| Abstract|| |
Bladder instability simulating neurogenic bladder disease is one of the commonest causes of dysfunctional voiding in children. We studied 100 cases with such problem over a five-year period; the peak age incidence was between 4-8 years. The gender distribution was 3:2 with female preponderence. Urgency and urge incontinence occurred in 80% of cases, recurrent acute cystitis in 50%, characteristic-holding postures in 15% and nocturnal enuresis in 40%. Variable degrees of bladder wall thickening and significant residual urine were seen on ultrasound examination. The patients were given anticholinergic therapy and antibiotic prophylaxis. All the patients went into complete remission within five years, many of them earlier. None needed surgical intervention although few patients had undergone surgical vesicoscopy and urethral dilation before they were referred to us. We conclude that recognition of the children with bladder instability is paramount to successful management and this will help to avoid upper renal damage and reduce the discomfort from unnecessary investigations and surgical procedures.
Keywords: Children, Renal scarring, Bladder instability, Ultrasound, Anticholinergic therapy.
|How to cite this article:|
Aal AA, Khalil A. Bladder Instability and Upper Renal Tract Damage. Saudi J Kidney Dis Transpl 2004;15:463-7
| Introduction|| |
Bladder instability is believed to be caused by delayed disappearance of uninhibited contraction of bladder, which normally dissipates as it matures and adult voiding pattern is acquired. This condition is attributed to delayed maturation of the reticulospinal pathways in the spinal cord as well as the inhibitory center within the cerebral cortex. In turn, the sub cortical centers modulate medullary automatism. 
Many symptoms and signs of bladder instability are rooted in a faulty perception of signal from the bladder and consequently, the non-physiological response to the signals.  Bladder instability is usually manifested by urge incontinence, enuresis, recurrent lower urinary tract infections (UTIs), characteristic posture of holding, and varying degree of bladder wall thickening, as determined by ultrasonography.If bladder automatism is insufficiently inhibited, expulsive contractions of the bladder are likely to occur as a result of which constriction of the external urinary sphincter takes place. Thus, the child voluntarily tries to prevent wetting, a mechanism which causes high intravesical pressure.
Sometimes this mechanism may exceed 100 cm water.  The dominant force resulting from these combined activities will determine the type and degree of incontinence as well as causing abnormalities in the bladder such as trabeculations, sacculas, diverticula, reflux and upper tract damage. 
The clinical pattern of urge syndrome, staccato voiding, fractionated voiding, incomplete voiding, lazy bladder syndrome, and Heinman syndrome may all probably represent different stages in the natural histor1 of nonneuropathic bladder dysfunction.
The physical examination of such patients should include assessment of the spine for deformity, abdomen for signs of constipation and the lower extremities for neurological signs.  Not many publications have appeared over the past 10 years on this common problem, which comprises up to 20% of the out patient population of any pediatric nephrology service. 
Bladder instability is recognized as a significant cause of upper renal tract damage and early recognition, evaluation, and appropriate treatment could reduce unnecessary diagnostic and surgical procedures as well as reduce the incidence of upper tract damage.
| Materials and Methods|| |
We prospectively studied the first 100 patients referred from the primary care doctors, pediatric surgeons, and other pediatric consultants to the pediatric nephrology clinic in Salmania Medical Complex or Al Shefaa Pediatric Specialist Center in the year 1995. The patient inclusion criteria comprised a history of more than two months duration with two or more of the following symptoms: diurnal wetting, dribbling, urgency, frequency, dysuria and special postural holding of urine. Patients with neuropathic bladder disorder were excluded from the study.
| Investigations|| |
Midstream urine routine and culture and abdominal ultrasound were performed for all patients at the first visit. Additionally, micturating cystourethrogram (MCUG) was performed for those with pelvicalyceal dilation on ultrasonography as well as those who had recurrent UTIs in spite of antibiotic prophylaxis. Dimethyl succinic acid (DMSA) scan was performed for patients with vesicoureteric reflux seen on MCUG.
