Neonatal Cholestasis: A Primer of Selected Etiologies.

Cholestasis refers to impairment in formation or excretion of bile. This can be due to defects in intrahepatic production of bile, defects in the transmembrane transport of bile, or mechanical obstruction to bile flow. Clinical features of cholestasis reflect the retention of components of bile (bilirubin, bile acids, cholesterol) in the body. In the neonatal period, hyperbilirubinemia can be categorized as either unconjugated (and often benign) hyperbilirubinemia, or conjugated hyperbilirubinemia due to cholestasis. It is for this reason that the first laboratory evaluation in a patient with jaundice, dark urine, and/or acholic stool is a fractionated bilirubin. This article serves as a practical primer for pediatric and neonatology trainees and covers common causes of neonatal cholestasis, as well as the diagnostic work-up and treatment. Causes that are discussed include biliary atresia, idiopathic neonatal hepatitis, gestational alloimmune liver disease, metabolic and genetic diseases, total parenteral nutrition cholestasis, and congenital infection. [Pediatr Ann. 2018;47(11):e433-e439.].