Evaluation and diagnosis of bladder dysfunction in children

INTRODUCTION — Bladder dysfunction, also referred to as voiding dysfunction, is a general term to describe abnormalities in either the filling and/or emptying of the bladder. It is a common problem in children and constitutes up to 40 percent of pediatric urology clinic visits [1]. In some children, bladder dysfunction is associated with constipation referred to as bowel bladder dysfunction, which had been previously called dysfunctional elimination syndrome (DES).

Daytime urinary incontinence, a common feature of bladder dysfunction, can cause major stress in school-age children [2,3], and negatively impact a child's self-esteem [4]. Thus, it is desirable to identify and treat affected school-age children as early as possible.

The evaluation of non-neurologic bladder dysfunction in children will be reviewed here. The etiology and clinical features of bladder dysfunction in children are discussed separately. The clinical features, evaluation, and management of children with bladder dysfunction due to myelomeningocele also are discussed separately. (See "Etiology and clinical features of bladder dysfunction in children" and "Management of bladder dysfunction in children" and "Myelomeningocele (spina bifida): Urinary tract complications".)

GOALS OF EVALUATION — The goals of the evaluation for suspected bladder dysfunction in children are to:

●Determine whether the child has an abnormality in either filling and/or emptying of the bladder.

●If there is a bladder function abnormality, the evaluation should determine the underlying cause. Specifically, the assessment should distinguish organic (ie, neurogenic or anatomical) from functional causes of bladder dysfunction because management differs depending upon the etiology. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Etiology'.)

The evaluation for most children with bladder dysfunction can be limited to a thorough history, physical examination, and noninvasive testing, such as a urinalysis and urine culture. In selected children, more extensive evaluation includes urologic imaging studies, measurements of urinary flow, and post-void residual determination. In an even more select group of children, formal urodynamic studies may be required to diagnose the underlying problem and determine the most appropriate therapeutic approach.

WHEN TO SUSPECT BLADDER DYSFUNCTION — Bladder dysfunction should be considered in the following settings:

●Daytime urinary incontinence in school-age or previously toilet-trained children.

●Persistent urinary symptoms such as urgency, dribbling, or pain during urination. (See 'History' below.)

●Bladder dysfunction has been associated with conditions such as vesicoureteral reflux, recurrent urinary infections, and chronic constipation or encopresis. (See "Clinical presentation, diagnosis, and course of primary vesicoureteral reflux" and "Functional constipation in infants, children, and adolescents: Clinical features and diagnosis" and "Urinary tract infections in children: Long-term management and prevention", section on 'Identify and treat bowel and bladder dysfunction'.)

INITIAL EVALUATION — The initial evaluation for suspected bladder dysfunction in a child includes a thorough history including voiding diary, focused physical examination, and minimal laboratory testing.

History — A thorough history is important in determining whether bladder dysfunction is present and, if so, may identify the underlying cause. The history should be tailored to the age of the patient and the appropriate stage in his/her development of bladder control. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Normal voiding'.)

The history should seek information about the following:

●Voiding schedule – Voiding schedule includes the frequency of voids and, in toilet-trained children, the frequency of incontinent episodes. If possible, an estimation of the voided volume should also be obtained. Large voids may indicate a large capacity bladder seen in children with underactive bladders or polyuria.

●Symptoms of bladder dysfunction – Bladder dysfunctional symptoms include urgency, pain during urination, holding maneuvers, hesitancy, dribbling, straining, and an intermittent or weak urinary stream. The definitions for these symptoms are discussed separately. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Definitions of symptoms'.)

Validated survey tools include:

•The Dysfunctional Voiding Symptom Survey, a questionnaire consisting of 10 questions that assess daytime incontinence, constipation, urgency, voiding frequency, and dysuria (table 1) [1]. A scoring system based upon a scale of 0 to 3 for each question results in an overall score indicative of the severity of bladder dysfunction.

•Incontinence Symptom Index-Pediatric, an 11-item questionnaire that is divided into two domains impairment and symptom severity [5].

