139Developmental Period Medicine, 2016;XX,2© IMiD, Wydawnictwo Aluna

Grażyna Krzemień1, Agnieszka Szmigielska1, Przemysław Bombiński2, Marzena Barczuk2, Agnieszka Biejat2, Stanisław Warchoł3, Teresa Dudek-Warchoł3

EXTREME HYDRONEPHROSIS DUE TO URETROPELVIC JUNCTION OBSTRUCTION IN INFANT �CASE REPORT�

SKRAJNE WODONERCZE W WYNIKU ZWĘŻENIA PODMIEDNICZKOWEGO MOCZOWODU U NIEMOWLĘCIA

�OPIS PRZYPADKU�

1Department of Pediatric Nephrology, !e Medical University of Warsaw, Poland2Department of Pediatric Radiology, !e Medical University of Warsaw, Poland

3Department of Pediatric Surgery and Urology, !e Medical University of Warsaw, Poland

AbstractBackground: Hydronephrosis is the one of the most common congenital abnormalities of urinary tract.

The left kidney is more commonly a�ected than the right side and is more common in males.

Aim of the study: To determine the role of ultrasonography, renal dynamic scintigraphy and lower-

dose computed tomography urography in preoperative diagnostic workup of infant with extreme

hydronephrosis.

Case report: We presented the boy with antenatally diagnosed hydronephrosis. In serial, postnatal

ultrasonography, renal scintigraphy and computed tomography urography we observed slightly

declining function in the dilated kidney and increasing pelvic dilatation. Pyeloplasty was performed at

the age of four months with good result.

Conclusions: Results of ultrasonography and renal dynamic scintigraphy in child with extreme

hydronephrosis can be di!cult to asses, therefore before the surgical procedure a lower-dose computed

tomography urography should be performed.

Key words: hydronephrosis, UPJO, renal dynamic scintigraphy, lower-dose computed tomography

urography, pyeloplasty

StreszczenieWstęp: Wodonercze należy do najczęściej rozpoznawanych wad układu moczowego, zwykle dotyczy

nerki lewej, częściej występuje u chłopców.

Cel pracy: Ocena przydatności badania ultrasonogra&cznego, scyntygra&i dynamicznej nerek i urogra&i-

tomogra&i komputerowej z obniżoną dawką promieniowania w przedoperacyjnej diagnostyce skrajnego

wodonercza u niemowlęcia.

Opis przypadku: Przedstawiamy przypadek chłopca z bezobjawowym wodonerczem wykrytym

prenatalnie. W powtarzanych badaniach ultrasonogra&cznych i izotopowych oraz w urogra&i-

tomogra&i komputerowej obserwowano narastanie stopnia wodonercza i zablokowany odpływ

moczu z nerki, przy nieznacznie obniżonym udziale nerki w oczyszczaniu. W wieku 4 miesięcy wykonano

plastykę miedniczkowo-moczowodową z dobrym wynikiem.

Wnioski: Wyniki badania ultrasonogra&cznego i scyntygra&i dynamicznej nerek u dziecka ze skrajnym

wodonerczem mogą być trudne do oceny, dlatego przy kwali&kacji do operacji może być konieczne

wykonanie urogra&i tomogra&i komputerowej z obniżoną dawką promieniowania.

Słowa kluczowe: wodonercze wrodzone, zwężenie podmiedniczkowe moczowodu, scyntygra#a

dynamiczna nerek, urogra#a tomogra#i komputerowej z obniżoną dawką promieniowania, plastyka

miedniczkowo-moczowodowa

DEV PERIOD MED. 2016;XX,2:139�142

140 Grażyna Krzemień et al.

BACKGROUND

Congenital anomalies of kidney and urinary tract (CAKUT) occur in 17.7:1000 live births [1]. One of the most common of CAKUT is hydronephrosis. It usually a"ects the le# kidney and is diagnosed in boys [2, 3]. Hydronephrosis can be caused by: ureteropelvic junction obstruction (UPJO), hypoplastic proximal part or high origin of the ureter, additional vessel crossing ureteropelvic junction, and the isthmus of the horseshoe kidney [3, 4, 5]. Ultrasonography (US) and dynamic scintigraphy are the basic imaging modalities in children [6, 7]. CT urography (CTU), MR urography, as well as classic X-ray urography, are less frequently used [2, 4, 8].

