Urodynamic Abnormalities in Neurologically Normal Children with Micturition Dysfunction

0022-5347 /84/1316-0074$02.00/00

THE

Vol. 132, July

JOURNAL OF UROLOGY

Copyright © 1984 by The Williams & Wilkins Co.

Printed in U.S.A.

Urological Neurology and Urodynamics URODYNAMIC ABNORMALITIES IN NEUROLOGICALLY NORMAL CHILDREN WITH MICTURITION DYSFUNCTION GEORGE D. WEBSTER,* R. BRUCE KOEFOOT, JR.

AND

STEPHEN SIHELNIK

From the Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina

ABSTRACT

We evaluated by video urodynamic study 60 children between 4 and 16 years old who had presented with various combinations of urinary frequency, diurnal incontinence, enuresis, voiding symptoms, recurrent urinary infections and upper tract changes. A number of seemingly distinct categories of detrusor dysfunction could be identified, which may have a bearing on logical treatment selection. In addition, abnormalities of sphincter activity were noted in 12 children. The limitations and interpretation difficulties of urodynamic studies in children are stressed. Micturition problems are encountered frequently in children and usually manifest with persistent enuresis, urinary frequency, urgency, diurnal incontinence and recurrent urinary tract infections in the absence of any obvious underlying cause. Historically, conventional urological evaluation of these patients using excretory urography (IVP), voiding cystourethrography and endoscopy has been unsatisfactory. More recently, urodynamic studies have been introduced, offering an assessment of function rather than anatomic appearance, which tends to be more revealing. 1- 3 These studies vary in sophistication from simple cystometry to multifunction studies monitoring bladder and rectal pressure, sphincter electromyography and urine flow rate during bladder filling, storage and voiding. The addition of intermittent simultaneous fluoroscopic screening of the bladder and outflow tract in video urodynamics provides a further dimension to these studies, enhancing their interpretability, particularly with respect to identifying incoordinate proximal or distal sphincter activity. 4 The difficulties of interpretation of urodynamic studies and, particularly, of sphincter electromyography are accepted widely, and this is even more true in pediatric practice. The identification of bladder instability by cystometry is based on an assumption that the child is trying to inhibit voiding while the bladder is being filled, which cannot always be guaranteed. A number of reported series of children with micturition dysfunction have stressed the identification of external sphincter dyssynergia. 3 • 5- 7 However, its identification rests on a belief that the electromyographic activity recorded truly is involuntary and not artifact due to either the recording method, discomfort experienced by the child making him incompletely relax or inappropriately contract the sphincter, or simply artifact produced by the child straining to void. 8 We present a series of 60 children with various lower urinary tract symptoms who underwent elaborate urodynamic studies.

symptoms and recurrent urinary infections. There were 23 boys and 37 girls between 4 and 16 years old (mean age 8.76 years). All children were neurologically normal and exhibited no physical signs nor radiographic evidence of occult spinal dysraphism. Children with a history of urethral valves were excluded from the study. In all cases an IVP, voiding cystourethrography and endoscopy were done but no cause for the symptoms was identified. The multifunction urodynamic study was performed on a Picker tilting x-ray table. The child was unsedated and total bladder pressure, rectal pressure, their subtraction product detrusor pressure and striated sphincter electromyography were monitored on a 4 or 6-channel Life-Tech instrument during bladder filling and storage. During voiding, which initially was done with the patient in the erect position to facilitate fluoroscopic screening, urine flow rate also was monitored. Periods of x-ray exposure were brief and intermittent to avoid excessive gonadal irradiation, and the total x-ray dose was calculated to be less than that of a standard IVP. Urodynamic aspects of the study were repeated until consistent results were achieved. Girls were allowed to void on a commode. An SF feeding tube for filling cystometry and a 4F polyethylene tube for monitoring intravesical pressure changes were inserted in the urethra. During the voiding study the feeding tube was removed and the child voided around the 4F pressure measurement catheter. Before this series suprapubic access had been used but extravesical extravasation occurred on 2 occasions, considerably prolonging hospital stay, which led to its abandonment for all but exceptional circumstances. The cystometry filling rate was 35 ml. per minute using room temperature 14 per cent diatrizoate meglumine solution. Filling was continued until maximum capacity was achieved. The sphincter electromyogram was recorded using needleintroduced hooked wire electrodes inserted into the external anal sphincter. Although some controversy exists as to whether anal sphincter activity mimics that in the periurethral sphincter, it is our belief that in the nonneurogenic child in whom we are primarily looking for pelvic floor activity it is appropriate. We have been able to insert the wire electrodes without anesthesia and with only momentary discomfort. After a delay to allow insertional activity resultant from electrode injury to resolve, activity was monitored on a chart strip recorder and an oscilloscope with audio monitor.

