Pediatr Surg Int (2000) 16: 569±572

Ó Springer-Verlag 2000

ORIGINAL ARTICLE

A. Alladi á S. Agarwala á A. K. Gupta á C. S. Bal D. K. Mitra á V. Bhatnagar

Postnatal outcome and natural history of antenatally-detected hydronephrosis

Accepted: 11 January 2000

Abstract Routine maternal ultrasonography (US) has revealed a very high incidence of fetal hydronephrosis (HDN), the postnatal outcome and management protocols of which are replete with controversies. Pelviureteric junction (PUJ) obstruction is the commonest postnatal diagnosis, and its management has no consensus to date. This study was carried out to de®ne the postnatal outcome and natural history of fetal HDN and to identify the mode of management to be adopted to the best advantage. All patients were subjected to US 48 h postnatally or at ®rst presentation and isotope renography (DTPA) with nuclear glomerular ®ltration rate (GFR) was carried out at 3±4 weeks of age or at presentation. Micturating cystourethrography (MCU) and/or direct radionuclide cystography (DRCG) were done in cases with bilateral HDN, nonobstructive HDN, dilated ureter on US, and recurrent urinary tract infection. Patients were then grouped for surgical intervention or conservative follow-up. Investigations were repeated periodically. A total of 56 patients were registered for the study (78 renal units) with a mean follow-up period of 14.6 months; 37 renal units were operated upon or scheduled for surgery and 67 had some organic pathology, of which PUJ obstruction was the commonest. Among patients with PUJ obstruction, indications for surgery included symptoms, a palpable mass, poor or deteriorating function, and a solitary functioning kidney. Patients operated upon showed A. Alladi á S. Agarwala á D. K. Mitra á V. Bhatnagar (&) Department of Paediatric Surgery, All India Institute of Medical Sciences, New Delhi-110029, India A. K. Gupta Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi-110029, India C. S. Bal Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi-110029, India

improvement in function and/or drainage, while those followed conservatively remained stable or improved. Controversy still exists as to the optimal management of PUJ obstruction detected antenatally. While it is the commonest postnatal diagnosis, many other pathologies are now being encountered. In antenatally-diagnosed HDN, there is a good scope for conservative management provided rigid follow-up can be ensured, especially because a good recovery potential exists followed surgery whenever indicated. Key words Antenatal hydronephrosis á Pelviureteric junction obstruction á Postnatal outcome

Introduction The widespread use of maternal ultrasound (US) has resulted in the detection of fetal hydronephrosis (HDN), which accounts for approximately 50% of all abnormalities detected by prenatal US [1, 2]. Postnatal diagnosis has added many new pathologies in addition to pelviureteric junction (PUJ) obstruction in recent years [3, 4]. The protocol of routinely operating upon infants with an antenatal diagnosis of PUJ obstruction was ®rst questioned in 1985 [5]. Subsequently, many reports of conservative management of such patients have appeared in the literature. Recently, a fresh controversy has erupted regarding the postnatal management of antenatally-detected HDN, one group advocating routine surgery and claiming the maximum potential for recovery in the ®rst 3 months of life [6, 7] and the other advocating conservative follow-up of all patients irrespective of initial renal function, reserving surgery only for those who show deterioration of function on follow-up or become symptomatic [8, 9]. Gradually, a sort of consensus has emerged whereby surgery is reserved for patients with symptoms and poor or deteriorating function while the others are followed up conservatively [10±13]. This

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prospective study was carried out to assess the postnatal outcome and identify the mode of management to be adopted for maximum advantage.