•Dysfunctional Voiding and Incontinence Symptoms Score that assesses daytime symptoms, nighttime symptoms, voiding habits, bowel habits, and quality of life [6].

Although these validated survey tools have been shown to correlate with clinician clinical impression, the mean symptom scores from these questionnaires were higher than the clinician rating for symptom severity [7]. A comparison found that all three questionnaires were equivalent when evaluating response to treatment [8].

The survey tool we use in our institution uses questions from several validated instruments [9].

●Bowel habits – Because constipation is often seen in children with bladder dysfunction, information regarding the child's bowel habits should be obtained. This includes the frequency of bowel movements; the consistency, caliber, and size of stool; presence of pain during defection; and any history of stool withholding behavior, or fecal incontinence and/or soiling [10]. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Bowel and bladder dysfunction' and "Constipation in infants and children: Evaluation", section on 'Evaluation'.)

●Family history – A family history should screen for any kidney or urologic disorders including bladder dysfunction. It is also useful to obtain the age that other family members achieved urinary continence to determine whether there is a familial maturational delay in achieving bladder control.

●Perinatal and neonatal history – Screening for any evidence of any perinatal or neonatal insult should be included. As examples, perinatal anoxia or congenital infection could alter the central and peripheral nervous system normal coordination of bladder function, resulting in bladder dysfunction.

●Diet intake – The amount and type of fluid should be determined. Excessive fluid intake and/or fluid intake during the nighttime may be reflective of polyuria due to a concentrating defect, diabetes mellitus, or, less often, primary polydipsia. (See "Evaluation of patients with polyuria".)

●Previous urinary tract infection – Urinary tract infection (UTI) with and without vesicoureteral reflux (VUR) are often seen in children with bladder dysfunction. The management of VUR is more difficult in children with bladder dysfunction. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Urinary tract infection' and "Etiology and clinical features of bladder dysfunction in children", section on 'Vesicoureteral reflux'.)

●Neurodevelopment delay and psychological disorders – Children who are developmentally delayed may also be delayed in gaining voluntary bladder control. Although most children with bladder dysfunction do not have behavior problems [11], there appears to be an increased risk of bladder dysfunction in children with attention deficit hyperactivity disorder [12,13]. Several studies report an estimated prevalence of 20 to 50 percent of psychological disorders including depression, anxiety, and ADHD in children with urinary or fecal incontinence [14-16]. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Behavioral and neurodevelopmental issues'.)

●Family/parent/caregiver conflict or stress – Functional causes of bladder dysfunction are often believed to originate from behavioral issues arising from toilet training or personal stress. Voluntary holding with postponement of voiding may be reflective of a conflict between the parent/caregiver and child [11]. The level of stress on the parents/caregivers correlates with the severity of the child's bladder-bowel dysfunction as well as his or her psychosocial difficulties [14,17].

●Toilet training history – The history should include whether toilet training was prolonged, delayed, or stressful, and whether there was a period of dryness after toilet training. As noted above, a stressful or prolonged history of toilet training may be indicative of parent/caregiver and child conflict. Anatomic causes of incontinency, such as an ectopic ureter, will typically have no period of complete dryness after toilet training.

Voiding diary — The use of a three-day voiding diary is helpful to obtain an objective record of bowel and urinary voiding patterns. It should include the time and volume of each void, the time of each incontinent episode, fluid intake, the time of each bowel movement, and any episode of fecal soiling (form 1).

Physical examination — The physical examination is focused on detecting neurologic or urologic abnormalities and includes the following:

●Lower back – The back is examined for cutaneous signs of occult spinal dysraphism or sacral agenesis, such as a presacral dimple, hair patch, lipoma, or asymmetric gluteal cleft. (See "Closed spinal dysraphism: Clinical manifestations, diagnosis, and management", section on 'Examination'.)

