PRENATAL
HYDRONEPHROSIS
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MÁRCIO L. MIRANDA, LOURENÇO SBRAGIA, ANTÔNIO A. MELO FILHO, HUGO F. KÖHLER, RICARDO BARINI, JOAQUIM M. B. SILVA
Division of Pediatric Surgery, Department of Surgery, and Department of Obstetrics and Gynecology, School of Medicine, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
ABSTRACT
Objective:
To report the experience of the Fetal Medicine Group of the State University
of Campinas Medical School with the diagnosis and management of intrauterine
hydronephrosis.
Patients and Methods: From January 1997
to April 1999, forty-five women, whose fetuses were diagnosed with prenatal
hydronephrosis were treated by the Fetal Medicine Group.
Results: Thirty-one fetuses were male, eleven
were female and three had undetermined gender. Nineteen fetuses (42.2%)
had additional malformations. Prenatal intervention was performed in 18
fetuses, being 18 urine aspirations and three shunt placement. Mean birth
weight was 2,778 g. There were eleven deaths that occurred either intrauterine
(# 4) or in the immediate postnatal period (# 7). Thirty-four neonates
were followed, whose final diagnoses was transitory hydronephrosis in
three neonates (8.82%), ureteropelvic junction obstruction in nine (26.5%),
non-obstructive hydronephrosis in four (11.8%), vesicoureteral reflux
in seven (20.6%), ureterovesical junction obstruction in five (14.7%)
and posterior urethral valve in six (17.6%). The 31 with non-transitory
hydronephrosis were closely monitored after birth for a mean follow-up
of 16.8 months (6 to 37 months). Seventeen children (54.8%) in whom renal
function remained within normal limits were treated non-operatively. The
remaining 14, whose renal function was either initially poor or deteriorated
during follow-up, underwent surgical correction of their anomalies.
Conclusions: Antenatal diagnosis of hydronephrosis
allows early follow-up by a multidisciplinary team, improving the management
of these infants and eventually providing the rationale for early intervention.
Key words:
kidney; hydronephrosis; prenatal diagnosis; fetus; ultrasonography
Braz J Urol, 28: 147-153, 2002
INTRODUCTION
The
routine use and improvement of prenatal ultrasonography allowed early
diagnosis and therapeutic planning of pregnant women carrying fetuses
with congenital anomalies, such as urinary anomalies (1). Fetuses with
prenatal disgnosis of hydronephrosis can present normal renal growth and
function, independent of the fetal intervention. However, non-treated
fetuses with obstructive bilateral uropathies can develop progressive
renal function deterioration, oligohydramnios and prenatal death (2).
Prenatal diagnosis of hydronephrosis enables
either the follow-up of urinary anomalies as fetal interventions, mainly
in bilateral cases. The ultimate aim is to preserve postnatal renal function
and change the development of obstructive uropathies (2).
The present study reports the experience
of Unicamp Fetal Medicine Group in the management of prenatally diagnosed
hydronephrosis and its postnatal follow-up.
PATIENTS AND METHODS
From
January 1997 to April 1999, 45 pregnant women whose fetuses suffered from
uni- or bilateral hydronephrosis were treated. The anomalies were diagnosed
through prenatal ultrasonography performed by the physicians from the
Center of Integrated Attention to Women Health - Unicamp. Unicamp Fetal
Medicine group, responsible for pregnant women entire follow-up, is formed
by a multiprofessional team with obstetricians, neonatologists, pediatricians,
neurosurgeons, geneticists and pediatric cardiologists, besides psycologists,
social assistants and nurses.
Medical register data in the present study
were: 1)- prenatal ultrasonography information, such as gestational age
at the moment of the diagnosis of hydronephrosis; fetal gender; presence
of associate malformation; amniotic liquid measured through the amniotic
liquid index, which indicates the normal amount of liquid for each gestational
age; presence of cysts or alterations in renal echogenicity; performance
of fetal urinary tract puncture and evaluation of fetal urinary function
through electrolytes determination; indication of fetal urinary diversion
and pregnancy outcome, and 2)- neonatal information; birth weight; gender;
ultrasonography and voiding urethrocystography and scintigraphic tests
of DTPA and DMSA for renal function quantification and posterior neonatal
diagnostic confirmation; clinical or surgical treatment and total follow-up
duration.
