Hyperbilirubinemia in the Newborn

Question 1

“Bilirubin encephalopathy” vs “Kernicterus”

Answer 1

Bilirubin encephalopathy: The acute manifestations of bilirubin toxicity

Kernicterus: The chronic and premanent sequellae of bilirubin toxicity

Question 2

Breastfeeding and hyperbilirubinemia

Answer 2

Breastfeeding every 2-3 hours, particularly in the first several days of life, provide the infant with sufficient energy to begin metabolizing bilirubin

Question 3

If a mother has not had prenatal blood grouping or is Rh-negative, ___ is recommended

Answer 3

If a mother has not had prenatal blood grouping or is Rh-negative, Coomb’s test, blood type, and RhD type on cord blood is recommended

Question 4

Jaundice in an infant is usually best seen. . .

Answer 4

. . . in the face

Question 5

All measurements of serum bilirubin in infants must be interpreted in relationship to. . .

Answer 5

. . . the infant’s age in hours

Question 6

Infants with elevated direct bilirubin should receive. . .

Answer 6

. . . urinalysis with culture

Question 7

Etiology for neonatal jaundice should be sought when. . .

Answer 7

. . . it requires phototherapy or bilirubin is rising rapidly

Question 8

If response of a jaundiced infant to phototherapy is poor, ___ should be considered

Answer 8

If response of a jaundiced infant to phototherapy is poor, G6PD deficiency should be considered

Question 9

Workup for jaundice present at or beyond age 3 wk

Answer 9

• Total and direct bilirubin
  
  • If direct elevated, check for signs of cholestasis
• Check results of neonatal thyroid and galactosemia screening, evaluate infant for signs of hypothyroidism

Question 10

Important risk factors for severe neonatal hyperbilirubinemia

Answer 10

• Breastfeeding
• Late-premature gestation (35-38 weeks)
• Significant jaundice present in a sibling
• Jaundice noticed before discharge

Question 11

Notable causes of neonatal jaundice

Answer 11

• Hemolysis (blood group mismatch, G6PD deficiency, etc)
• Galactosemia
• Criggler-Najjar syndrome
• Hypothyroidism

Question 12

Bilirubin levels should become about level by neonatal day ___ and return to reference range by neonatal day ___.

Answer 12

Bilirubin levels should become about level by neonatal day 5 and return to reference range by neonatal day 14.

Question 13

First-line therapy for neonatal hyperbilirubinemia

Answer 13

Phototherapy

The light helps photoconvert unconjugated bilirubin into a more soluble product. This also then opens up more space on albumin to bind up the unbound native bilirubin fraction.

Side effects include frequent and loose bowel movements (part of the process of removing bilirubin, on-target effect)

Caveat: If the hyperbilirubinemia is predominately conjugated, this therapy obviously will not help.

Question 14

If hyperbilirubinemia in an infant with isoimmune hemolytic disease fails to respond to phototherapy, ___ is the next step prior to progressing to exchange transfusion

Answer 14

If hyperbilirubinemia in an infant with isoimmune hemolytic disease fails to respond to phototherapy, IVIG is the next step prior to progressing to exchange transfusion

Question 15

Second-line therapy for neonatal severe hyperbilirubinemia

Answer 15

Exchange transfusion

This is recommended under the following circumstances:

1. If phototherapy fails
2. If bilirubin > 25 mg/dL
3. If there are signs or symptoms of bilirubin encephalopathy

Question 16

The threshold for initiating phototherapy should be lower in infants with a low serum ___.

Answer 16

The threshold for initiating phototherapy should be lower in infants with a low serum albumin (< 3.0 g/dL)

Question 17

Signs and symptoms of bilirubin encephalopathy in the newborn

Answer 17

• Hypertonia
• Arching back/opisthotonus (think tetanus)
• Retrocollis (neck stuck in an extended position, as in torticollis)
• Fever
• High-pitched cry

Question 18

Best test for assessing the severity of hemolysis in the newborn

Answer 18

End-tidal carbon monoxide

Can confirm the presence or absence of hemolysis

Question 19

Tin-mesoporphyrin

Answer 19

Pharmacologic agent which has been shown to prevent and treat pathologic hyperbilirubinemia in the newborn

Not currently approved in the US, but will probably come soon. Would likely replace exchange transfusion as the second-line agent, with phototherapy retaining the first-line position.

Question 20

Physiologic jaundice

Answer 20

Indirect hyperbilirubinemia which occurs in the neonate in the absence of underlying abnormalities in bilirubin metabolism.

Will not be present before 24 hours and peaks at day 3-5 at <15 mg/dL. Should normalize by day 14-21.

Infants born preterm have later and higher peak bilirubin.

Question 21

Breast milk jaundice

Answer 21

Jaundice associated with breastfeeding. Typically occurs ~1 week after birth and may last for a few months.

Theory is that beta glucuronidase in breastmilk unconjugates bilirubin.

Disruption of breastfeeding is NOT recommended, despite jaundice. Jaundice can be treated with phototherapy while the baby continues to breastfeed.

Question 22

Most common cause of nonphysiologic unconjugated hyperbilirubinemia

Answer 22

ABO hemolytic anemia

Question 23

Frequent causes of nonphysiologic conjugated hyperbilirubinemia

Answer 23

• Biliary atresia
• Neonatal hepatitis
• Congenital infection
• Alpha-1 antitrypsin deficiency
• Galactosemia
• Fructosemia

Question 24

Kernicterus only occurs in. . .

Answer 24

. . . unconjugated hyperbilirubinemia

Which makes sense. Conjugated bilirubin is soluble, it will not deposit anywhere.

Question 25

Often __ is the first ‘treatment’ a jaundiced infant will receive

Answer 25

Often hydration is the first ‘treatment’ a jaundiced infant will receive

If the infant is dehydrated, restoring fluid will dilute the bilirubin.

Question 26

Main indications for exchange transfuson in hyperbilirubinemia

Answer 26

1. Bilirubin > 25 mg/dL
2. Signs and symptoms of bilirubin encephalopathy

Question 27

Things that may increase bilirubin production in a given newborn

Answer 27

• Cephalhematoma
• Bruising
• Hemolysis (ABO, RhD)
• RBC defect (G6PD, PKD, HgbSS, spherocytosis, etc)
• Polycythemia of any etiology

Question 28

Breastfeeding jaundice

Answer 28

Insufficient supply/feeding -> fewer stools -> poor excretion of bilirubin

Question 29

Approach to newborn jaundice

Answer 29

Question 30

Workflow diagram for neonatal jaundice

Answer 30

Question 31

Generally, breastfeeding and breast milk jaundice are very similar in presentation. So, they are often treated the same way: . . .

Answer 31

. . . feed them more and feed them hydrolyzed formula instead of normal breast milk

This addresses both possibilities.