| Treatment|| |
All patients received anticholinergic therapy (Oxybutynin 0.4 mg/kg/day in two divided doses). Antibiotic prophylaxis with either cephalexin or nitrofurantoin once daily was given to patients with recurrent UTIs. DDAVP, 10 mcg nasally at bedtime, was given to those with nocturnal enuresis not controlled by oxybutynin. The medications were discontinued after three months and restarted if the symptoms recurred. All the patients were followed-up regularly in the clinic for the next five years.
| Results|| |
A total of 100 cases were studied. Females predominated (60%) with the maximum number of cases being in the ages of three and four years (22% and 40% respectively, [Figure - 1]).
Daytime dribbling was the main symptom occurring in 80% of the cases; urge incontinence and dysuria occurred in 50% of cases each. [Table - 1].
Ultrasonography was abnormal in 34% of cases. The commonest abnormalities seen included variable bladder wall thickening, pelvicalyceal dilatation and significant post void residual urine. [Figure1]
MCUG were performed on 24 cases; 20 patients showed bladder trabeculation and six showed vesicoureteric reflux (grades one to two). Two of these patients had associated sacculation and diverticulation. [Figure 2]
DMSA scan was performed on 20 cases of which six showed variable degrees of focal cortical scarring. [Table - 2]
All the patients were initially started on oxybutynin. In addition, 40 cases were given antibiotic prophylaxis, 18 received DDAVP, and 10 cases received lactulose for chronic constipation. [Table - 3].
All the patients went into complete remission within five years, many of them earlier. None needed surgical intervention although few patients had undergone surgical vesicoscopy and urethral dilation before they were referred to us.
| Discussion|| |
Bladder instability is the commonest voiding dysfunction encountered in children. The diagnosis is made easily by typical manifestation of urge incontinence with or without diurnal enuresis, recurrent UTIs, characteristic holding posture of urine and varying degrees of bladder wall thickening seen on ultrasonography.  The same diagnostic protocol was used in our study. The peak age incidence in our study was in age-group three and four years which is different from other studies where the five and seven years age-groups predominated. However, females predominated in the other study as well.  UTIs, which are common in bladder instability, reportedly occurs in 50 to 90% of affected patients and occurs mainly in girls while in our study, UTIs were seen in only 40% of the cases. ,
Treatment of bladder instability involves long-term usage of the anticholinergic oxybutynin, which is generally used for six to nine months.  We found that a trial with discontinuation of the drug every three months was successful in many and thus help in avoiding unnecessary prolonged therapy.
The best results are obtained when drugs are used in combination with bladder retraining, if the child has the cognitive capacity to understand what is taught and especially if an element of feedback can be incorporated into the retaining process. 
Nielson  found significant correlation between the severity of bladder instability and reflux nephropathy of grades three or above. In our study, we encountered reflux in six cases, all between grades one or two. Unfortunately, all of them showed varying degrees of cortical scarring. The reasons for this may be that the DMSA scan was performed early (within six months) after UTI or contributed to by a very sensitive gamma camera in our radiology department.
We need to repeat the scan in all such cases. Nevertheless, patients presenting with reflux and instability must be treated with antibiotic prophylaxis as well as oxybutynin, as the latter drug will lead to quicker reflux resolution.-  Reports on VUR and upper renal tract damage associated with bladder instability is varied with figures of between 33 and 50% being reported. , However, in our study only six percent of cases had both VUR and scarring.
This low figure could be attributed to early referral, recognition and treatment with anticholinergics with or without antibiotic prophylaxis as well as the due to the fact that the children were following a written program for retraining the bladder.
We conclude that recognition of the children with bladder instability is paramount to successful management and this will help in avoiding upper renal damage and reduce the discomfort from unnecessary investigations and surgical procedures.
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Abbas Abdul Aal
Consultant Pediatrician and Nephrologist, Salmania Medical Complex, P.O. Box.12, Manama
[Figure - 1]
[Table - 1], [Table - 2], [Table - 3]