Normal growth with renal insufficiency owing to posterior urethral valves: value of long-term diversion. A twenty-year follow-up

Long-term growth in children with posterior urethral valves

BACKGROUND

Posterior urethral valves (PUVs) are one of the leading causes of pediatric chronic kidney disease (CKD). Growth impairment is prevalent in pediatric CKD, and children with PUVs are at high risk for growth retardation.

OBJECTIVE

The objective of this study was to describe growth profiles in PUVs and to identify risk factors for stunting, defined as age-specific height standard deviation score (SDS) below -2.

PATIENTS AND METHODS

Medical records of 65 patients with PUVs and a minimum follow-up of two years were retrospectively reviewed. Chronic kidney disease stage 1-3 was considered mild CKD, whereas CKD stage 4-5 was considered advanced CKD. Age-specific height, weight, and body mass index (BMI) SDS were determined. Seven potential risk factors for stunting, namely timing of diagnosis, renal dysplasia, timing of surgery, requirement of urinary diversion, nadir serum creatinine after surgery, recurrent febrile urinary tract infection (UTI), and severity of CKD, were analyzed.

RESULTS

Median age at diagnosis, at surgery, and at last follow-up was 0.51, 0.75, and 7.53 years, respectively. All patients underwent valve ablation, and 33.8% required urinary diversion. Median nadir serum creatinine after surgery was 0.40 mg/dL and was higher in patients who underwent urinary diversion (P < 0.001). Growth profiles by CKD stage are displayed in Fig. 1. Median height SDS was -0.40 and was lower in patients with advanced CKD (P = 0.03). Stunting was diagnosed in 15.4%. Advanced CKD was an independent risk factor for stunting, with the odds ratio of 12.7. Urinary diversion and nadir creatinine more than 0.80 mg/dL were weakly associated with stunting but not significant. Timing of diagnosis and surgery, unilateral renal dysplasia, and recurrent febrile UTI were not associated with stunting. Median SDS of weight and BMI was -0.64 and -0.19, respectively. Patients who were thin, of normal weight, overweight, and obese comprised 26.2%, 58.5%, 10.8%, and 4.6%, respectively. There was no significant difference of SDS of weight and BMI across CKD stages (Fig. 1).

DISCUSSION

Deterioration in height began early in the course of disease and was worsening in relation to the decline of renal function. The impact of timing of diagnosis or surgery on height was controversial. Patients who underwent urinary diversion had high nadir creatinine and were likely to have severe PUVs. Although patients with severe baseline renal dysfunction may require urinary diversion, nadir serum creatinine and urinary diversion are not associated with stunting. Delaying progression of CKD could maximize linear growth potential in PUVs. A substantial proportion of patients were overweight or obese. Sufficient caloric intakes may be maintained in patients with PUVs.

WHEN CAN PERSISTENT HYDROURETERONEPHROSIS IN POSTERIOR URETHRAL VALVE DISEASE BE CONSIDERED RESIDUAL STRETCHING?

PURPOSE

Persistent hydroureteronephrosis (HUN) is often seen in boys with a history of a posterior urethral valve even years after valve ablation and it is often assumed to represent residual stretching. We determined the association of HUN with urodynamic abnormalities, the effect on HUN of treating these abnormalities and when persistent HUN could be considered residual stretching.

MATERIALS AND METHODS

Of 71 patients with a posterior urethral valve evaluated after valve ablation 20 (28.2%) had persistent HUN in a total of 32 renal units (RUs). The degree of HUN was graded as mild, moderate or severe. Videourodynamics were performed in all patients with persistent HUN and abnormal urodynamic findings were aggressively treated. HUN was then reassessed and categorized as resolved, improved or unchanged.

RESULTS

Abnormal urodynamic findings, primarily hypocompliance and instability, were noted in all 20 patients with HUN. All patients compliant with treatment showed dramatic improvement or complete resolution of abnormal urodynamic parameters. The 32 RUs with persistent HUN were initially graded as mild (8), moderate (13) and severe (11). HUN resolved in 15 RUs and improved to a lower grade in 11 in 26 of the 27 RUs (96.3%) in the 17 patients compliant with treatment. The 3 boys (5 RUs) who were noncompliant with treatment had neither decreased HUN nor improved urodynamic parameters. The 12 of 27 RUs (44.4%) in the treatment group in which HUN failed to resolve completely had no distal ureteral obstruction or identifiable persistent urodynamic abnormality and, thus, they can be labeled as having residual stretching.