CASE REPORT

We present the boy delivered at term in a good clinical condition. Le#-sided hydronephrosis was diagnosed and followed-up in antenatal US examinations. Postnatal US revealed: enlarged le# kidney (65mm in length) with thin parenchyma (up to 2 mm), with dilated calyces (up to 21 mm) and pelvis (22 mm in anterior-posterior diameter − APD) (%g. 1); right kidney (54 mm in length) with slightly dilated calyces (up to 3 mm) and pelvis (7 mm in APD). Voiding cystourethrography was normal. Dynamic scintigraphy with Technetium 99m-L,L-ethylenedicysteine (99mTc-EC) and furosemide revealed high-grade hydronephrosis with decreased excretory function and obstruction at the level of ureteropelvic junction, with thin parenchyma and relative renal function 40,5% for the le# kidney and 59,5% for the right kidney (100% ERPF for both kidneys). In the 3rd month of life a follow-up US was performed, which revealed increase of hydronephrosis – enlargement of the le# kidney (103 mm in length), calyces (up to 24-27 mm) and pelvis (31 mm in APD) was noticed. Because of the suspected caliectasis, lower-dose CTU was performed (%g. 2, %g. 3). It revealed high-grade hydronephrosis with thin,

poorly functioning parenchyma (only small amount of contrast agent appeared in collecting system). Follow-up scintigraphy revealed no improvement of the le# kidney function (%g. 4). In the 4th month of life, Hynes-Anderson pyeloplasty was performed, which con%rmed critical UPJO. A „double-J” 3FR, 12 cm, catheter was le# for 2 months. Follow-up US revealed mild improvement based on the le# kidney image – kidney length decreased to 94 mm, calyces up to 22 mm, pelvis 21 mm in APD. However, in scintigraphy there were present signs of obstruction and there were no improvement in kidney function (similar relative renal function: 40% for the le# kidney and 60% for the right kidney).

DISCUSSION

In the past, urinary tract infection with suspected congenital abnormality was the main indication for diagnostic imaging procedures in children. Nowadays, antenatal ultrasonography is the key imaging modality for early detection of congenital abnormalities [4, 6, 9]. In our patient, it allowed for appropriate management immediately a#er the birth. US in hydronephrosis allows to assess the grade of pelvicalyceal system dilatation, with the most important parameter, which is the APD of the pelvis [10, 11, 12]. Clinically signi%cant UPJO is diagnosed in case of increase of hydronephrosis in follow-up US examinations, as well of thinning of the kidney parenchyma or compensatory enlargement of the contralateral kidney [13]. Pelvic APD greater than 10-15mm is an indication for dynamic scintigraphy [9]. Clinically signi%cant UPJO is recognised in case of impaired or slow radioisotope out'ow, deterioration in kidney function below 40% or obstructive renogram curve [13]. Most widely used criteria for surgical treatment of hydronephrosis in children depend on results of US and dynamic scintigraphy. Increasing hydronephrosis in follow-up US examinations (with pelvic APD >30 mm), and/or deterioration of kidney function in scintigraphy (<40% ERPF) with signs of impaired or slowed out'ow should lead to surgical treatment [4, 9, 14, 15]. !e abnormal, decreased blood 'ow through the kidneys can cause lower uptake of contrast in renal scintigraphy. !e obstructed kidney due to UPJO is also not responsive to furosemide stimulation. At the same time, the collecting system is easy to stretch. In our case, a boy presented increasing hydronephrosis and thinning of the kidney parenchyma in follow-up US examinations, as well as increasing obstruction and deterioration of kidney function (up to 40%) and thinning of the kidney parenchyma (“egg-shell sign”) in scintigraphy. Our patient was quali%ed to surgical intervention, despite high relative renal function (up to 40%). However, usually one can assume that in children with critical hydronephrosis, relative renal function is o#en overestimated. It can be related to longer presence of the radioisotope in dilated pelvicalyceal system and should be taken into consideration during scintigraphy assessment. In practice contrast examinations are rarely indicated in children with hydronephrosis. In our hospital, classic X-ray urography was replaced with lower-dose CTU. Computed tomography urography with iterative

Fig. 1. Postnatal US examina!on revealed high-grade hydro-nephrosis of the le" kidney.

