WHAT IS KERNICTERUS AND WHAT IS THE CLASSIC TETRAD OF KERNICTERUS?
Chronic bilirubin encephalopathy, irreversible
Choreoathetoid cerebral palsy
High frequency central hearing loss
Palsy of vertical gaze
Dental enamel hypoplasia
WHAT ARE SIGNS OF ACUTE BILIRUBIN ENCEPHALOPATHY?
Alteration in tone of extensor muscles(hypo or hypertonia)
Retrocollis (arching of neck)
Opisthotonus (arching of back)
Cessation of feeding
HOW IS BILIRUBIN PRODUCED AND EXCRETED BY THE NEONATE?
Produced by the breakdown of hemoglobin (hemoglobin is degraded by heme oxygenase releasing iron, CO and biliverdin; biliverdin converted o bilirubin by biliverdin reductase)
Unconjugated bilirubin bound by albumin in blood stream
Unconjugated bili taken up by liver and conjugated by UDPGT (uridine diphophate glucuronosyltransferase)
Conjugated bili excreted into biliary system and intestine
Intestinal bili excreted as stool or becomes unconjugated and reenters bloodstream as unconjugated bili through enterohepatic circulation
WHAT ARE THE MAIN CAUSES OF HYPERBILIRUBINEMIA IN THE NEONATE?
Decreased hepatic uptake of unconjugated bili from circulation
Delayed maturation or inhibition of conjugating mechanism in liver
Increased enterohepatic circulation of unconjugated bili
WHAT TYPE OF BILI PUTS A NEONATE AT RISK FOR ACUTE ENCEPHALOPATHY AND WHY?
Unconjugated only as is lipid soluble and passes the blood brain barrier, conjugated is water soluble and cannot pass the BBB
WHAT ARE RISK FACTORS FOR SEVERE HYPERBILIRUBINEMIA?
Jaundice in the 1st 24 hr of life
Visible jaundice before hosp d/c
Fetal-maternal blood type incompatibility
Significant weight loss
Maternal age > 25
Excessive birth trauma
LGA (in late preterms)
G6PD and breast feeding (in late peterms)
WHAT IS PHYSIOLOGIC JAUNDICE?
Transient elevation in bili that self resolves in 7-10 days
Peaks at day 3-5
WHAT ARE SIGNS OF PATHOLOGIC JAUNDICE?
Onset in 1st 24 hr
Rapidly rising bili level
Prolonged jaundice (> 3 weeks)
Conjugated bili > 20% of total bili
Unwell appearing neonate
WHAT IS YOUR DDX FOR CONJUGATED (DIRECT) HYPERBILI OF THE NEONATE?
Alagille syndrome (ateriohepatic dysplasia)
Inborn errors of metabolism
WHAT IS YOUR DDX OF UNCONJUGATED (INDIRECT) HYPERBILI OF THE NEONATE?
Breast milk jaundice
Physiologic breakdown of birth trauma hematomas
Pyruvte kinase deficiency
Sepsis (esp UTI)
Crigler-Najjar syndrome (absence or deficient UDPGT)
WHY CAN BREASTFEEDING LEAD TO JAUNDICE?
Caloric derivation and dehydration from delayed milk production (takes 2-5 days before maternal milk production up to normal) leading to increased enterohepatic circulation
Inhibition of hepatic B-UGT
WHAT PRESENTATIONS OF NEONATAL JAUNDICE REQUIRE A WORKUP?
Onset in the 1st 24 hr of life
Unwell appearing neonate (lethargy, irritability, poor feeding, temperature instability, vomiting)
> 20% TSB is conjugated
Onset after 7-10 d of life
Persists after 3 weeks (exclude exclusively breast fed neonates without any of above and who appear well)
WHAT ARE 3 TREATMENT MODALITIES USED TO TREAT POTENTIALLY HARMFUL LEVELS OF HYPERBILIRUBINEMIA IN THE NEONATE?
Decreases bili level 15-25%
Blue light converts unconjugated bili to a water soluble compound that is excreted in urine and stool
Used with fetal maternal ABO or Rh incompatibility
Decreases bili level by ~ 50%
Indicated if: signs of intermediate to severe acute bilirubin encephalopathy, level as per AAP guidelines, rising level despite phototherapy