CONCLUSIONS

Persistent HUN following valve ablation should not be considered residual dilatation until a thorough urodynamic evaluation has been done and any abnormal parameters are addressed. With correction of these abnormal parameters one can expect significant lessening of HUN and hopefully improved long-term preservation of renal function.

DOES MODE OF TREATMENT AFFECT THE OUTCOME OF NEONATAL POSTERIOR URETHRAL VALVES?

PURPOSE

A prospective study on the outcome of posterior urethral valves (PUV) was performed. The data analyzed were whether the modality of treatment (fulguration vs vesicostomy) affected renal function and somatic growth, and whether the presence of vesicoureteral reflux (VUR) and abnormal serum creatinine levels affected somatic growth.

MATERIALS AND METHODS

A total of 45 consecutive neonates were diagnosed and treated for PUV with fulguration (24) or vesicostomy (21) between 1997 and 2003. Postoperative stable creatinine values, renal function and somatic growth were recorded. Well tempered renal scans using diethylenetetraminepentaacetic acid were performed during the first and second years of life at followup. Standard anthropometric techniques and statistical methods were used to compute distance statistics for body weight and crown-heel length at age intervals of 3 months for year 1 and 6 months for year 2.

RESULTS

Of the patients 9 were lost to followup and 6 died in the first year of life due to renal failure. Preoperative and postoperative mean serum creatinine was 1.6 +/- 1.5 and 0.7 +/- 0.2 mg/dl, for the fulguration group and 1.7 +/- 1.5 and 0.9 +/- 0.7 mg/dl, respectively, for the vesicostomy group. In 10 patients renal function deteriorated or there was no improvement after treatment. With the advancement of age neonates with PUV showed normal increase in body weight and crown-heel length. Those with VUR were significantly shorter compared to neonates with no VUR at the end of year 2 of life (p <0.05). Patients with creatinine less than 1 mg/dl had significantly greater increase in body weight (at 3 and 6 months) as well as crown-heel length (at 3 and 9 months), respectively (p <0.05). Physical growth of the fulguration and vesicostomy groups remained substantially lower than that of their normal healthy counterparts. Newborns treated with vesicostomy did not have any breakthrough urinary tract infections. Although patients treated with vesicostomy were lighter and smaller initially (p <0.05), they were comparable to those treated with fulguration at the end of 2 years, thus demonstrating catch-up growth.

CONCLUSIONS

Our prospective study demonstrated that transurethral fulguration and vesicostomy are equally effective for neonatal valves and achieve similar renal function. Both groups showed retarded growth compared to healthy counterparts. Somatic growth was delayed by serum creatinine greater than 1.0 mg/dl and the presence of VUR. Vesicostomy seemed to help neonates catch-up the growth deficit in the first 2 years of life.

Does Treatment With Clean Intermittent Catheterization in Boys With Posterior Urethral Valves Affect Bladder and Renal Function?

PURPOSE

In boys with resected posterior urethral valves (PUV) deterioration of renal function is seen during childhood and adolescence, which may partly be caused by bladder dysfunction. We present data on renal and bladder function initially and at followup of boys with PUV in whom the bladder dysfunction has been treated since infancy.

MATERIALS AND METHODS

The study included 35 boys with PUV. Bladder regimen, including early toilet training from the age of 1.5 years and detrusor relaxant drugs for the treatment of incontinence from ages 4 to 6 years, was introduced to all patients. A total of 19 boys were started on clean intermittent catheterization (CIC) at a median age of 8 months due to pronounced bladder dysfunction with poor emptying, unsafe pressure levels, high grade reflux and renal impairment.

RESULTS

No serious complications of CIC have been seen during followup. Of the 19 boys 2 stopped performing CIC due to noncompliance of the parents at 1 and 3 years, respectively. Initial renal function, measured as median glomerular filtration rate (GFR) in percent of expected for age, was 60% in the CIC group and 90% in the nonCIC group. At followup at a median age of 8 years the CIC group (n = 14, 3 transplanted boys excluded) had an increase in median differential GFR (difference between followup and initial GFR) of 7% (p <0.01), which was similar increase to that of the nonCIC group. In the 2 boys who stopped performing CIC renal function deteriorated with a median differential GFR of -24%. In the CIC group detrusor instability decreased. Poor compliance was seen in 6 of the 19 boys initially and only one remained poorly compliant. In 1 of the boys who stopped performing catheterization a low compliant bladder developed. In all of the other cases bladder capacity increased more than expected for age.

CONCLUSIONS

The results suggest that treatment of bladder dysfunction in boys with PUV can counteract the deterioration in renal function seen during childhood but the number of patients in our study is limited.