MATERIALS AND METHODS

The study included 60 children with various combinations of urinary frequency, enuresis, diurnal incontinence, voiding Accepted for publication February 7, 1984. Read at annual meeting of Southeastern Section, American Urological Association, New Orleans, Louisiana, March 28-April 1, 1982. * Requests for reprints: Box 3146, Duke University Hospital, Durham, North Carolina 27710. 74

URODYNAMIC ABNORMAUT~ES IN CHILDREN WITH MICTURITION DYSFUNCTION URO!YINAMIC FEATURES It~ 60 CHILDREN WITH

7 ~···...

MICTURITION DYSFUNCTION

~ Poor compliance bladder

I

1 i (18%)

e••·~~=,···

5 (8%)

L_3(5%) _______

L--Large capacity bladder

Small capacity bladder

11 (18%) had external sphincter dysfunction

voiding problems with symptoms of hesitancy, intermittency, straining to void or residual urine in 12. There were 5 relatively distinct groups of patients identified on filling cystometry (fig. 1). The largest group included 28 patients (47 per cent) with unstable bladders who had phasic uninhibited contractions stronger than 15 cm. water pressure (fig. 2). There were 13 patients (22 per cent) who had a poor compliance type of bladder with a steep tonus limb on the cystometrogram, indicating poor bladder distensibility. Three patients (5 per cent) had small capacity bladders with normal stability and compliance but with increased sensitivity to stretch, 5 (8 per cent) had a large capacity bladder and 11 (18 per cent) were normal. Incomplete external sphincter relaxation during voiding was identified by sphincter electromyography and fluoroscopy in 11

1 had bladder neck dysfunction

50

FIG. 1 FLOW RATE

50

Normal flow

cc/sec

lnlerrupted

!low

chimic'leristics

FLOW RATE cc /sec

Hyperactive

sphincter oclivity

SPHINCTER E.M.G.

Ccrnrdinafed 100

External Sphincter E.M.G.

TOTAL BLADDER PRESSURE cm H20

50 0

100

100

TOTAL

BLADDER 50

DETRUSOR PRESSURE cm H20

PRESSURE

50

0

0

JOO

100 RECTAL PRESSURE

DETRUSOR PRESSURE 50 cm H20

50

cm (J

0

FIG. 3. Multichannel urodynamic study of child with recurrent urinary infections, diurnal incontinence and enuresis during filling and voiding. During supine bladder filling unstable contractions to 32 cm. water occur. During voiding interrupted slow flow rate is achieved and incomplete striated sphincter relaxation is evident. High spikes of detrusor pressure coincide with sphincter closure and represent isometric contraction of detrusor.

100

RECTAL PRESSURE 50 cm H20

Incidence of symptoms, infections and reflux according to urodynamic findings

0 FIG. 2. Multichannel filling and voiding study shows pediatric unstable bladder. Micturition study is interpreted as normal. Pressure spike superimposed on commencement of micturition study is isometric contraction resulting from apprehensive child voluntarily interrupting urine flow. Second spike is aftercontraction that also is isometric event. RESULTS

The presenting symptoms of the 60 children varied and included diurnal, nocturnal or both types of incontinence in 51, enuresis alone in 2, history of urinary infections in 34 and

Bladder Type

No. Pts.

Incontinence

Infections

Unstable Poor compliance Small capacity Large capacity Norm! cystometrogram Totals

28

27

16

13 3 5 11

13 3 3 5

8 l 4

4

60

5

2

51

34

12

20

11

7

6

4

7

External sphincter dysfunction

Voiding Problems 4 1

3

Reflux 10

4 1 3

76

WEBSTER, KOEFOOT AND SIHELNIK

cases (18 per cent) (fig. 3). Of these patients 9 (82 per cent) had an unstable or poorly compliant bladder. Neither a history of incontinence or voiding problems nor recurrent infections accurately predicted the likelihood of occurrence of incomplete sphincter relaxation. Bladder neck dysfunction was diagnosed in 1 child, who had a moderately obstructive urodynamic voiding study but a coordinated striated sphincter and fluoroscopic evidence of poor funneling of the bladder neck during micturition. Vesicoureteral reflux had been documented previously or was seen on the video study in 20 cases. Its distribution according to the type of bladder in which it occurred is shown in the table. Of then patients who had sphincter dysfunction 7 (64 per cent) exhibited vesicoureteral reflux. · DISCUSSION

