infantile polycystic kidney disease

diagnosis

this diagnosis should be considered when there is enlargement of the kidneys bilaterally without identifiable cysts, no identifiable obstruction, and decreased fluid or oligohydramnios. the condition may be seen as early as 48-50 days gestation, but is usually diagnosed after 16 weeks. prior to 16 weeks there may be some production of amniotic fluid and the specific diagnosis may be more difficult. the kidney to abdomen ratio is greater than 0.27 to 0.30. a midtrimester diagnosis usually includes oligohydramnios and subsequent pulmonary hypoplasia, which makes it a lethal condition. if identified later in pregnancy, the kidneys may become large enough to result in loss of abdominal muscle tone. also, cysts may become large enough to identify individually. over the course of a continuing pregnancy, the kidneys will continue to enlarge and some signs of liver disease (i.e., enlarged bile ducts) may be seen. oligohydramnios will lead to the symptoms of potter’s syndrome (unusual facies, contractures, loose skin). obstetric management should include serial ultrasound evaluations; if there is significant increase in abdominal girth, one must consider the best route for delivery. there is a high risk for stillbirth and pulmonary hypoplasia. ipkd is lethal during the neonatal period in about 80%. since there can be intra-family variability in expression, siblings should be evaluated for mild symptoms like renal insufficiency or childhood hepatic fibrosis. any family history of these problems in siblings can help make the diagnosis prenatally. it also means that a family history of ipkd in a previous pregnancy will not always lead to the identification of the same severe findings in a subsequent affected pregnancy.