Prenatal ultrasonography has allowed the
routine measurement of the amniotic liquid in all pregnant woman. It has
also guided the urinary tract puncture. Puncture to collect fetal urine
was indicated in the following conditions: bilateral hydronephrosis and
presence of oligohydramnio or progressive reduction of amniotic liquid.
Intrauterine derivation (vesicoamniotic) was indicated to fetuses with
favorable prognosis, defined by Harrison et al. (2) as: pregnancy between
20 and 30 weeks without associate malformations and with normal karyotype,
urinary levels of sodium < 100mEq/ml, of chlorine < 90mEq/ml, b2-microglobulin
< 2 mg/dl and osmolarity < 210mOsm.
During the first month after birth, the
cause of hydronephrosis was investigated through ultrasonography and voiding
urethrocystography. Newborns with normal ultrasonography and voiding urethrocystography
were re-evaluated by the age of 3 months, to confirm the transitory hydronephrosis
diagnosis or to identify any urinary deviation which could have been incorrectly
diagnosed. The initial approach was conservative and included urinary
tract cyntilographic evaluation with DMSA and/or DTPA one month after
birth. All newborns were initially treated with antibiotic prophylaxis
until diagnostic definition. Antibiotics were continued in cases of confirmed
hydronephrosis.
Surgical treatment was indicated when bilateral
ureteropelvic junction obstruction, superior tract obstruction on DTPA
and renal tubular function deterioration on DMSA, and superior urinary
tract infection, independently of the use of antifioticprophylaxis, were
observed.
RESULTS
The
mean gestational age at the time of the intrauterine diagnosis was 28.2
weeks (16 - 38). In 20 patients the hydronephrosis was identified before
26 weeks. Nineteen fetuses (42.2%) presented with associate malformation.
Cordocentesis was performed in 15 to identify chromosopaties. Gender was
identified in 42 fetuses, being 31 males, 11 females and 3 not-determined.
Initial echographic evaluation reveled normal amniotic liquid in 35 (77.8%),
lower in 7 (15.5%) and higher in 3 (6.7%) fetuses. Most fetal kidneys
did not present renal parenchima ecogenicity alterations (75.6%) and only
9 presented renal cysts (20.9%).
Fetal urine collection was performed in
18 women, being 15 from the fetal bladder and 3 from the renal pelvis.
Six of the punctured fetuses died. Four of them presented severe oligohydramnios,
elevated b2- microglobulin (mean of 26.4 mg/dl) and sodium and chlorine
higher than 100 mEq/ml. The 12 punctured fetuses who survived presented
urinary sodium and chlorine levels below 100 mEq/dl. b2 microglobulin
was performed in only 6 of the latter (mean of 3.5 mg/dl).
Vesicoamniotic deversion was performed in
3 fetuses to diminish the urinary tract pressure. One diversion was successful
and resulted in hydronephrosis alleviation. The other 2 fetuses were born
prematurely, one after the migration of the amniotic liquid catheter to
the fetal peritoneum.
Thirty-four fetuses survived and 11 died. Four or the latter died intrauterus
(36.3%) and 7 in the immediate postnatal period (63.7%). From the ones
who died, 10 presented other associate malformations, 7 confirmed by necropsy
(4 congenital cardiopaties and 3 central nervous system malformations).
There was no relation between fetal or neonatal death with fetal puncture
or deversion. Mean birth weight of the 34 newborns who survived was 2,778
g (1,140 g – 4,390 g).
