Autosomal Recessive Polycystic Kidney Disease (ARPKD

Fetal ultrasound for Auto somal Recessive Polycystic Kidney Disease (ARPKD) typically reveals symmetrically enlarged, highly echogenic (bright) kidneys, often detectable by the second trimester (around 18-24 weeks). The kidneys frequently show a “salt-and-pepper” or heterogeneous texture due to tiny cysts, leading to significantly reduced amniotic fluid (oligohydramnios).  Ultrasound Findings (ARPKD):Renomegaly: Significantly enlarged kidneys (nephromegaly) that may fill the abdomen.Echogenicity: Hyperechoic (bright) kidney parenchyma, often without clear separation between the cortex and medulla.Cysts: While the disease is cystic, the cysts are often microscopic or too small to resolve (typically $$ cm), differentiating it from the larger cysts in Autosomal Dominant PKD (ADPKD).Oligohydramnios: Decreased amniotic fluid, which is a significant indicator, often leading to pulmonary hypoplasia.Reversed corticomedullary differentiation: The medulla may appear brighter than the cortex. Timing and Progression:Early Detection: While sometimes seen earlier, characteristic findings are usually prominent in the second half of pregnancy.Serial Scans: Serial ultrasounds are used to monitor kidney enlargement and amniotic fluid appearance of ARPKD can overlap with other conditions. Similar findings include: Autosomal Dominant Polycystic Kidney Disease (ADPKD).Meckel-Gruber syndrome.Congenital nephrotic syndrome