It has been shown previously that children with enuresis alone without diurnal symptoms have a low incidence of urodynamic abnormalities. 9 We rarely perform urodynamic studies on such children, which may account for our high yield of positive urodynamic findings (83 per cent). It has been reported previously that the urodynamic findings dictate the most appropriate therapy, and review of our cases supports this contention. 10 Patients with unstable bladders appear to respond best to anticholinergic medications and are customarily treated with oxybutynin chloride suspension. Generally, we start at a dosage of 2.5 mg. 3 times daily, incrementally increasing the dose until therapeutic success is achieved, side effects prevent further use of the drug or the maximum allowable dose range for the medication is reached. Those patients with a poor compliance (hypertonic) bladder are by urodynamic definition also unstable because the intravesical terminal filling pressure is >15 cm. water. However, they may be a distinct group because factors other than muscle hypertonicity can impair bladder distensibility. In these patients anticholinergics and spasmolytics also were used and there is some evidence that imipramine therapy and a-blocking agents also may be of benefit. 10•11 The high incidence of infections in the unstable bladder group (59 per cent) is in close agreement with others. 7 •12 During uninhibited bladder contractions the child voluntarily contracts the external sphincter in an attempt to maintain continence, which increases intravesical pressure causing mucosal ischemia that may be a prime influence in the development of recurrent infections. "Milk-back" of potentially infected urine also may predispose to infections. When the detrusor contracts uninhibitedly the bladder neck opens and urine fills the urethra down to the level of the distal sphincter where voluntary contraction maintains continence. If the uninhibited detrusor contraction abates, this urine is "milked back" into the bladder. In the female patient this portion of the urethra is potentially contaminated so that bacteria may be carried back into the bladder. The group with large capacity bladders has been reported previously by us and we believe that these cases are due to a learned phenomenon of infrequent voiding with resultant overdistension and myogenic damage. 13 Therapy is aimed at improving bladder emptying and may include cholinergic agents, such as bethanechol chloride, a-adrenergic blocking agents, such as phenoxybenzamine to decrease outlet resistance, a timed voiding drill and perhaps intermittent catheterization in intractable cases. This group also had a higher incidence of recurrent infections (80 per cent), which should improve with more efficient emptying. In the 11 patients (18 per cent) who had normal urodynamic studies no logical therapy could be advised and it was recommended that the diurnal wetting be treated using a bladder drill program involving timed voiding and an attempt to educate the child to recognize and heed bladder cues. The enuresis was managed in the customary empiric fashion using imipramine or a bed alarm and recurrent infections were prevented by '

prophylactic antibacterials. Similarly, in the 3 patients who had small capacity bladders that were normal in all other respects urodynamic studies suggested no logical therapy and simple hypersensitivity to stretch is the probable cause. External sphincter hyperactivity is a most difficult entity to identify and because of procedure-induced artifact it is exceedingly difficult to diagnose accurately using sphincter electromyography recorded on a chart strip alone. The main source of artifact includes the contraction of other muscle groups, particularly if the patient is straining to void. Involuntary contraction of the sphincter also may occur because of the discomfort and uncertainty that the child experiences due to the instrumentation and the laboratory surroundings. Repetitive studies may lessen but not totally exclude such artifact, and the use of an oscilloscope with audio monitor further helps to identify true external sphincter activity. The simultaneous fluoroscopic study is invaluable to examine the electromyography findings, since if there is electromyography activity but the membranous urethra appears wide open fluoroscopically then that activity must arise elsewhere than the sphincter. Since these were all neurologically normal children this in appropriate sphincter activity was called hyperactivity rather than dyssynergia. It may be a learned phenomenon, originally developing during a urinary infection when painful voiding resulted in its occurrence following which it became habitual. Alternatively, the child may have learned to contract the sphincter voluntarily to prevent incontinence during uninhibited bladder contractions, a habit that is then carried through to the voiding act and results in an interrupted flow. In an attempt to correct it all irritative factors, .such as urinary infection or bladder instability, should be resolved. Other methods advocated for intractable cases include the use of diazepam, behavioral therapy, biofeedback and urethral dilation. Diazepam is probably the simplest method available, since biofeedback requires considerable physician input and special equipment. Urethral dilation is not recommended, particularly in the male patient in whom urethral trauma may result. The reflux may be due to abnormal bladder dynamics caused by uninhibited bladder contractions and inappropriate sphincter activity, resulting in abnormal pressure characteristics within the bladder and also in architectural alterations of the musculature. Treatment must be directed initially at correction of the micturition dysfunction by the aforementioned methods and subsequently at correction of reflux, should it persist and be of a surgical grade. No single clinical symptom accurately predicted the type of urodynamic abnormality found. However, it is true that the patient with a large capacity bladder was incontinent and infected more frequently, and suffered voiding dysfunction or reflux. Although reflux was more common in those patients with sphincter dysfunction during voiding incontinence, infections and voiding problems were pot (see table). CONCLUSIONS