Materials and methods A prospective study was carried out over a 3-year period from 1995 to 1998. All patients were registered in the Paediatric Urology Clinic. Baseline postnatal real-time B-mode US was carried out using a 3.5, 5, or 7 MHz convex or linear transducer on the UM 9HDI (ATL) or Acuson 128´ P10 machine 48 h after birth or at initial presentation if the patient was referred later. Diuretic isotope renography with nuclear glomerular ®ltration rate (GFR) was carried out at 3±4 weeks of age or at initial presentation using a LFOV gamma camera set up with a LEAP collimator with an online micro-delta Siemens computer. Data acquisition started immediately after a bolus injection of 7.4 MBq technetium Tc99m diethylene triamine penta-acetic acid (DTPA) and recorded in a frame mode ± 1/s frame for the ®rst 40s followed by 1 frame/10 s for 20 min. Furesmide 1 mg/kg was given IV 20 min after the start of the study. Delayed images were taken at 3 and 24 h. GFR was estimated using the single-injection, single-compartment technique and ranged from a minimum of 2 samples at 1 and 3 h to a maximum of 5 samples at 1/1.5/2/2.5/3 h. Micturating cystourethrography and/or direct radionuclide cystography was carried out in patients with bilateral HDN, nonobstructive HDN, dilated ureters on US, and recurrent urinary tract infections. If further clari®cation was required, computed tomography, antegrade pyelography, and cystoscopy were carried out. Based on the results of the above investigations, the patients were grouped for surgical intervention or conservative follow-up. The investigations were repeated at 3-monthly intervals. Indications for surgical management were PUJ obstruction in a solitary kidney, PUJ obstruction with poor or deteriorating function, and symptomatic PUJ obstruction. Poor function was de®ned as less than 40% of the di€erential function in unilateral obstruction or a GFR less than expected for age in bilateral obstruction. Deterioration in function was taken as a fall in di€erential function by more than 5% or increasing degree of hydronephrosis with thinning of the renal cortex. Other pathologies were operated upon or followed up according to the diagnosis.

Results A total of 56 patients were registered; 22 had bilateral pathology. Hence, a total of 78 renal units were available for review. Males were four times more often affected than females. The follow-up period ranged from 2.5 to 36 months (mean 14.6 months). The age at presentation ranged from antenatal to 8 months of age. Except for 1 patient with a unilateral multicystic kidney (MCK) and 1 with bilateral hydroureteronephrosis, all antenatal scans had detected only HDN. PUJ obstruction was the commonest pathology, accounting for 50% of cases. The remaining 50% were a combination of other uropathies, e.g., nonobstructive HDN, vesicoureteric re¯ux (VUR), posterior urethral valves (PUV), MCK disease, etc; 86% had some organic pathology, and a total of 36 units (47%) needed surgery (Table 1). The indications for surgery in PUJ obstruction varied (Table 2). The age at surgery ranged from 1 to 21 months. The postoperative results in 20 PUJ-obstructed patients (mean follow-up 5 months) showed signi®cant

Table 1 Postnatal diagnoses in 56 patients (78 renal units) Diagnosis

No. of units (%)

Pelviureteric junction obstruction Idiopathic nonobstructive hydronephrosis Vesicoureteric re¯ux Multicystic kidney Nonfunctioning kidney Vesicoureteric junction obstruction Miscellaneous Duplex system Ureterocele Posterior urethral valves Prune-belly syndrome Ureteric stenosis Normal kidneys

39 (50.0) 11 (14.2) 6 4 3 2

(7.7) (5.1) (3.8) (2.6)

3 1 2 2 1 4

(3.8) (1.3) (2.5) (2.5) (1.3) (5.1)

Table 2 Indications for surgery in 20 patients with pelviureteric junction obstruction Indications

No. of cases (%)

Symptomatic patients Presence of lump Poor function on presentation Deterioration on observation Solitary kidney

4 2 9 1 4

(20.0) (10.0) (45.0) (5.0) (20.0)

improvement in drainage in all cases and improvement in function in 6. The improvement in di€erential function ranged from 12% to 27%. Patients who were followed conservatively showed improvement in function and/or drainage or remained stationary (Figs. 1 and 2). Of the 5 patients with VUR, which ranged from grades 2 to 5 and was uni- or bilateral, 3 required surgery for persistent symptoms or high-grade re¯ux. Other patients falling into the surgically-managed group include 4 with multicystic dysplastic kidneys, 2 with vesicoureteric junction obstruction, and 1 each with PUV, prune-belly syndrome, ureteric stenosis, and duplex system with ureterocele (Table 3).

