Management of antenatally detected kidney malformations

Congenital anomalies of the kidneys and the urinary tract (CAKUT) are one of the most common sonographically identified antenatal malformations. Dilatation of the renal pelvis accounts for the majority of cases, but this is usually mild rather than an indicator of obstructive uropathy. Other conditions such as small through large hyperechogenic and/or cystic kidneys present a significant diagnostic dilemma on routine scanning. Accurate diagnosis and prediction of prognosis is often not possible without a positive family history, although maintenance of adequate amniotic fluid is usually a good sign. Both pre- and postnatal genetic screening is possible for multiple known CAKUT genes but less than a fifth of non-syndromic sporadic cases have detectable monogenic mutations with current technology. In utero management options are limited, with little evidence of benefit from shunting of obstructed systems or installation of artificial amniotic fluid. Often outcome hinges on associated cardiac, neurological or other abnormalities, particularly in syndromic cases. Hence, management centres on a careful assessment of all anomalies and planning for postnatal care. Early delivery is rarely indicated since this exposes the baby to the risks of prematurity in addition to their underlying CAKUT. Parents value discussions with a multidisciplinary team including fetal medicine and paediatric nephrology or urology, with neonatologists to plan perinatal care and clinical geneticists for future risks of CAKUT.