●Neurologic examination – A focused neurologic examination should include assessing lower extremity strength and deep tendon reflexes, gait, fine-motor coordination, perineal and anal sensation, anal wink (anocutaneous reflex), and rectal tone. Any abnormality of the neurologic examination may be indicative of a neurologic lesion that also affects the function of the bladder, which is coordinated by an integrated neural network involving both the peripheral and central nervous system (figure 1). (See "Detailed neurologic assessment of infants and children", section on 'Neurologic examination'.)

●External urological and perianal examination

•In boys, the examination includes inspection of the meatus to detect any evidence of meatal stenosis [18]. (See "Complications of circumcision", section on 'Meatal stenosis'.)

•In girls, examination of the labia and vaginal introitus is performed to detect any evidence of labial adhesions (picture 1). These findings may be a cause of bladder outlet obstruction. Areas of skin excoriation or redness may be present, which may be a sign of continuous or severe urinary leakage.

•Perianal inspection provides information about the position of the anus, and the presence of gluteal cleft deviation, dermatitis, and perianal feces, fissures, or hemorrhoids [10]. (See "The pediatric physical examination: The perineum", section on 'Anus and rectum'.)

●Abdominal and rectal examination – Constipation is often an associated comorbidity with bladder dysfunction [10]. In a child with constipation, the abdominal examination may detect low to moderate tenderness due to colonic distension secondary to fecal impaction. The digital rectal examination may reveal a distended rectum that is full of stool. In addition, it provides information on perianal sensation and tone, and function of the anal sphincter. (See "Constipation in infants and children: Evaluation".)

●Observation of the urine stream – If possible, direct observation of the urinary stream during voiding should be performed. It allows the clinician to determine whether there is any evidence of hesitancy, dribbling, intermittency of voiding, or weak stream, which are all signs of bladder dysfunction (movie 1).

●Evidence of sexual or physical abuse – The physical examination should look for signs of physical or sexual abuse because bladder dysfunction can be a presenting sign for child abuse [19]. (See "Evaluation of sexual abuse in children and adolescents", section on 'Physical examination'.)

Laboratory studies — Initial laboratory testing generally does not provide additional useful diagnostic information and should be limited to a urinalysis and urine culture.

Findings on a urinalysis, preferably performed on a first morning void (ie, after a period of fluid restriction), may be suggestive of conditions that present with polyuria such as diabetes insipidus. These include a low specific gravity due to a renal concentrating defect or glycosuria due to diabetes mellitus. (See "Urinalysis in the diagnosis of kidney disease", section on 'Glucose' and "Urinalysis in the diagnosis of kidney disease", section on 'Specific gravity'.)

A urine culture should be obtained if the urinalysis is positive for urine leukocyte esterase and nitrite because children with bladder dysfunction have an increased risk of UTI. Children with UTI will often have a positive urinalysis for pyuria. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Urinary tract infection' and "Evaluation of microscopic hematuria in children".)

Serum laboratory studies (eg, creatinine) are typically not part of the initial evaluation because abnormalities in overall kidney function are rare in children with a normal urinalysis. If there is an abnormal urinalysis suggesting kidney injury or disease (eg, urinary concentrating defect, proteinuria), a serum creatinine is obtained to estimate the glomerular filtration rate and check serum electrolytes. (See "Evaluation of proteinuria in children", section on 'Approach to the child with proteinuria'.)

DIAGNOSIS — The diagnosis of bladder dysfunction is based upon the presence of one or more of the following lower urinary tract symptoms, which are defined elsewhere. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Definitions of symptoms'.)

●Increased frequency

●Urgency

●Hesitancy

●Dribbling

●Use of holding maneuvers to suppress voiding

●Abnormality of urinary flow including weak or intermittent urinary stream

●Abdominal straining during voiding

EVALUATION OF UNDERLYING ETIOLOGY — In children with bladder dysfunction, the underlying cause is often suggested by a constellation of signs and symptoms detected during the initial evaluation.

