A Review of Bowel and Bladder Control Development in Children: How Gastrointestinal and Urologic Conditions Relate to Problems in Toilet Training

Urologic and gastrointestinal problems in children are of great concern to parents. In most cases, such problems represent no organic disease or serious behavior disorder but nevertheless can cause more serious complications in toilet training than parents recognize. Although bowel and bladder symptoms in otherwise healthy children typically are transient, untreated issues can spiral into physical, behavioral, and developmental problems that disrupt toilet training and maintenance of bowel and/or bladder continence. Chronic wetting and soiling may persist well into the school years and often are refractory to empirical medical treatment.Clinical experience, however, suggests that in most children these problems can be managed successfully within the realm of general pediatric practice. Two important tools for evaluation are available to the pediatrician: good normative data on bowel and bladder function in children, and management algorithms for toilet training that emphasize pathophysiologic patterns within the context of normal development. Interventions emphasize early anticipation, breaking predictable behavioral and dietary cycles that can turn acute problems into chronic problems. This is especially important during the toilet training years.Almost all children have wetting and/or soiling accidents at one time or another. As with other models of developmental milestones, transient regressions or delays in toilet training logically can be expected. Bowel maturation typically precedes bladder maturation, which is not surprising, given the respective complexities of the developmental processes.1 An estimated 15% to 20% of children will become partially toilet trained but continue to have wetting accidents after age 5.2,3 Additionally, at least 20% of developmentally normal children 18 to 30 months of age may refuse stool toilet training at some point.4Children with encopresis (chronic fecal soiling at age 4 and older) typically soil during the day and are unaware of and unable to control their soiling accidents.5 Soiling may be attributable to leakage of liquid feces and mucus surrounding a large fecal mass or to incomplete defecation, when anal sphincter constriction propels some of a partially extruded fecal mass into the clothing and some of it back into the rectosigmoid.6 The most severe problems occur when habitual stool withholding leads to paradoxical anal spasm and so-called “functional” megacolon, characterized by a flaccid, overdistended sigmoid colon and rectal insensitivity.6 In these cases, children cannot feel when bowel movements occur and hence are at high risk for overflow incontinence.7 It is now generally accepted that most children with primary or secondary encopresis (ie, occurring before or after toilet training) do not have serious psychological or behavioral disorders and therefore may be managed in the general pediatric setting.8“Toilet refusal” has additional behavioral nuances in that typically it occurs in children at approximately 3 years of age who have regular bowel movements in their clothing or diapers but refuse to defecate in the toilet.9 Toilet refusal and encopresis are generally interchangeable from a clinical standpoint because they share a constellation of symptoms: constipation, low-fiber intake, painful bowel movements, bowel-movement withholding, and/or toilet avoidance. However, knowledge still is uncertain regarding what predisposes children to toilet refusal, whether there is an increased risk for megacolon or overflow incontinence in these children, and indeed even where they fit on the continuum of normal to abnormal bowel function.10Enuresis, repeated (at least twice monthly) involuntary voiding during the day or night in otherwise normal children 5 to 6 years of age (or once monthly for older children), is by far the most common type of voiding problem presenting to the office-based pediatrician.2 Most voiding problems arise between toilet training age and puberty (average age, 4.5 years).3 Boys are twice as likely as girls to have nocturnal enuresis.11It is estimated that at least 20% of children with normal bladders have day and night wetting, and in the vast majority, these problems are self-limiting.2,12 Nonetheless, if wetting problems remain unresolved or untreated beyond toilet training age, social incontinence can become debilitating from a psychosocial standpoint—an estimated 5% of 10-year-olds and 2% of 12- to 14-year-olds are estimated to have nocturnal enuresis.11,13Children with “uncomplicated” enuresis do not have an increased incidence of urologic disease and show normal physical, psychiatric, and neurologic findings, as well as normal urinalysis and urine culture.2,3,13 It has been widely, although not universally, accepted that in these children, the normal nocturnal bladder volume simply exceeds the daytime bladder capacity caused by some normal delay in development, such as a delay in the growth of functional bladder capacity.2 Other explanations may be that the child simply cannot awaken in time to urinate, possibly because of sleep-arousal disorders and/or nighttime antidiuretic hormone deficiency.2 Some of these children also may have a family history of enuresis, slightly delayed developmental milestones, or certain sex-specific behavior problems.2,11In cases of isolated bed-wetting, there generally appears to be a strong learned element, with discernible reinforcements or environmental stressors that disrupt toilet training.14Like encopresis, wetting during toilet training can evolve into failure to attain social continence, and early voiding problems can lead to difficulties with peers, as well as parental disapproval, irrational rewards and/or punishments, and possibly physical abuse.13,15The current descriptive standard for functional bladder abnormalities in the absence of demonstrable neuropathy is the “unstable” bladder, sometimes also called persistence of the “infant” bladder, “uninhibited” bladder, or unstable detrusor muscle of the bladder. These terms all basically connote uninhibited bladder contractions in a child who should have achieved voluntary bladder control. Because all infants have spontaneous bladder contractions and because bladder maturation is a gradual process differing from child to child, an unstable bladder is not by definition abnormal.16In the most severe situations, an absence of functional synergy arises between the detrusor and sphincter in the child with uninhibited bladder contractions who habitually constricts the sphincter to stay dry. Children with this syndrome, the “Hinman bladder,” cannot relax the sphincter in the face of detrusor contractions (unlike children with simple unstable bladders, who have normal reflex relaxation of the external sphincter once their bladder starts emptying). The result is a potential buildup of very high intravesicular pressures that can cause structural damage to the bladder and dilatation of the upper urinary tract that, in very severe cases, can cause renal damage.16 These anatomic changes tend to persist long after bladder instability and incontinence resolve.2Children with “complicated” enuresis make up a small but important clinical cohort who require evaluation for functional, anatomic, and/or neurologic abnormalities.2 Generally, complicated voiding symptoms are distinguishable by their sudden onset and/or progressive course. In these children, enuresis can be associated with daytime frequency; dribbling; urgency and urge incontinence; polyuria; infrequent voiding; blood in the urine; a weak or intermittent urinary stream; straining to void; or a history of chronic constipation, encopresis, and/or urinary tract infection (UTI).2,3,11,16Encopresis and enuresis represent complex arrays of signs and symptoms that have multiple gastrointestinal and genitourinary components, as well as behavioral/environmental elements, including toilet training issues.17 In treating these conditions, pediatricians need to work closely with parents and patients to identify and address common patterns and predisposing factors that transform transient bowel and bladder symptoms into chronic problems.5Idiopathic diarrhea and constipation are quite common among healthy children. As children approach toilet training age, their stools tend to become more susceptible to abnormal dryness and hardness, or alternatively, to having a longer transit time.18–20 Chronic constipation accounts for 3% to 5% of pediatric primary care outpatient visits.21Fortunately, in most cases these problems are transient and self-limiting. In a population sample of healthy children, for example, the proportion of parents registering chronic digestive complaints and constipation in their children decreased from 27% and 16%, respectively, when the children were 22 months old to 5% and 3%, respectively, by the time their children were 40 months old.18Despite its usually benign course, however, in the minority of children who are susceptible, constipation poses a real risk of becoming a chronic gastrointestinal disturbance that can have a long-range effect on toilet behavior. Studies have firmly established that young children with severe chronic constipation habitually withhold stools in an attempt to keep hard fecal matter out of contact with sensitive portions of the bowel wall and/or to reduce pain from anal fissures.6 During withholding, contraction of the external anal sphincter and nearby muscles ejects the feces back into the rectosigmoid, where the fecal mass dries, hardens, and enlarges.6 The resulting fecal impaction predisposes to additional withholding. Hence, withholding sets up a vicious cycle of fecal impaction, pain, and more withholding; in some children, this cycle can have a prolonged impact on toilet use. If untreated, transient changes in bowel function associated with constipation can lead to bowel-control problems.5 Fecal soiling and impaction account for approximately one fourth of visits to pediatric gastroenterologists.6 Unfortunately, constipation often is occult and can be overshadowed by the primary gastrointestinal or urologic complaint (eg, toilet refusal, daytime wetting, recurrent UTI). Moreover, the symptoms of constipation and its precipitating factors (eg, stool withholding, low-fiber diet) often are not obvious. The central role of constipation in toilet training problems, therefore, cannot be overemphasized to the primary care physician or to parents.For a variety of reasons, the toilet training process itself can be a primary cause of stool-withholding behavior and constipation. Children using regular toilets rather than a potty chair simply may not have sufficient leverage (because they cannot push against the floor) to eliminate stools.17 Additionally, the toddler in training may begin to withhold stools as a response to excessive parental pressure to maintain bowel control. Children who initially resist stool toilet training are most likely to become chronic soilers if they habitually withhold stools (thereby promoting fecal impaction and primary encopresis), complete toilet training late (past 42 months of age) and/or have siblings in diapers, or if their parents do not impose limits on soiling behavior.4 The importance of initial bowel continence is highlighted by the fact that children with secondary encopresis, particularly those who are managed early (within 12 months), appear to have much less trouble gaining permanent control over their bowel function compared with their peers who were never toilet trained successfully.22 Within the early elementary grades, approximately 1.5% of children are still encopretic, with boys outnumbering girls by five to one.11,23It is highly significant that a majority of youngsters who do not attain social bowel continence have a history of constipation beginning at toilet training age—indeed, descriptions of early withholding as remembered by parents of older encopretics match the descriptions given by parents of encopretic toddlers.6 Typically, an