Neonatal confirmation of the diagnosis reveled
3 cases of transitory hydronephrosis (8.8%), 6 cases of ureteropyelic
junction anomalies (17.6%), 3 cases of ureteropyelic junction anomalies
associated with contralateral non-obstructive hydronephrosis (8.8%), 4
cases of non-obstructive hydronephrosis (11.8%), 7 cases of primary vericoureteral
reflux (20.6%), 5 cases of megaureter without reflux (14.7%), 5 cases
of posterior urethral valve (14.7%) and 1 urethral stenosis (3%).
Prenatal ultrasound diagnosis was not in
accordance with the neonatal ultrasound diagnosis in 6 out of the 21 patients
(87% of sensibility), whose prenatal ultrasonography showed bilateral
hydronephrosis. The neonatal ultrasound was normal in 3 of these children
and showed unilateral hydronephrosis in the others (Table-1).
From the 9 neonates with final diagnosis
of ureteropyelic junction anomaly, 7 (77.8%) were male, and 8 (88.9%)
presented unilateral impairment of the renal function. There was an association
with contralateral non-obstructive hydronephrosis in 3 neonates (33.3%).
From the 7 neonates with primary vesicoureteral reflux, 4 (57.1%) were
male and 5 (71.4%) presented unilateral impairment of the renal function.
Among the patients with infravesical obstruction (posterior urethral valve
or urethral stenosis), 3 presented vesicoureteral reflux and significant
unilateral renal deterioration. One of them had patent urachus at birth.
After diagnosis confirmation, 17 newborns
(50%) with normal renal function were clinically treated, with no need
of surgical intervention. During the entire clinical follow-up, the renal
function did not present any alteration. In contrast, 14 newborns (41.2%)
were operated due to abnormal renal function (Table-2).
The initial presentation of six out of 14
patients who were operated was low unilateral renal function, which was
secondary to the ureteropyelic junction anomaly in 5 of them, and secondary
to the obstructive megaureter in one. From these, 4 were submitted to
nephrectomy due to renal exclusion and 2 were submitted to pyeloplasty,
at 2 and 8 months of life, respectively. As for the 2 patients operated
with bilateral ureteropyelic junction obstruction, one had no problems
during follow-up while the other, with low renal function since diagnosis,
presented deterioration of the renal function and recidive of obstruction.
He was submitted to endopyelotomy without any sign of obstruction after
6 months. However, the renal function remained low.
Two patients with vesicoureteral reflux
and unfavorable outcome in the clinical treatment were operated. The first,
with recurrent urinary tract infection, had the ureter reimplantated by
Politano technique at the age of 9 months, with no incidents. The second,
with cloaca extrophy, was submitted to a step-by-step treatment , with
vesicostomy at birth and ureteral reimplantation afterwards, dying at
the age of 12 months due to urinary sepsis.
The results of the 6 patients with infravesical
obstruction are as follows: the initial postnatal treatment were vesicostomy
followed by posterior urethral valve ablation in 5 and early valve resection
in one. All patients with infravesical obstruction had preserved renal
function. This group includes the 3 patients who were submitted to intrauterine
vesicoamniotic diversion.
The mean follow-up of the 31 patients with
neonatal urinary abnormality was 16.8 months (6 - 37 months).
DISCUSSION
Hydronephrosis
is the most frequent alteration detected by prenatal ultrasonography,
with a global incidence of 1% in the fetal diagnosis. It corresponds to
approximately 50% of all anomalies detected intrauterus. Prenatal identification
has significantly increased with the advent of detailed fetal ultrasonography
as from 18 - 20 weeks of pregnancy and with the improvement of its resolution
(1).
Early hydronephrosis identification allows
the screening of fetuses with indication of prenatal intervention, delivery
anticipation, or anticipated removal to a specialized medical service.
Besides being important to family counseling, it allows better parents’
orientation and preparation to the diagnosis and eventual pre- or postnatal
intervention.
Early perinatal medical follow-up of patients
with hydronephrosis avoid urinary tract infections in newborns at risk,
decrease hospitalizations due to infections or electrolytic dysfunction,
and enable the substitution of urgent for elective surgeries. However,
there are still some doubts regarding the significant improvement in the
incidence of chronic renal failure at adult age (3).