Fig. 1 Changes in di€erential renal function with increasing age following pyeloplasty and during conservative follow-up

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Fig. 2 Ipsilateral renal function (DTPA scan) and contralateral renal length (index of renal growth measured by US) in unilateral hydronephrosis with initially poor function. Postoperative improvement in ipsilateral renal function produces corresponding slowing of contralateral renal growth

Discussion The enlarging pool of antenatally-diagnosed HDN represents a di€erent group of anomalies, the natural history of which remains to be de®ned. The optimal management protocol to be followed is still controversial, and the debate continues. Earlier reports found antenatally-detected HDN to be either due to PUJ obstruction or idiopathic postnatally. However, many other uropathies Table 3 Outcomes in various conditions (n = 20)

have recently also been reported [1, 14±18]. The present study compares with these in that only 50% of cases were due to PUJ obstruction, while the remaining cases included a host of other uropathies (Table 4). The main controversy applies to the postnatal management of PUJ obstruction diagnosed antenatally. King and Hatcher [6] recommended immediate pyeloplasty since contralateral hypertrophy began quickly after birth and surgical relief of obstruction allowed the maximum potential for recovery of the a€ected kidney. On the other hand, Ko€ and Campbell [8, 9] held a radically opposing view, advocating conservative followup of all patients irrespective of their initial di€erential function in unilateral obstruction. In the present series, in at least 3 patients who had poor function in the a€ected kidney a compensatory accelerated growth rate was observed, while in those with well-maintained function there was no evidence of compensatory hypertrophy. Spontaneous resolution on follow-up has varied in di€erent studies. In the present series, while only 3 of 19 cases showed resolution of obstruction and HDN, 8 showed a reduction in HDN. None of the renal units with a di€erential function above 40% have shown any deterioration. The usefulness of isotope renography in diagnosing obstruction has been questioned due to tubular immaturity in the ®rst 2 years of life [10]. This results in a high urine ¯ow rate, which may not allow any reserve for the e€ect of a loop diuretic. The signi®cantly improved response to drainage and diuretics postoperatively in the

Diagnosis

Operated or planned for surgerya

Observed

Total

Pelviureteric junction obstruction Hydronephrosis Vesicoureteric re¯ux Multicystic kidney Vesicoureteric junction obstruction Nonfunctioning kidney Normal Posterior urethral valves Prune-belly syndrome Ureteric stenosis Duplex Ureterocele

20 0 4 4 2 0 0 2 2 1 1 0

19 11 2 0 0 3 4 0 0 0 0 3

39 11 6 4 2 3 4 2 2 1 1 3

a

(51.3) ± (66.6) (100) (100) ± ± (100) (100) (100) (100) ±

(48.7) (100) (33.3) ± ± (100) (100) ± ± ± ± (100)

Figures in parentheses indicate percentage

Table 4 Postnatal pathologies encountered in di€erent series

Total no. of units Pelviureteric junction obstruction Hydronephrosis Vesicoureteric re¯ux Vesicoureteric junction obstruction Multicystic kidney Posterior urethral valves Miscellaneous Normal

Turnock

Flynn

Podevi

Kim

Dudley

Raded

Crignon

Present series

24 12 ± ± ± ± 10 11 ±

335 73 85 21 ± 48 16 58 ±

103 17 ± 15 ± ± ± ± 11

48 13 16 2 4 ± 2 6 ±

100 ± ± 12 ± ± ± ± 36

123 48 ± 15 18 13 ± ± 29

39 30 ± 3 1 21 2 ± 1

78 39 11 6 2 4 1 11 4

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present series in children aged less than 6±12 months refutes the above reasoning. In conclusion, controversy reigns as to the optimal management and natural history of antenatally-detected HDN. While PUJ obstruction continues to be the commonest pathology, many other causes are now being encountered. A high scope for conservative management exists provided strict follow-up can be ensured. Patients with unilateral PUJ obstruction with a di€erential function of less than 40% should be operated upon at the earliest possible time, while those with above 40% di€erential function or bilateral pathology with stable GFR and no deterioration on follow-up can be safely followed conservatively.

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