1.5 MTB Step 3 - The Newborn (Jaundice)

Question 1

JAUNDICE IN THE NEWBORN

DIAGNOSIS

Describe the Flowchart for diagnosing Jaundice in the Newborn.

Answer 1

Physiologic (Indirect/Unconjugated):

• Coombs (+)
  
  • Rh/ABO Incompatibility
  • Thalassemia minor
• Coombs (-)
  
  • High Hemoglobin
    
    • Polycythemia
    • Twin-Twin transfusion
    • Maternal-Fetal transfusion
    • Delayed Cord
    • IUGR
    • IODM
  • Normal/Low Hemoglobin
    
    • Spherocytosis
    • Elliptocytosis
    • G6PD Deficiency
    • Pyruvate Kinase

Pathologic (Direct/Conjugated):

• Sepsis
• TORCH Infections
• TPN
• Hypothyroid
• Galactosemia
• Tyrosinemia
• Cystic Fibrosis
• Choledochal Cyst

Question 2

JAUNDICE IN THE NEWBORN

DIAGNOSIS

Under which (5) Clinical Presentations or Lab Values is Hyperbilirubinemia considered Pathological?

Answer 2

1. Appears ON the 1st Day of Life
2. Appears AFTER the 2nd Week of Life
3. Bilirubin > 5mg/dL/day
4. Bilirubin > 12mg/dL in Term Infant
5. Direct Bilirubin > 2mg/dL at ANY time

Question 3

JAUNDICE IN THE NEWBORN

DIAGNOSIS

If Jaundice** presents in the First 24 hours, what are (5**) Tests to include in the Workup?

Answer 3

1. Bilirubin: Total & Direct
2. Blood Type (Infant & Mother):Look for ABO or Rh incompatibility
3. Direct Coombs Test
4. CBC, Reticulocyte Count, & Blood Smear:Assess for Hemolysis
5. Urinalysis & Urine Culture (if elevated Direct Bilirubin): Assess for Sepsis

Question 4

JAUNDICE IN THE NEWBORN

DIAGNOSIS

What is the Mechanism for Bilirubin in the Newborn?

Answer 4

• Hemoglobin breaks down to Unconjugated (Indirect) Bilirubin.
• Higher levels of Unconjugated Bilirubin are needed during development when it can cross the placenta and be removed from the Fetus by the Mother.
• Newborns have Low levels of Glucuronosyltransferase (the enzyme that connects or “Conjugates” Unconjugated Bilirubin to Glucose so that it can be Excreted through Feces).
• The RBCs of Newborns also have a Shorter Life Span. Breakdown of RBCs releases Unconjugated Bilirubin.

Question 5

JAUNDICE IN THE NEWBORN

DIAGNOSIS

What (4) Disorders should you consider if there is Prolonged Jaundice ( > 2 weeks ) and NO Elevation of Conjugated Bilirubin?

Answer 5

1. UTI or other Infection
2. Bilirubin Conjugation Abnormalities
   
   • Gilbert Syndrome
   • Crigler-Najjar Syndrome
3. Hemolysis
4. Intrinsic Red Cell membrane or Enzyme defects
   
   • Spherocytosis
   • Elliptocytosis
   • G6PD Deficiency
   • Pyruvate Kinase Deficiency

Question 6

JAUNDICE IN THE NEWBORN

DIAGNOSIS

What does the Most Feared Complication of Jaundice (Kernicterus) result from?

Answer 6

Elevated Indirect (Unconjugated) Bilirubin can Cross the Blood-Brain Barrier, deposit in the Basal Ganglia and Brainstem Nuclei, and cause Kernicterus.

Question 7

JAUNDICE IN THE NEWBORN

DIAGNOSIS

1. What Disorder should you consider if there is Prolonged Jaundice ( > 2 weeks ) and Elevated Conjugated Bilirubin?
2. What is the Best INITIAL Diagnostic Test for this Disorder?
3. What are the (2) Most SPECIFIC Tests for this Disorder?

Answer 7

1. Cholestasis
2. Liver Function Tests
3. Ultrasound & Liver Biopsy

Question 8

JAUNDICE IN THE NEWBORN

TREATMENT

1. What is the Best INITIAL Treatment for Jaundice in the Newborn?
2. What is the Treatment for ANY Infant with suspected Bilirubin Encephalopathy or Failure of the best initial therapy to reduce Total Bilirubin and Risk of Kernicterus?

Answer 8

1. Phototherapy when Bilirubin > 10 - 20 mg/dL (normally decreases by 2 mg/dL every 4 - 6 hours)
2. Exchange Transusion