Ryc. 1. Postnatalne badanie ultrasonograficzne wykazało wodonercze lewostronne znacznego stopnia.

141Extreme hydronephrosis due to uretropelvic junction obstruction in infant (case report)

Fig. 3. Lower-dose computed tomography urography revealed le" sided high-grade hydronephrosis. Le" kidney with poorly func!oning parenchyma and only small amount of contrast agent in the lower calyx.

Ryc. 3. Urografia tomografii komputerowej z obniżoną dawką promieniowania wykazała wodonercze lewostronne znacznego stopnia. Warstwa miąższowa nerki lewej słabo wydzielająca środek cieniujący, tylko niewielka ilość środka cieniującego obecna w dolnym kielichu nerki.

Fig. 2. Dynamic scin!graphy with 99mTc-EC revealed le" sided high-grade hydronephrosis with decreased excretory func!on and obstruc!on at the level of ureteropelvic junc!on, with mild dilata!on of the right sided pelvi-calyceal system. Rela!ve renal func!on: 40% for the le" kidney and 60% for the right kidney.

Ryc. 2. Scyntygrafia dynamiczna nerek z użyciem 99mTc-Ec wykazała wodonercze lewostronne znacznego stopnia z obniżonym udziałem nerki w oczyszczaniu i objawami utrudnionego wydalania na poziomie ujścia miedniczkowo-moczowodowego. Niewielkie poszerzenie układu kielichowo-miedniczkowego po stronie prawej. Relatywny udział nerek w oczyszczaniu: nerka lewa 40%, nerka prawa 60%.

Fig. 4. Lower-dose computed tomography urography volume rendered reconstruc!on.

Ryc. 4. Urografia tomografii komputerowej z obniżoną dawką promieniowania, rekonstrukcja objętościowa.

reconstruction techniques (with multiplanar reformatted and volume rendered reconstructions) allows precisely assessment of the urinary tract anatomy. It is performed when there is no correlation between the results of US and dynamic scintigraphy (i.e. when the grade of pelvicalyceal system dilatation in US does not match the grade of obstruction in scintigraphy), and for assessment of the cause of hydronephrosis in non-typical cases (i.e. high origin of the ureter, crossing vessel, suspected caliectasis, or hydronephrosis in the horseshoe kidney) [8]. In our case, lower-dose CTU was performed for general anatomy assessment before surgical intervention, due to suspected caliectasis in US. Voiding cystourethrography was performed for exclusion of vesicoureteral re'ux as a cause of hydronephrosis before surgical intervention. According to the literature, 7,5-23,9% of newborns with asymptomatic hydronephrosis and initial non-operative approach, will require surgical intervention in the future [10, 11, 16, 17]. In some cases, improvement of hydronephrosis may be observed many months a#er the surgical intervention [17]. In our case, ultrasonography performed 3 months a#er surgical treatment revealed decrease of hydronephrosis, however scintigraphy revealed persistent obstruction and no improvement in kidney function.

142 Grażyna Krzemień et al.

CONCLUSIONS

Results of ultrasonography and renal dynamic scintigraphy in child with extreme hydronephrosis can be di*cult to asses, therefore before surgical procedure a computed tomography urography should be performed.

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Author’s contributions/Wkład Autorów

According to the order of the Authorship/Według kolejności

Con"icts of interest/Kon"ikt interesu

!e Authors declare no con'ict of interest.Autorzy pracy nie zgłaszają kon'iktu interesów.

Received/Nadesłano: 24.02.2016 r.Accepted/Zaakceptowano: 25.05.2016 r.

Published online/Dostępne online

Address for correspondence:Grażyna Krzemień

Department of Pediatric Nephrology,!e Medical University of Warsaw

Żwirki i Wigury 63A, 02-091 Warsaw, Polandtel. (+48-22) 628-97-22

fax. (+48-22) 621-41-55e-mail: grazyna.krzemien@litewska.edu.pl