Many parameters aid in the ultrasonographic
diagnosis of fetal hydronephrosis. The anteroposterior diameter of the
renal pelvis is considered the most simple and sensitive. Corteville et
al. (4) believe that a pelvis diameter ³ 4 mm and ³ 7 mm before
and after the 30th week of pregnancy, respectively, are associated with
high diagnostic sensitivity. Even though their data are consistent, it
is still controversial if the dilation degree at birth can predict postnatal
hydronephrosis development.
Antenatal intervention is still not a consensus
in fetal hydronephrosis approach, especially regarding nephro- and vesicoamniotic
diversions with the purpose of preserving postnatal renal function.
The last 10 years are characterized by the
refinement in fetal therapy. The treatment philosophy defined the prevention
of lung hypoplasia as the primary purpose, being secondary the effects
on renal and vesical function.
In order to identify the fetuses who will
really benefit from intrauterine urinary deversions, the selection criteria
was refined. This is based on amniotic liquid quantification (amniotic
liquid index measured by ultrasonography), karyotype study and fetal urine
electrolytes and protein dosage (5).
The serial evaluation of fetal urine has
been postulated for allowing a better accurate selection of fetus who
will benefit from urinary diversion (6). The addition of new fetal renal
function prognostic markers has aided urinary investigation. The a1-microglobulin,
the growth transformation-b1 factor and the epidermic growth factor are
some of them (5). In the present study, we observed that proteinuria as
demonstrated by b2 microglobulin dosage has been a bad prognosis indicator,
mainly when associated with elevated concentration of sodium and chlorine
in the fetal urine.
Advances in the techniques for fetal urinary
diversion have allowed safer procedures with low complication rates. The
most frequent complications are the migration of the diversion catheter
to a site outside the bladder, with fetal urinary ascites formation or
intestinal herniation, and the subsequent obstetric complications (5,7).
Freedman et al. compared fetuses in similar circumstances with or without
vesicoamniotic diversion. They showed significant decrease in the number
of intrauterus deaths, even though there was an increase in the incidence
of early labor (5).
In the present study, two out of three diversions
resulted in early labor. One of them occurred after catheter migration
and formation of urinary ascites.
In our experience, the best criteria to
indicate fetal urine collection has been the progressive decrease in the
amniotic liquid index or severe oligohydramnios.
The most common causes of fetal hydronephrosis
are transitory non-obstructive factors such as the physiologic dilation
(8). The low incidence of transitory hydronephrosis is noticeable in our
casuistics. This is possibly due to the fact that, as a tertiary service,
we follow a high number of pregnant women with high risk of significant
fetal anomalies. This fact can equally explain the high mortality rate
in the immediate antenatal or neonatal period (24.4%), because almost
all patients (90.9%) presented with associate malformations.
The ureteopyelic junction anomaly is the
main cause of neonatal hydronephrosis. It occurs mainly because of abnormal
distribution of collagenous and musculary fibers in this region (9). It
is more common in males, being bilateral in 21 to 36% of the cases (10).
The prenatal diagnosis of ureteropyelic
junction anomaly has motivated the creation of 2 therapeutic approaches:
one that advocates early surgical correction, and another that advocates
close surveillance with surgery being indicated only in cases of renal
function deterioration. The initial renal damage is smaller in cases detected
in the prenatal period; however, there is no consensus in the literature
if there will be a renal function improvement after early pyeloplasty
when compared to children with later diagnosis and surgery (11,12).
In our study, the surgical intervention
was performed only in those patients who presented obstructive DTPA with
low initial relative tubular renal function (< 40%), significant decrease
(³ 10%) during follow-up, outbreak of new scars or recurrent urinary
tract infection. The 2 children submitted to pyeloplasty in this series
presented bilateral ureteropyelic junction anomaly and low initial tubular
function.