●Neurologic causes – Neurologic lesions are suggested by any abnormality detected on neurologic examination, cutaneous signs of occult spinal dysraphism or sacral agenesis, or a history of perinatal/neonatal injury. These children require further neurologic evaluation. (See "Myelomeningocele (spina bifida): Urinary tract complications".)

●Anatomical causes – Anatomical causes of bladder dysfunction may be suggested by symptoms of a weak stream, such as in boys with posterior urethral valves, or abnormalities detected by physical examination. Further assessment with imaging of the urological system is required to diagnosis an anatomical etiology.

●Functional causes – Idiopathic bladder dysfunction with no known neurologic or anatomic cause is suggested by findings from the initial evaluation, and a clinical diagnosis is made based upon the presenting symptoms and signs. In most cases, behavioral therapeutic interventions aimed at retraining the bladder and urinary sphincter can be initiated based upon a clinical diagnosis of one of the following forms of bladder dysfunction. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Daytime urinary incontinence'.)

•Overactive bladder – The hallmark symptom of an overactive bladder is urgency.

•Voiding postponement – Children who voluntarily postpone voiding usually have a low voiding frequency rate with large volume voids. These children typically utilize holding maneuvers to suppress voiding.

•Underactive bladder – Some children with voiding postponement will develop underactive bladder with poor or absent bladder contraction. These children will demonstrate straining (eg, Valsalva maneuver) to aid in voiding, and have a weak and interrupted urinary stream. (See 'Shape of urine flow curve' below.)

•Non-neurogenic dysfunctional voiding – Children with non-neurogenic dysfunctional voiding are unable to relax the urethral sphincter and/or pelvic floor musculature during voiding. These children often have constipation consistent with a diagnosis of bowel-bladder dysfunction, which was previously referred to as the dysfunctional elimination syndrome.

DIFFERENTIAL DIAGNOSIS — The differential diagnosis for bladder dysfunction includes:

●Urinary tract infection, which is diagnosed by a positive urine culture. (See 'Laboratory studies' above.)

●Secondary bladder overactivity from constipation, which is diagnosed by history. (See 'History' above.)

●Polyuria – The initial evaluation differentiates patients with polyuria from those with bladder dysfunction by the large volumes of urine that are produced by the former. In many cases, polyuria is a caused by a urinary concentrating defect, which is reflected by a low specific gravity. The exception is polydipsia, which can be identified by a history of excess fluid intake. (See "Evaluation of patients with polyuria".)

REFERRAL AND FURTHER EVALUATION — Further diagnostic evaluation for bladder dysfunction includes:

●Urologic imaging

●Urinary flow measurements

●Urodynamic studies

These studies are generally performed under the direction of a urologist with expertise in evaluating children with bladder dysfunction.

Indications — Indications for further evaluation include the following:

●Failure to improve after several months of an initial trial of conservative management such as timed voiding and treatment of constipation.

●Suspicion of a neurologic or anatomic etiology.

●Children with suspected bladder dysfunction who are not responsive to behavioral modification therapy. Further evaluation can confirm or change the clinical diagnosis prior to the initiation of pharmacologic therapy.

●Constant continuous incontinence, since these children are more likely to have an organic cause such as an ectopic ureter.

●Urinary tract infection or vesicoureteral reflux.

●Suspected kidney damage as indicated by proteinuria or an elevated serum creatinine.

Imaging

Ultrasonography — A kidney and bladder ultrasound is the most commonly used imaging modality in the assessment of children with bladder dysfunction. An ultrasound is a noninvasive study that should be performed in any child with a suspected neurologic or anatomical lesion, urinary tract infections, or symptoms suggestive of an obstructive process (eg, weak urinary stream).

Ultrasonography can provide the following information:

●Detection of anatomical abnormalities, such as hydronephrosis due to obstruction or vesicoureteral reflux, a double collecting system with an ectopic ureter, or kidney scarring.

●Detection and measurement of post-void residual volume. A volume greater than 20 mL upon repeat measurement indicates incomplete bladder emptying [20-22]. Incomplete emptying is seen in a number of bladder dysfunction disorders including underactive bladder and dysfunctional voiding.