early period of painful defecation sets off a pattern of progressively infrequent defecation that stretches over years, until by school age the child has very infrequent, very large bowel movements and regular (sometimes daily) soiling.6 By this age, failure to maintain social bowel continence is associated with intense parental disapproval, feelings of embarrassment or shame, and difficulty in social situations.5Persistence of an “immature” diet appears to be a cause of transient constipation in susceptible toddlers.18Specifically, fiber deficiency has been implicated, because fiber clearly lags behind the increase in other food categories during the preschool years.18 It has been reported, for example, that between 2 and 4 years of age, calorie and in proportion to growth but a fiber at approximately is that most children to a low-fiber diet over but a minority may significant constipation in response to chronic fiber important dietary presenting to the general is an gastrointestinal complaint called chronic diarrhea which has been the bowel or colon of This is by far the most cause of prolonged diarrhea in otherwise healthy is characterized by recurrent of diarrhea longer than 3 and typically occurs in children 6 months to 3 years of and are and all cases by the time a child age 4 or is toilet Because not failure to or pediatricians have managed these children with dietary such as and and and encopresis were once to be symptoms in children with urinary incontinence but are now to with bladder complicated enuresis is often characterized as of a complex including encopresis, and The of this for the general are simple for constipation and may urologic evaluation and in the majority of As however, often constipation in children with bladder even after urologic parents may constipation but it as an and never it to clinical between unstable bladder, and recurrent also cannot be of children with recurrent have an unstable bladder, and approximately also have possibly of children with and an unstable bladder have no history of In all these bladder instability is the common for urologic in otherwise healthy for this is that increased intravesicular pressure leads to recurrent attributable to blood within the bladder or to increased contact of the bladder with with structural in the genitourinary These in turn to This is by that is common in children with enuresis or secondary nocturnal enuresis, symptoms that are associated highly with bladder and also that of against enuresis in some to of the feces and constipation, can be a predisposing for although the for this is In patients with voiding incomplete of the bladder, in with the constipation, be a cause of the urinary Some patients with voiding have which in In such pressure in the bladder can cause secondary which in with urinary has the potential to damage the An of this is called the approach to encopresis and enuresis medical and behavioral data and the impact of toilet training and on bowel and bladder This approach the physician to predictable patterns of symptoms and to signs and symptoms that additional The of this approach is the medical including physical urine and rectal and if The is the clinical including the medical developmental and dietary toilet and parental to The is behavioral (eg, a voiding nocturnal enuresis a physical urinalysis and urine and wetting, urgency weak urine or urinary for bladder neuropathy and/or an unstable bladder. In the may children with occult unstable bladder who for evaluation of recurrent or but not for wetting most children with do not have voiding although approximately of children with such problems show signs of of some of intravesicular bladder instability can is not surprising, because clinical can be very or possibly as a result of in external urinary sphincter The of children who with and urge incontinence have very bladder contractions and normal sphincter the have and to maintain continence at the of high intravesicular pressures that cannot be until detrusor contractions or The unstable bladder in turn evaluation for problems, including signs of constipation and physical of these children may an bladder, normal anal sphincter and fecal the most important of the medical therefore, is to out bladder instability in children who with recurrent In the of the child with wetting, a physical and neurologic urine and renal and bladder be generally is not a in these cases, but it is for parents that there is no organic cause of bladder multiple of the and the bladder and after to out bladder wall and increased urine and and are if but be if the physical and neurologic evaluation to the of for complicated enuresis also can be associated with abnormal renal bladder or bladder, and of the urinary tract such as an bladder or a and for these patients renal and bladder of the external urinary and voiding should the to for renal and/or bladder the external where or urine leakage may be and the where may be anal sphincter and also should be in the It is important to that the absence of not out neuropathy other signs sudden onset of voiding large urine capacity bladder problems and/or straining to urinate, and a history for and/or neurologic clinical for the of enuresis and The during the are to identify pathophysiologic patterns within the of symptoms and to an of the primary (eg, toilet training) within which the problems parents and the can a of to the of bowel and bladder also should the age at which toilet training and of toilet should be or (eg, as well as pressures to toilet that may have to patterns after months or more of continence. Some children have behavioral problems sufficient to cause enuresis or In these cases, it is important to or or a in or Although the of significant problems be with to a pediatric or other factors may not require a they can with bowel and bladder continence. or stool-withholding may represent a delayed response to excessive parental pressure on the child to complete toilet training before the child is or to that and/or as example, daytime occurs in children as a