Antenatally detected urinary tract dilatation: long-term outcome

Abstract

This review provides updated knowledge on the long-term outcomes among children with antenatally diagnosed urinary tract dilatation (UTD), previously often referred to as antenatal hydronephrosis. Different definitions of UTD exist, which makes comparison between studies and generalized conclusions difficult. Roughly, one-third of antenatally diagnosed UTD, defined as a renal pelvis anterior posterior diameter (APD) of ≥ 4 mm in the second trimester and/or ≥ 7 mm in the third trimester, will resolve before birth, another third will resolve within the first years of life, and in the remaining cases, UTD will persist or a congenital abnormality (CAKUT) will be diagnosed postnatally. The risk of a postnatal CAKUT diagnosis increases with the degree of prenatal and postnatal dilatation, except for vesicoureteral reflux (VUR), which cannot be predicted from the degree of UTD. Urinary tract infections (UTIs) occur in 7–14% of children with UTD during the first years of life. The risk of UTI is higher in children with traditional risk factors for UTI, such as dilated VUR, hydroureteronephrosis, female gender, and intact foreskin. Continuous antibiotic prophylaxis may be considered in selected patients during the first years of life. In long-term follow-ups, permanent kidney damage is diagnosed in approximately 40% of children with moderate or severe UTD, but hypertension, proteinuria, and/or reduced eGFR are uncommon (0–5%). In children with mild UTD, the long-term outcome is excellent, and these children should not be subjected to unnecessary examinations and/or follow-up.

Scinтigraphy in Children with Urinary Tract Dilatation (Antenatally Detected Hydronephrosis)

“…Roughly, one-third of antenatally diagnosed UTD, defi ned as an APD of ≥ 4 mm in the second trimester and/or ≥ 7 mm in the third trimester, will resolve before birth, another third will resolve within the fi rst years of life, and in the remaining cases, UTD will persist or a Congenital Abnormality of Kidney and Urinary Tract (CAKUT) will be diagnosed postnatally [1].…”

“…Antenatal Hydronephrosis (ANH) is one of the most common fetal anomalies detected in pregnancy. Previously, this condition was referred to as congenital, antenatal, or prenatal hydronephrosis, but urinary tract dilatation UTD is now the preferred term [1]. The introduction of routine fetal Ultrasound (US) screening in the 1990s has resulted in increasing recognition of Antenatal Hydronephrosis (ANH) [2].…”