Vesicoureteral reflux develops in 10 to
25% of the prenatal hydronephrosis. Normal postnatal ultrasonography is
seen in 18 to 30% of them. It is more common in boys, there is higher
incidence of bilateral onset, and the reflux grade is more severe (13).
It is possible that such characteristics are secondary to high intravesical
pressures, due to late maturation of the striate urethral sphincter in
boys, as described by Kokoua et al. (14). In spite of controversial, the
performance of postnatal voiding ureterocystography is advocated in all
cases of ante- or postnatal hydronephrosis to diagnose vesicoureteral
reflux (8,15).
The impact of prenatal diagnosis in the
vesicoureteral reflux outcome is still not known. Due to the frequent
spontaneous resolution of early diagnosed reflux, our approach has been
conservative, with clinical surveillance, antibiotics prophylaxis and
selected tests for renal evaluation.
Ureterovesical junction anomalies characterize
the megaureter in its different forms as follows: non-refluxive / non-obstructive,
obstructive and refluxive different forms. Spontaneous improvement of
the megaureter is a common event. Prenatal diagnosis allows early follow-up
and identification of some patients who can develop renal function deterioration,
despite the absence of symptoms (9). In the present study, 4 out of 5
newborns with non-refluxive megaureter diagnosis were conservatively treated.
The posterior ureteral valve is the most
common cause of infravesical obstruction in boys, with an incidence of
1 in 4,000 to 25,000 children born alive (9). The presence of a fetus
with thick bladder wall, bilateral hydronephrosis, with or without renal
dysplasia, and oligoamnio strongly suggests the prenatal diagnosis of
posterior ureteral valve.
There are three anatomic variables associated
with the posterior urethral valve in fetuses which acts as a escape valve
mechanism reducing high urinary system pressure and preserving renal function.
They are the posterior urethral valve syndrome, characterized by unilateral
vesicoureteral reflux and renal dysplasia, congenital vesical diverticulum,
and urine leakage, for example, secondary to uracus patency. Rittenberg
et al. (16) have shown differences in the serum creatinine among boys
with or without escape valve. Among the 6 fetuses with infravesical obstruction
in our casuistics, 4 presented escape mechanisms (3 with posterior valve
syndrome and dysplasia, and one with uracus patency).
In order to preserve bilateral renal function
secondary to urethral obstruction, the main indication of fetal urinary
diversion has been the progressive decrease in the amniotic liquid index
or oligodramnio, associated with preserved fetal renal function as measured
by urinary biochemistry, absence of other significant abnormalities and
normal fetal karyotype. Although the diversion is a therapeutic maneuver
to preserve the fetus renal function, its long-term benefit is not completely
known (17). In this series, 3 out of 6 fetuses with infravesical obstruction
were submitted to intervention.
The neonatal treatment of choice for posterior
urethral valve is the endoscopic ablation of the valve (18). After the
acquisition of endoscopic instruments for posterior urethral valve resection,
we have also adopted such approach (19).
The development of the fetal surgery by
uterine laparoscopy and fetal cystoscopy with laser-assisted posterior
ureteral valve ablation has been described as a promising technique (20).
Such procedure could avoid intrauterus diversion, as well as offer earlier
obstruction relief (18).
We can conclude that the prenatal diagnosis
of hydronephrosis allows perinatal follow-up which results in an appropriate
posnatal management, especially in patients with hydronephrosis. As a
consequence, it helps in the selection of patients who will eventually
need early surgical intervention.
REFERENCES
- James CA, Watson AR, Twining P, Rance CH: Antenatally detected tract abnormalities: changing incidence and management. Eur J Pediatr, 157: 508-511, 1998.
- Glick PL, Harrison MR, Golbus MS, Adzick NS, Filly RA, Callen PW, et al.: Management of the fetus with congenital hydronephrosis II: prognostic criteria and selection for treatment. J Pediatr Surg, 20: 376-387, 1985.
- Reznik VM, Budorick NE: Prenatal detection of congenital renal disease. Urol Clin North Am, 22: 21-30, 1995.
