Hyperbilirubinemia in the Newborn Flashcards
“Bilirubin encephalopathy” vs “Kernicterus”
Bilirubin encephalopathy: The acute manifestations of bilirubin toxicity
Kernicterus: The chronic and premanent sequellae of bilirubin toxicity
Breastfeeding and hyperbilirubinemia
Breastfeeding every 2-3 hours, particularly in the first several days of life, provide the infant with sufficient energy to begin metabolizing bilirubin
If a mother has not had prenatal blood grouping or is Rh-negative, ___ is recommended
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
Jaundice in an infant is usually best seen. . .
. . . in the face
All measurements of serum bilirubin in infants must be interpreted in relationship to. . .
. . . the infant’s age in hours
Infants with elevated direct bilirubin should receive. . .
. . . urinalysis with culture
Etiology for neonatal jaundice should be sought when. . .
. . . it requires phototherapy or bilirubin is rising rapidly
If response of a jaundiced infant to phototherapy is poor, ___ should be considered
If response of a jaundiced infant to phototherapy is poor, G6PD deficiency should be considered
Workup for jaundice present at or beyond age 3 wk
- 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
Important risk factors for severe neonatal hyperbilirubinemia
- Breastfeeding
- Late-premature gestation (35-38 weeks)
- Significant jaundice present in a sibling
- Jaundice noticed before discharge
Notable causes of neonatal jaundice
- Hemolysis (blood group mismatch, G6PD deficiency, etc)
- Galactosemia
- Criggler-Najjar syndrome
- Hypothyroidism
Bilirubin levels should become about level by neonatal day ___ and return to reference range by neonatal day ___.
Bilirubin levels should become about level by neonatal day 5 and return to reference range by neonatal day 14.
First-line therapy for neonatal hyperbilirubinemia
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.
If hyperbilirubinemia in an infant with isoimmune hemolytic disease fails to respond to phototherapy, ___ is the next step prior to progressing to exchange transfusion
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
Second-line therapy for neonatal severe hyperbilirubinemia
Exchange transfusion
This is recommended under the following circumstances:
- If phototherapy fails
- If bilirubin > 25 mg/dL
- If there are signs or symptoms of bilirubin encephalopathy
The threshold for initiating phototherapy should be lower in infants with a low serum ___.
The threshold for initiating phototherapy should be lower in infants with a low serum albumin (< 3.0 g/dL)
Signs and symptoms of bilirubin encephalopathy in the newborn
- Hypertonia
- Arching back/opisthotonus (think tetanus)
- Retrocollis (neck stuck in an extended position, as in torticollis)
- Fever
- High-pitched cry
Best test for assessing the severity of hemolysis in the newborn
End-tidal carbon monoxide
Can confirm the presence or absence of hemolysis
Tin-mesoporphyrin
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.
Physiologic jaundice
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.
Breast milk jaundice
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.
Most common cause of nonphysiologic unconjugated hyperbilirubinemia
ABO hemolytic anemia
Frequent causes of nonphysiologic conjugated hyperbilirubinemia
- Biliary atresia
- Neonatal hepatitis
- Congenital infection
- Alpha-1 antitrypsin deficiency
- Galactosemia
- Fructosemia
Kernicterus only occurs in. . .
. . . unconjugated hyperbilirubinemia
Which makes sense. Conjugated bilirubin is soluble, it will not deposit anywhere.
Often __ is the first ‘treatment’ a jaundiced infant will receive
Often hydration is the first ‘treatment’ a jaundiced infant will receive
If the infant is dehydrated, restoring fluid will dilute the bilirubin.
Main indications for exchange transfuson in hyperbilirubinemia
- Bilirubin > 25 mg/dL
- Signs and symptoms of bilirubin encephalopathy
Things that may increase bilirubin production in a given newborn
- Cephalhematoma
- Bruising
- Hemolysis (ABO, RhD)
- RBC defect (G6PD, PKD, HgbSS, spherocytosis, etc)
- Polycythemia of any etiology
Breastfeeding jaundice
Insufficient supply/feeding -> fewer stools -> poor excretion of bilirubin
Approach to newborn jaundice
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Workflow diagram for neonatal jaundice
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Generally, breastfeeding and breast milk jaundice are very similar in presentation. So, they are often treated the same way: . . .
. . . feed them more and feed them hydrolyzed formula instead of normal breast milk
This addresses both possibilities.