TY - CHAP M1 - Book, Section TI - Hyperbilirubinemia: Conjugated, On Call A1 - Gomella, Tricia Lacy A1 - Eyal, Fabien G. A1 - Bany-Mohammed, Fayez Y1 - 2020 N1 - T2 - Gomella's Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, 8e AB - An infant’s direct (conjugated) serum bilirubin level is elevated at 3 mg/dL. Conjugated bilirubin is the fraction of bilirubin that is conjugated with glucuronic acid in the liver to form bilirubin diglucuronide. It is a biochemical marker of cholestasis. Neonatal cholestasis is conjugated hyperbilirubinemia in the newborn period and is an accumulation of bile substances in the liver. It is secondary to decreased bile secretion from the liver to the duodenum and usually signifies an underlying hepatobiliary or metabolic dysfunction. Cholestasis can be extrahepatic/obstructive (most commonly biliary atresia, other causes include choledochal/biliary cyst, inspissated bile syndrome, obstructive tumors, gallstones) or intrahepatic/nonobstructive (idiopathic, infectious, metabolic/genetic, autoimmune, or toxic). This chapter incorporates recommendations from the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN), the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN), and the American Academy of Pediatrics (AAP) on the management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. NASPGHANdefines an abnormal direct bilirubin as >1 mg/dL. The AAPdefines an abnormal direct bilirubin as >1 mg/dL if the total serum bilirubin (TSB) level is ≤5 mg/dL. If the TSB level is >5 mg/dL, a direct bilirubin >20% of the TSB is abnormal. The majority of prolonged physiologic jaundice is secondary to breast milk jaundice, but it is important not to misdiagnose cholestasis as physiologic jaundice because this will delay the early diagnosis that is essential for treatment. Conjugated hyperbilirubinemia is never normal or physiologic and indicates hepatobiliary dysfunction. It occurs in 1 in every 2500 term infants, and common causes in the newborn infant are biliary atresia (25%–40%), monogenic disorders (25%), and multifactorial or unknown etiologies. The more common causes in premature infants are prolonged parenteral nutrition and sepsis. Timely diagnosis is critical for successful treatment and optimal prognosis, in particular for biliary atresia. Kasai hepatic portoenterostomy should be done as soon as possible to establish bile flow and is best performed within the first 60 days of life (approximately 70% with bile flow vs 90 days). See also Chapter 98 for additional discussion on conjugated hyperbilirubinemia management. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/10/09 UR - accesspediatrics.mhmedical.com/content.aspx?aid=1168356796 ER -