●Measurement of bladder wall thickness – The bladder wall is normally less than 3 mm thick when full or less than 5 mm thick when relatively empty [23]. A thickened bladder wall is suggestive of outlet obstruction due to an anatomical (eg, posterior urethral valves) or functional abnormality (eg, non-neurogenic dysfunctional voiding). However, the most common cause of a thickened bladder wall is an overactive bladder (92 percent of cases in one series) [24].

Voiding cystourethrogram — A voiding cystourethrogram (VCUG) is a contrast study that involves urethral catheterization and evaluates the bladder during both the filling and voiding phases [25,26]. A VCUG is used primarily to assess for vesicoureteral reflux, but also provides information on bladder shape and capacity, bladder emptying, and the presence of posterior urethral valves. The voiding images may also demonstrate evidence of a non-relaxing sphincter. The scout film, a plain film of the abdomen, provides information on bony abnormalities and constipation [27].

A VCUG is not typically used to evaluate bladder dysfunction. However, it is obtained in children with urinary tract infection, or in boys suspected of having posterior urethral valves (ie, thick-walled bladder and a weak urinary stream). (See "Clinical presentation, diagnosis, and course of primary vesicoureteral reflux", section on 'Diagnosis'.)

Magnetic resonance imaging — Any child with evidence of neurologic dysfunction should be evaluated with a lumbosacral magnetic resonance imaging (MRI) to look for occult neurologic lesions.

However, a normal physical examination does not completely exclude occult spinal cord disorders. In one study of 81 children with bladder dysfunction that was refractory to medical intervention and a normal physical examination, 39 percent had pathologic findings on MRI [28]. Another study suggested expanding the criteria for spinal cord imaging to include children with impaired bladder sensation or incomplete bladder emptying, because these findings occur more frequently in children with spinal cord abnormalities [29].

Based upon these data, we obtain a lumbosacral MRI in patients suspected of having a neurologic abnormality, or in those who remain refractory to treatment and/or demonstrate urodynamic findings consistent with a neurologic defect. (See 'Urodynamic testing' below and "Myelomeningocele (spina bifida): Urinary tract complications".)

Urinary flow measurement — Measurement of urinary flow (uroflowmetry) is typically only available in a urologic practice caring for patients with bladder dysfunction. It provides useful information regarding the pattern of urine flow that is often diagnostic of an underlying cause, making it unnecessary to pursue more invasive urodynamic testing. Uroflowmetry provides information regarding the emptying phase of the bladder, but not the filling phase.

For uroflowmetry testing, children are asked to wait until they feel at least a strong desire to void, and if possible, to wait until they have an urgency to void. A minimum flow volume of 100 mL is required to assess urine flow. The child then voids into a collection device that produces a urinary flow curve, which provides the following information:

●Shape of urine flow

●Voided volume

●Flow time

●Maximum flow rate (Qmax)

●Average flow rate

During voiding, electromyographic activity of the urethral sphincter and pelvic floor musculature can be assessed using pads affixed to the perineum. Sphincter activity should be absent during voiding. The presence of sphincter activity during voiding is indicative of dysfunctional voiding.

However, there is poor correlation between urinary flow measurements and clinical response to therapy [30-32]. In one retrospective study, biofeedback appeared to improve continence and decrease the frequency of urinary tract infection [31]. Clinical responses to biofeedback did not correlate with changes in urinary flow measurements [33]. Similar poor correlations were reported between urinary flow patterns and the clinical response to anticholinergic treatment [30] or the use of timed voiding [32].

The lack of correlation between uroflowmetry and clinical response likely reflects the fact that the majority of cases with incontinence are due to a failure of the storage function of the bladder and not the emptying function, which is measured by uroflowmetry.

