RNC-NIC Hematology & Hyperbilirubinemia 2 — Questions and Answers
Question 1: A neonate born to a type O-positive mother is found to be type A-positive and develops jaundice at 18 hours of life. Which condition is the most likely cause?
- Physiologic jaundice
- ABO incompatibility (Correct answer)
- Rh isoimmunization
- Biliary atresia
Correct answer: ABO incompatibility
ABO incompatibility most commonly occurs when a type O mother carries a type A or B neonate; maternal anti-A IgG antibodies cross the placenta, cause hemolysis, and result in early-onset jaundice.
Question 2: Which nursing intervention is the highest priority when initiating phototherapy for a neonate with hyperbilirubinemia?
- Keep the neonate swaddled to prevent temperature instability
- Apply opaque eye patches securely to protect the retinas (Correct answer)
- Measure TSB every 12 hours regardless of clinical trajectory
- Apply moisturizing lotion to protect skin from the lights
Correct answer: Apply opaque eye patches securely to protect the retinas
Opaque eye patches must be applied correctly before starting phototherapy to protect the neonate's retinas from damage caused by the high-intensity light source.
Question 3: How does breastfeeding jaundice differ from breast milk jaundice?
- Breastfeeding jaundice peaks at days 5-15 from breast milk substances; breast milk jaundice peaks at days 2-4 from poor intake
- Breastfeeding jaundice peaks at days 2-4 from inadequate milk intake; breast milk jaundice peaks at days 5-15 from substances in mature breast milk (Correct answer)
- They are the same condition referred to by two different names
- Breast milk jaundice always requires formula supplementation while breastfeeding jaundice does not
Correct answer: Breastfeeding jaundice peaks at days 2-4 from inadequate milk intake; breast milk jaundice peaks at days 5-15 from substances in mature breast milk
Breastfeeding jaundice (days 2-4) results from insufficient caloric intake causing dehydration and increased enterohepatic circulation, while breast milk jaundice (days 5-15) is caused by substances in mature breast milk that inhibit hepatic glucuronosyltransferase.
Question 4: Intravenous immunoglobulin (IVIG) is administered to neonates with hemolytic hyperbilirubinemia to achieve which therapeutic effect?
- Directly bind and neutralize bilirubin in the bloodstream
- Block macrophage Fc receptors to reduce antibody-mediated hemolysis (Correct answer)
- Replace deficient clotting factors lost during hemolysis
- Stimulate hepatic conjugation of bilirubin
Correct answer: Block macrophage Fc receptors to reduce antibody-mediated hemolysis
IVIG occupies Fc receptors on reticuloendothelial macrophages, preventing them from destroying antibody-coated red blood cells and thereby reducing the rate of hemolysis and bilirubin production.
Question 5: A symptomatic neonate with a venous hematocrit of 72%, jitteriness, and respiratory distress is diagnosed with polycythemia. Which treatment is indicated?
- Packed red blood cell transfusion to replace lost volume
- Partial exchange transfusion using normal saline to dilute the blood (Correct answer)
- Intravenous iron dextran to correct the hematologic imbalance
- Simple phlebotomy without volume replacement
Correct answer: Partial exchange transfusion using normal saline to dilute the blood
Symptomatic polycythemia is treated with a partial exchange transfusion, removing blood and replacing it with normal saline to reduce the hematocrit to approximately 50-55% and decrease blood viscosity.
Question 6: G6PD deficiency increases a neonate's risk for severe hyperbilirubinemia primarily through which mechanism?
- Impaired hepatic conjugation of bilirubin by glucuronosyltransferase
- Increased hemolysis of red blood cells vulnerable to oxidative stress (Correct answer)
- Decreased albumin-binding capacity for unconjugated bilirubin
- Enhanced enterohepatic recirculation of excreted bilirubin
Correct answer: Increased hemolysis of red blood cells vulnerable to oxidative stress
G6PD is an enzyme critical for protecting red blood cells from oxidative damage; its deficiency causes hemolysis when cells are exposed to oxidative stressors, increasing bilirubin production.
Question 7: According to AAP guidelines, when is exchange transfusion indicated for a term neonate with hyperbilirubinemia?
- Any TSB of 12 mg/dL or greater within the first 48 hours
- TSB at or above the exchange transfusion threshold on the Bhutani nomogram, especially with signs of encephalopathy (Correct answer)
- Positive DAT regardless of the current TSB level
- TSB of 15 mg/dL or greater within the first 24 hours
Correct answer: TSB at or above the exchange transfusion threshold on the Bhutani nomogram, especially with signs of encephalopathy
Exchange transfusion is indicated when TSB meets the exchange threshold on the AAP nomogram based on gestational age and risk factors, or when acute bilirubin encephalopathy is present despite intensive phototherapy.
RNC-NIC Hematology & Hyperbilirubinemia 2
A neonate born to a type O-positive mother is found to be type A-positive and develops jaundice at 18 hours of life.
Which condition is the most likely cause?