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19–22 APRIL, 2017, BARCELONA, SPAIN
S18: PRENATAL UROLOGY
Moderators: Anthony Herndon (USA), Claudio di Carli (Argentina)
ESPU Meeting on Friday 21, April 2017, 16:00–16:24
16:00–16:03
S18-1 (PP)
★
CONGENITAL SOLITARY FUNCTIONING KIDNEY,
HYPERTROPHY OR HYPERPLASIA? – A FETAL
ULTRASOUND STUDY
R. SNOEK
1
, R. DE HEUS
1
, K.L. DE MOOIJ
2
, L.R. PISTORIUS
3
, M.N. BEKKER
1
and T.P.V.M. DE JONG
4
1) University Utrecht Medical Center, Obstetrics, Utrecht, NETHERLANDS - 2) University Utrecht Medical Center,
Pediatric Urology, Utrecht, NETHERLANDS - 3) Tygerberg Hospital and Stellenbosch University, Obstetrics, Cape Town
And Stellenbosch, SOUTH AFRICA - 4) University Utrecht Medical Center and Academic Medical Center, Pediatric
Urology, Utrecht And Amsterdam, NETHERLANDS
PURPOSE
Congenital solitary functioning kidney (CSFK) occurs in unilateral renal agenesis and multicystic
dysplastic kidney. The ‘hyperfiltration hypothesis’ states that the theoretical 50% loss of nephrons
leads to hyperfiltration, with subsequent nephron hypertrophy and risk of renal injury. However,
animal studies report signs of hyperplasia (increase in actual number of functioning nephrons) and
an increase in the number of renal papillae. We aim to assess renal papilla number (RPN) with fetal
ultrasound (US) to assess the role of hyperplasia in CSFK.
PATIENTS AND METHODS
A case-control study was performed on conventional and three dimensional fetal US images of
fetuses with CSFK and healthy control fetuses. ‘Renal papilla’ was defined as a hyperechogenic
focus near the renal pelvis. All imaging was assessed twice by two independent observers.
RESULTS
Sixty CSFK fetuses and 60 controls were included. Mean RPN is higher (p<0.001) in CSFK
(8.00±1.14) than in controls (6.05±1.23). RPN increases (p>0.001-0.001) with 0.11 and 0.09 papil-
lae per gestational week in cases and controls respectively. This does not differ between groups
(p=0.48). Conventional and three dimensional US are comparable (p=0.39) and moderately reliable
in assessing RPN, with 0.90 (95% CI 0.85-0.94) and 0.68 (95% CI 0.44-0.81) interclass correlation
coefficients in intra- and inter-observer measurements respectively.
CONCLUSIONS
We pose that the higher RPN in CSFK supports our hypothesis of nephron hyperplasia and not
(only) hyperfiltration resulting in hypertrophy, challenging the hyperfiltration hypothesis. RPN might
serve as a predictor for risk of developing renal injury, as a higher nephron number would result
in lower risks of renal injury.