transient response to a in which the child small the of also address whether the child bladder continence and whether symptoms are or and/or are The physician and parents should that intermittent wetting or soiling can be caused simply by a delay in clothing off or after using the The age at which the problem also is important in the for example, older children are more likely to have occult bladder instability or significant damage from intravesicular as well as significant behavioral problems. of recurrent urinary infection or constipation also are physician also should the child during the of if physical can be particularly when of abnormal example, infrequent bladder are typically school girls who with recurrent often with intermittent enuresis, with parents that the child until the to The (ie, of the voiding problem is often the physician it and that the child has the child may at least an after to and may to often not at all during straining during is often in these children, because the often detrusor contractions and a bladder. Additionally, although bladder instability is generally by a pattern of wetting, an of bladder instability is in girls in which the the and the to urinary by the parents is an important to the history with the bowel and bladder function and behavioral factors that may to the with parents is to on to the urine and bowel and all the of (eg, and The by also is for the and of a as well as for but important nuances in such as in the and/or of accidents as to the of for children with enuresis and encopresis are toilet training and social continence. the importance of early to parents that are and over the long urologic (eg, and dietary are empirical and of and as with may even the example, the the most for treating in children, has a may be to that there is no organic disease when the problem has beyond toilet training or has initial Unfortunately, gastrointestinal and urologic often are more and to the child than the symptoms are for children with bladder, or upper urinary tract or severe anal or signs of megacolon, or those who have to on vast majority of children do not have functional, anatomic, or disorders and do not require or the should be to to complaints and transient maintain over intermittent and to out organic increase and their of symptoms and their The role of constipation should be particularly to on symptoms (eg, hard bowel movements, of blood in the also need to be that enuresis and encopresis generally on their children do not have control over and rewards or cannot that the child will not or soil and may the it is important for the physician and parents to that psychosocial issues associated with encopresis and enuresis during toilet training from issues in older children who are unable to attain social to treating enuresis and encopresis in the primary care constipation dietary and if and breaking cycles that can transform symptoms into chronic wetting and soiling problems, and the unstable bladder. to toilet training is central to these example, parents need behavioral to with young children in prolonged gastrointestinal problems have become to toilet refusal (ie, the child pain and with Some of these children will but not or defecate the potty chair or that they do not when they are to or have a bowel may out toilet training but become and refuse even to approach the The therefore be to work with parents on to to the to eliminate into the potty chair or An important for parents to the cycle is to children to defecate as as they feel the urge and to as much time on the potty chair or toilet as they is to the child soiling also may need to psychological to parents and patients with to the gastrointestinal symptoms for example, as with bowel syndrome, chronic symptoms in children are by physical or has been with that and the child to bowel control. the of to parental and have been with a and of toilet behavior. a and of toilet However, using and in as well as real by time and to out such may significant to their by parents and other including dietary fiber and may most preschool children never become on for dietary changes in with chronic gastrointestinal complaints are not However, it has been that small dietary to the be for susceptible children, who be to or other Some in chronic diarrhea has been with dietary from or all to the proportion of from the of the behind the is it simply may be that and have on gastrointestinal and therefore respectively, up and gastrointestinal transit to chronic constipation and/or diarrhea be to the developmental in terms of and a of this parents that healthy children in the of and that are and may have strong for an important in which can parents to dietary successfully is to emphasize that it is to to maintain a at the it should be that spontaneous bladder contractions will in a normal child, can be a highly for detrusor and the volume at which contractions the functional capacity of the It has been that a of to with can to control spontaneous bladder reduce the of and the of possibly for in some in is to be an important to such but and parents often are to do this because for acute emphasize excessive Moreover, if constipation and fecal impaction also are problems, and be because of fecal impaction will to the In these of constipation with dietary and has been to encopresis, and voiding office-based that chronic gastrointestinal and urologic complaints typically represent no serious organic disease or behavioral problems but can cause significant complications in toilet and encopresis often are behavioral of benign gastrointestinal and urologic symptoms that, if untreated, can vicious cycles of incontinence and increased to more serious physical and behavioral problems. The treating children with chronic gastrointestinal and urologic complaints to and work closely with parents to toilet problems, identify patterns and predisposing and out the children who may have organic disease and/or problems. such as dietary and when by behavioral often are the to these cycles early and to in toilet training and continence.