Pediatrics - Neonatal Jaundice

Pediatrics

[NEONATAL JAUNDICE]

Introduction Jaundice in a neonate usually doesn’t indicate something as ominous (like pancreatic cancer) as it does in an adult. However, the jaundice itself can be hazardous. Just like an adult, there are prehepatic (hemolysis), intrahepatic (metabolic), and posthepatic (biliary obstruction) causes. In a neonate (especially in a preemie) hepatic function is far less than an adult, compounding any problems. Types of Bilirubin There are two types of bilirubin. Conjugated bilirubin is water soluble so it can’t cross blood brain barrier but can be excreted in the urine. It can’t cause brain damage but is always pathologic - indicative of problems with biliary excretion . Conversely, unconjugated  bilirubin is lipid-soluble so it can cross blood brain barrier, potentially leading to kernicterus  (irreversible deposition in the basal ganglia and pons). It’s potentially fatal . Unconjugated bilirubin is either prehepatic (hemolysis) or intrahepatic in adults, but can actually be physiologic in a neonate. Workup for Jaundice The most important thing to do is draw a bilirubin level . Indirect hyperbilirubinemia requires immediate therapy to prevent kernicterus (usually occurring with a bili > 20). The goal should  be to decide decide where the bilirubin is coming from using using a Coomb’s Test (isoimmunization), CBC, and a Reticulocyte count  (pay  particular attention to the tree to the right). All of these can overwhelm the liver with “too much bilirubin.” On the contrary, a direct hyperbilirubinemia is more dangerous. It requires a workup for sepsis (WBC, Blood Cx), obstruction (HIDA scan), and almost any metabolic disease (Crigler-Najjar, Rotor’s, Dubin-Johnson). Treatment of Jaundice Keep an eye on the bilirubin. If levels get >20 then the risk of kernicterus is too great and an exchange perfusion must be  performed. For mild elevations elevations (>10) the baby goes under a Blue lamp (or gets put near a window). The UV changes the indirect to direct bili (excreted in the urine). However, do not Blue a direct  bili because it it won’t help and and it’ll just end up bronzing the baby. The goal of indirect therapy is to make it water-soluble. Direct  bilirubin already is.

Prehepatic Too much Blood Too much Hemolysis Intrahepatic Crigler-Najjar Dubin-Johnson Post-hepatic Gilbert’s Atresia Rotor’s Sepsis Hepatitis Obstruction Sepsis

UNCONJUGATED Lipid Soluble Cross BBB Kernicterus Ø Urine Excretion

Water Soluble Can’t Cross BBB Ø Kernicterus Urinary Excretion

PHYSIOLOGIC Onset > 72 hrs  Bilirubin ↑ 1 week  (term)  (term) > 2 weeks (preterm) Baby is Yellow

Unconjugated

Conjugated Bilirubin Direct

Indirect

Coombs Coomb’s Test

Isoimmunization

Coombs Hgb

HIDA Scan , U/S Sepsis Metabolic

Rh Disease ABO Incapability Blood Transfusion  High  Hgb

 Normal  Hgb Retic Count

Breast Feeding vs Breast Milk Jaundice In Breast Feeding, Jaundice is a quantity issue. Without sufficient volume bowels don’t move fast enough; the body reabsorbs bilirubin  and bilirubin builds up. By increasing the number of feeds the problem fixes itself. In order to be reabsorbed from the gut the bilirubin must be unconjugated so there will be an elevation in indirect bilirubinemia.

CONJUGATED

Hemorrhage

Twin-Twin Transfusion Maternal-Baby Delayed Cord Clamping Hemolysis Spherocytosis G6PD Disease Pyruvate Kinase Def

Hemorrhage Breast Milk Jaundice Reabsorption

B reast reast Mi lk

B reast reast F eedi ng

10 days out of birth = Physiologic Enzyme Inhibition Not enough Insufficient Conjugation ↑ Enterohepatic Reabsorption Supplement ↑ Feed Frequency

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