NNP Hematology and Hyperbilirubinemia

Question 1

Which enzyme is responsible for converting heme to biliverdin in the catabolism of hemoglobin?

Accepted Answer

Heme oxygenase

Answer

Biliverdin reductase

Answer

UDP-glucuronosyltransferase

Answer

Glutathione peroxidase

Question 2

A term neonate develops jaundice at 18 hours of age. Which of the following is the MOST likely cause?

Accepted Answer

ABO incompatibility hemolytic disease

Answer

Breast milk jaundice

Answer

Physiologic jaundice

Answer

Crigler-Najjar syndrome type II

Question 3

At what gestational age does fetal hemoglobin (HbF) begin to be replaced by adult hemoglobin (HbA)?

Accepted Answer

After 34–36 weeks gestation

Answer

20–24 weeks gestation

Answer

28–32 weeks gestation

Answer

32–34 weeks gestation

Question 4

Which of the following best describes physiologic jaundice in a term neonate?

Accepted Answer

Onset after 24 hours, peak by day 3–4, resolves by day 14

Answer

Onset within 24 hours, peak by day 2

Answer

Onset after 24 hours, persistent beyond 3 weeks

Answer

Onset at day 5–7, associated with breastfeeding difficulty

Question 5

A 3-day-old breastfed neonate has a total serum bilirubin (TSB) of 18 mg/dL. The mother reports the infant is nursing 8–10 times per day with adequate wet diapers. What is the MOST appropriate next step?

Accepted Answer

Begin phototherapy based on hour-specific nomogram

Answer

Discontinue breastfeeding and start formula

Answer

Perform exchange transfusion immediately

Answer

Obtain a direct Coombs test only and observe

Question 6

Which of the following maternal blood types places a neonate at highest risk for significant ABO hemolytic disease?

Accepted Answer

Type O mother with type A or B infant

Answer

Type A mother with type B infant

Answer

Type B mother with type O infant

Answer

Type AB mother with type A infant

Question 7

What is the primary mechanism by which phototherapy reduces serum bilirubin levels?

Accepted Answer

Converts unconjugated bilirubin to water-soluble photoisomers excreted without conjugation

Answer

Enhances hepatic UDP-glucuronosyltransferase activity

Answer

Increases intestinal motility to reduce enterohepatic circulation

Answer

Promotes renal excretion of unconjugated bilirubin