7 [16]. model was the most accurate for the relation between By age 12, the daily pattern of voiding includes 4-6 age and bladder capacity, and they determined two voids per day [17].

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