commentary

The challenges of diagnosing obstructive hydronephrosis in children

Kourosh Afshar, MD, MHSc, FRCSC

Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada

Cite as: Can Urol Assoc J 2016;10(3-4):101. http://dx.doi.org/10.5489/cuaj.3739

shown a reduction in numbers of pyeloplasties based on

the degree of gravity-assisted drainage (GAD), they have

not presented the evidence to support the usefulness of their

approach. For example, the followup length and the ultimate

outcome of renal units that had prolonged drainage, but did

not have pyeloplasty based on GAD, are unknown.

See related article on page 96.

he paper by Acker et al illustrates the challenges pedi-

atric urologists face in diagnosing obstructive hydro-

This study again demonstrates the pitfalls of labeling a

dilated system as obstructed based only on drainage param-

eters, which in turn, may result in unnecessary surgery.

nephrosis. The problem begins with the lack of accu-

rate “gold standard” test to identify obstruction. Historically

drainage parameters (such as T max) from a diuretic renal

nuclear scan have been used to guide the diagnosis. The

diagnostic value of these parameters has been challenged

by multiple studies: “a dilated system may take longer to

Competing interests: The author declares no competing ﬁnancial or personal interests.

drain with no obstruction.”

References

The current study evaluates the usefulness of an auxiliary

method to enhance the discriminative value of diuretic renal

scans. The authors assessed the changes in the drainage after

facilitating the urinary ﬂow from the kidney by gravity. The

hypothesis is that this maneuver improves the accuracy of

the test by increasing true and reducing false positives, but

one only can deﬁne true and false positive when a reference

test is available. Since there is no gold standard, urologists

have used conﬁrmative evidence to circumvent this deﬁ-

ciency. Examples include clinical complications, such as

pain, progressive hydronephrosis, and reduction in renal

function. In the current study, although the authors have

Acker MR, Clark R, Anderson P. Gravity-assisted drainage imaging in the assessment of pediatric hydrone-

phrosis. Can Urol Assoc J 2016;10(3-4):96-100. http://dx.doi.org/10.5489/cuaj.3237

Amarante J, Anderson PJ, Gordon I. Impaired drainage on diuretic renography using half-time or pelvic

excretion efﬁciency is not a sign of obstruction in children with a prenatal diagnosis of unilateral renal pelvic

dilatation. J Urol 2003;169:1828-31. http://dx.doi.org/10.1097/01.ju.0000062640.46274.21

3. Koff SA, Binkovitz L, Coley B, et al. Renal pelvis volume during diuresis in children with hydronephrosis:

Implications for diagnosing obstruction with diuretic renography. J Urol 2005;174:303-7. http://dx.doi.

org/10.1097/01.ju.0000161217.47446.0b

Correspondence: Dr. Kourosh Afshar, Department of Urologic Sciences, University of British Columbia,

Vancouver, BC, Canada; kafshar@cw.bc.ca

CUAJ • March-April 2016 • Volume 10, Issues 3-4

2016 Canadian Urological Association

101