- Corteville JE, Gray DL, Crane JP: Congenital hydronephrosis: correlation of fetal ultrasonographic findings with infant outcome. Am J Obstet Gynecol, 165: 384-388, 1991.
- Freedman AL, Johnson MP, Gonzalez R: Fetal therapy for obstruction uropathy: past, present... future? Pediatr Nephrol, 14:167-176, 2000.
- Johnson MP, Corsi P, Bradfield W, Hume RF, Smith C, Flake AW, et al.: Sequential urinalysis improves evaluation of fetal renal function in obstructive uropathy. Am J Obstet Gynecol, 173: 59-65, 1995.
- Lewis KM, Pinckert TL, Cain MP, Ghidini A: Complications of intrauterine placement of a vesicoamniotic shunt. Obstet Gynecol, 91: 825-827, 1998.
- Docimo SG, Silver RI: Renal ultrasonography in newborns with prenatally detected hydronephrosis: why wait? J Urol, 157: 1387-1389, 1997.
- Mouriquand PDE, Troisfontaines E, Wilcox DT: Antenatal and perinatal uro-nephrology: current questions and dilemmas. Pediatr Nephrol, 13: 938-944, 1999.
- Reddy PP, Mandell J: Prenatal diagnosis: therapeutic implications. Urol Clin North Am, 25: 171-180, 1998.
- Capolicchio G, Leonard MP, Wong C, Jednak R, Brzezinski A, Salle JLP: Prenatal diagnosis of hydronephrosis: impact on renal function and its recovery after pyeloplasty. J Urol, 162: 1029-1032, 1999.
- Chertin B, Fridmans A, Knizhnik M, Hadas-Halperin I, Hain D, Farkas A: Does early detection of ureteropelvic junction obstruction improve surgical outcome in terms of renal function? J Urol, 162: 1037-1040, 1999.
- Herndon CDA, McKenna PH, Kolon TF, Gonzales ET, Baker LA, Docimo SG: A multicenter outcomes analysis of patients with neonatal reflux presenting with prenatal hydronephrosis. J Urol, 162: 1203-1208, 1999.
- Kokoua A, Homsy Y, Lavigne JF, Williot P, Corcos J, Laberge I, et al.: Maturation of the external urinary sphincter: a comparative histotopographic study in humans. J Urol, 150: 617-622, 1993.
- Vates TS, Shull MJ, Underberg-Davis SJ, Fleisher MH: Complications of voiding cystourethrography in the evaluation of infants with prenatally detected hydronephrosis. J Urol, 162: 1221-1223, 1999.
- Rittenberg MH, Hulbert WC, Snyder HM, Duckett JW: Protective factors in posterior urethral valves. J Urol, 140: 993-996, 1988.
- El-Ghoneimi A, Desgrippes A, Luton D.: Outcome of posterior urethral valves: to what extent is it improved by prenatal diagnosis? J Urol, 162: 849-853, 1999.
- Close CE, Carr MC, Burns MW, Mitchell ME: Lower urinary tract changes after early valve ablation in neonates and infants: is early diversion warranted? J Urol, 157: 984-988, 1997.
- Sbragia-Neto L, Bittencourt DG, Miranda ML, Oliveira-Filho AG, Barini R, Marba S, et al.: Válvula de uretra posterior: Evolução de 10 pacientes com diagnóstico pré-natal. Urodinâmica, 2: 141-148, 1999.
- Walsh DS, Johnson MP: Fetal interventions for obstructive uropathy. Semin Perinatol, 23: 484-495, 1999.
________________________
Received: February 13, 2001
Accepted after revision: March 18, 2002
_______________________
Correspondence address:
Dr. Márcio Lopes Miranda
Unicam, Disciplina de Cirurgia Pediátrica
Cidade Universitária Zeferino Vaz
Distrito Barão Geraldo
Campinas, SP, 13083-970, Brazil
Fax: + + (55) (19) 3788-9347
E-mail: marciomiranda@terra.com.br