We were surprised by the high incidence of urodynamic abnormalities occurring in these neurologically normal children. Abnormalities of detrusor function, identified by cystometry and micturition study, occurred in 82 per cent and sphincter dysfunction, identified by sphincter electromyography and voiding cystourethrography, occurred in 20 per cent. Recognizing that identification of the underlying functional abnormality suggests a logical therapeutic approach, we recommend that all children with this symptom complex be studied urodynamically. In the event facilities to perform complete urodynamic studies are not available a case can be made for noninvasive screening to identify the hyperactive sphincter group, for this has the potential for being the most hazardous. This group can be identified by performing a uroflow electromyography study using stick-on electromyography electrodes and having the

URODYNAivIIC ABNOR.MALI'TIES

CHILDREN WITH M:liCTURJ:TION DYSFU1'1CTI0N

child void after a physiologic diuresis. If sphincter hyperactivity is demonstrated, referral for a more elaborate urodynamic study is recommended. With respect to the cystometric abnormalities that we have discussed, it is evident that the majority of cases are of bladder instability. Hence, after exclusion of the large capacity bladder by radiologic or instrumental techniques and after exclusion of sphincter hyperactivity the aforementioned noninvasive study, empiric treatment with anticholinergics would appear appropriate. We have stressed the problems of performance and interpretation of urodynamic studies in children but with experience reproducible and useful results can be achieved.

racy. J. 127: 736, 1982. 9. "Whiteside, C. and Arnold, E. P.: Persistent primary enuresis: a urodynamic assessment. Brit. Med. J., 1: 364, 1975. 10. Bauer, S. B., Retik, A. B., Colodny, A. H., Hallett, M., Khoshbin, S. and Dyro, F. M.: The unstable bladder of childhood. Urol. Clin. N. Amer., 7: 321, 1980. 11. Wein, A. J.: Pharmacologic approaches to the management of neurogenic bladder dysfunction. J. C. E. Urology, 18: 17, May 1979. 12. Koff, S. A., Lapides, J. and Piazza, D. H.: Association of urinary tract infection and reflux with uninhibited bladder contractions and voluntary sphincteric obstruction. J. Urol., 122: 373, 1979. 13. Koefoot, R. B., Jr., Webster, G. D., Anderson, E. E. and Glenn, J. F.: The primary megacystis syndrome. J. Urol., 125: 232, 1981.

REFERENCES 1. Cook, W. A., Firlit, C. F., Stephens, F. D. and King, L. R.:

2. 3. 4. 5. 6. 7.

8.

Techniques and results of urodynamic evaluation of children. J. Urol., 117: 346, 1977. Blaivas, J. G., Labib, KB., Bauer, S. B. and Retik, A. B.: Changing concepts in the urodynamic evaluation of children. J. UroL, 117: 778, 1977. Allen, T. D. and Bright, T. C., III: Urodynamic patterns in children with dysfunctional voiding problems. J. Urol., H9: 247, 1978. Webster, G.D. and Older, R. A.: Video urodynamics. Urology, 16: 106, 1980. Allen, T. D.: The non-neurogenic neurogenic bladder. J. Urol., 117: 232, 1977. Hinman, F. and Bauman, F. W.: Vesical and ureteral damage from voiding dysfunction in boys without neurologic or obstructive disease. J. Urol., 109: 727, 1973. Firlit, C. F., Smey, P. and King, L. R.: Micturition urodynamic flow studies in children. J. UroL, 119: 250, 1978. Koff, S. A. and Kass, E. J.: Abdominal wall electromyography: a noninvasive technique to improve pediatric urodynamic accu-

EDITORIAL COMMENT These investigators used urodynamic studies to evaluate a select group of children with urinary symptoms not easily diagnosable with radiographic studies or cystoscopy. Several patterns of voiding dysfunction were identified and these enabled the authors to recommend accurate treatment for the children. From this study and a similar study published several years ago (reference 13 in article) several syndromes of voiding dysfunction emerge. This study acknowledges the importance and selectivity of urodynamic studies in defining and managing children with dysfunctional voiding states. From these contributions we can understand some of the abnormalities of voiding that occur and sometimes persist into adulthood. By looking at specific groups intensely with urodynamic studies, as has been done by these investigators, we can become better clinicians in the future. Stuart B. Bauer Division of Urology Children's Hospital Medical Center Boston, Massachusetts