Shape of urine flow curve — The International Children's Continence Society (ICCS), a global multidisciplinary organization of clinicians involved in the care of children with lower urinary tract dysfunction, developed categories for normal and abnormal urine flow patterns that correlate with the underlying causes of daytime urinary incontinence (figure 2) [20,22]. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Daytime urinary incontinence'.)

●The normal urine flow curve is smooth and has a parabolic shape.

●The tower flow curve has a high amplitude and short duration peak. It may be produced by the explosive voiding contraction of an overactive bladder. However, children with an overactive bladder may have a normal-appearing parabolic curve because an overactive bladder is primarily an abnormality of the filling phase.

●A plateau curve with low amplitude may be seen when bladder obstruction is present from urethral stricture or posterior urethral valves or the urethral sphincter and/or pelvic floor musculature are contracted during voiding (ie, dysfunctional voiding).

●A staccato curve with fluctuating urine flow of high and low amplitude can be seen in children with dysfunctional voiding.

●An interrupted curve is a fractionated urinary flow of low amplitude and long duration seen in children with underactive bladder who have either an absent or weak detrusor (bladder) contraction. The peaks of urinary flow correlate with the use of abdominal straining (ie, Valsalva maneuver) to empty the bladder.

Other parameters — Uroflowmetry provides quantitative information on voided volume, maximum flow rate (Qmax), and average flow rate. The minimum acceptable urine flow rates are 10 mL/sec in boys and 15 mL/sec in girls [34].

Total bladder capacity is calculated as the sum of the voided volume and the post-void residual (determined by ultrasonography). The calculated bladder capacity is compared with the expected bladder capacity (EBC), which is discussed separately. (See "Etiology and clinical features of bladder dysfunction in children", section on 'Bladder capacity'.)

Bladder capacity may be diminished in children with overactive bladders. In one study, for example, children with an overactive bladder had a bladder capacity that was 57 percent of the EBC for age [35]. In contrast, children with underactive bladder have increased bladder capacity.

Urodynamic testing — Fluoro-urodynamic testing is a specialized invasive study that involves placement of urethral and rectal catheters to study the bladder during filling and voiding in an awake child. Information obtained includes evaluation of detrusor instability, incontinence, compliance, bladder pressure, bladder capacity, urine flow rate, sphincter activity, and bladder emptying. The bladder is filled with contrast during a urodynamic test, allowing radiographic visualization.

Urodynamic testing detects abnormalities during both the filling and voiding phase and is thought to be useful in separating the more common disorder of overactive bladder (filling phase abnormality) from those of dysfunctional voiding due to abnormal sphincter or pelvic musculature contraction during voiding. (See 'Urodynamic patterns' below.)

In a retrospective study of 89 children with bladder dysfunction without a neurologic lesion who had failed conservative therapy, 63 percent had an abnormal urodynamic study, which was twice as likely to be due to a filling rather than a voiding abnormality [36].

However, a prospective multicenter study reported a poor correlation between symptoms and urodynamic testing in children with incontinence [37]. In this study, during urodynamic testing, 60 of 91 children with urgency did not have evidence of an overactive bladder during bladder filling, and 47 of 100 children with a history consistent with non-neurogenic dysfunctional voiding did not have increased pelvic floor activity during voiding. In addition, there was poor correlation between the response to treatment and urodynamic findings. Although editorial comments raised concerns about this study, including the reliability of the clinical diagnoses and technical consistency of the urodynamic testing, these findings highlight the lack of accurate methods to identify the cause of all bladder dysfunction symptoms.

Nevertheless, urodynamic testing is a currently available modality that identifies functional voiding abnormalities in most children with daytime incontinence who fail conservative therapy. It is rarely required because most cases of bladder dysfunction are due to functional causes in which behavioral therapy is successful in bladder function retraining and improvement of symptoms [38]. In those patients, it may identify a bladder functional abnormality to direct individualized therapy.

Indications — Urodynamic testing is generally reserved for the following conditions:

●A known or suspected neurologic lesion.

●Severe bladder dysfunction with evidence of kidney damage or hydronephrosis.

●High imperforate anus.

●Selected cases of abnormal urinary tract anatomy, such as posterior urethral valves.

●Children with suspected functional bladder dysfunction that is refractory to treatment in whom the diagnosis still remains uncertain after urologic imaging and urinary flow measurement.

Urodynamic patterns — Although standard values are available for urodynamic studies in children [39], care must be taken in interpreting the results, especially in infants in whom reported transient urodynamic dysfunction has improved over time [40].

Voiding disorders and their urodynamic findings include the following (table 2) (see "Etiology and clinical features of bladder dysfunction in children"):

●Overactive bladder — Children with an overactive bladder have involuntary detrusor contractions during the filling phase, referred to as detrusor overactivity, with increased bladder pressure of more than 15 cm H2O. There are no other voiding abnormalities; these children have normal sphincter activity during both the filling and voiding phases, and normal detrusor contractions during voiding. In case series of children with voiding dysfunction symptoms, detrusor overactivity detected by urodynamic testing is present in 52 to 58 percent of patients compared with only 5 to 18 percent of asymptomatic children [39,41-43].

●Dysfunctional voiding – This disorder occurs in children with a neurologic lesion, referred to as detrusor sphincter dyssynergy, or in neurologic intact patients, referred to as non-neurogenic dysfunctional voiding. In both groups of children, there is abnormal contraction of the urethral sphincter during voiding. These children have normal detrusor function during both the filling and voiding phases, and normal sphincter contraction during the filling phase. However, there is a subgroup of children with dysfunctional voiding that also have an overactive bladder [44].

●Underactive bladder – Children with an underactive bladder have a large capacity bladder and incomplete emptying of the bladder during voiding because of inadequate detrusor contraction. These children have normal sphincter function during both the filling and voiding phases.

RESOURCES — The International Children's Continence Society provides guidelines for the evaluation and treatment of bladder dysfunction, as well as information for the general public.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Urinary incontinence in children".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Daytime wetting in children (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Importance of early detection – Bladder dysfunction, defined as an abnormality in either filling and/or emptying the bladder, is a common problem in children. Daytime urinary incontinence, in particular, can be a source of major stress in school-age children. Thus, it is desirable to identify and treat affected children as early as possible. (See 'Goals of evaluation' above and 'When to suspect bladder dysfunction' above.)

●Initial evaluation – The initial evaluation consists of a thorough history that may include keeping a voiding diary (form 1), focused physical examination, and laboratory testing (eg, urinalysis, urine culture, and, in some children, serum creatinine). (See 'Initial evaluation' above.)

●Diagnosis – The clinical diagnosis of bladder dysfunction is based upon the presence of one or more voiding symptoms that include urgency, hesitancy, dribbling, use of holding maneuvers to suppress voiding, abnormality of urinary flow including weak or intermittent urinary stream, and the use of abdominal straining during voiding. (See 'Diagnosis' above.)

●Evaluation of underlying etiology – The underlying cause of bladder dysfunction is often suggested by a constellation of signs and symptoms detected during the initial evaluation. It is important to distinguish uncommon organic (ie, neurologic and anatomic) causes of bladder dysfunction from the more common functional etiologies (eg, overactive or underactive bladder). In children with functional disorders, behavioral interventions aimed at retraining the bladder can be initiated based upon a clinical diagnosis. (See 'Evaluation of underlying etiology' above.)

●Differential diagnosis – The differential diagnosis includes urinary tract infection, secondary bladder dysfunction due to constipation, and polyuria. (See 'Differential diagnosis' above.)

●Referral and advanced testing – Further evaluation includes imaging of the urinary tract, measurement of urinary flow, and urodynamic testing. These studies are performed by urologists and generally reserved for patients suspected of having a neurologic or anatomic etiology, patients who are not responsive to behavioral modification therapy, or those who have constant continuous incontinence, urinary tract infection, vesicoureteral reflux, or suspected kidney damage. (See 'Referral and further evaluation' above.)