RNC-NIC Hematology & Hyperbilirubinemia 1 — Questions and Answers
Question 1: A term neonate at 36 hours of life has a total serum bilirubin (TSB) of 13 mg/dL, placing it in the high-intermediate risk zone on the Bhutani nomogram. Which intervention is most appropriate?
- Initiate intensive phototherapy immediately
- Repeat TSB in 4-6 hours and monitor the trajectory closely (Correct answer)
- Perform exchange transfusion
- Discharge with pediatric follow-up in one week
Correct answer: Repeat TSB in 4-6 hours and monitor the trajectory closely
In the high-intermediate risk zone, close monitoring with repeat TSB in 4-6 hours is appropriate to assess the rate of rise before escalating to phototherapy.
Question 2: Which form of bilirubin is considered neurotoxic in the neonate because it can cross the blood-brain barrier?
- Conjugated (direct) bilirubin
- Unconjugated (indirect) bilirubin (Correct answer)
- Delta bilirubin
- Urobilirubin
Correct answer: Unconjugated (indirect) bilirubin
Unconjugated bilirubin is lipid-soluble and can cross the blood-brain barrier, depositing in the basal ganglia and causing bilirubin encephalopathy.
Question 3: A 3-day-old neonate exhibits lethargy, hypotonia, a high-pitched cry, and opisthotonus (arching). These findings are most consistent with which complication of severe hyperbilirubinemia?
- Neonatal sepsis
- Acute bilirubin encephalopathy (kernicterus) (Correct answer)
- Hypoglycemia
- Hypocalcemia
Correct answer: Acute bilirubin encephalopathy (kernicterus)
Acute bilirubin encephalopathy presents with these classic neurological signs caused by unconjugated bilirubin depositing in the basal ganglia and brainstem.
Question 4: A positive direct antiglobulin test (DAT/direct Coombs test) in a neonate most strongly suggests which condition?
- ABO incompatibility or Rh hemolytic disease of the newborn (Correct answer)
- Physiologic jaundice
- Breast milk jaundice
- Gilbert syndrome
Correct answer: ABO incompatibility or Rh hemolytic disease of the newborn
A positive DAT indicates maternal IgG antibodies are coating the neonate's red blood cells, which is characteristic of ABO or Rh isoimmunization causing hemolytic disease.
Question 5: Physiologic jaundice in a healthy term neonate typically becomes visible on which day of life?
- Day 1
- Days 2-3 (Correct answer)
- Days 5-7
- Day 10
Correct answer: Days 2-3
Physiologic jaundice appears on days 2-3 as bilirubin accumulates from normal red blood cell turnover; jaundice visible within the first 24 hours is always considered pathologic.
Question 6: Which laboratory value defines polycythemia in the neonate?
- Hemoglobin greater than 18 g/dL
- Central venous hematocrit of 65% or greater (Correct answer)
- Platelet count greater than 450,000/mm³
- White blood cell count greater than 30,000/mm³
Correct answer: Central venous hematocrit of 65% or greater
Neonatal polycythemia is defined as a central venous hematocrit of 65% or higher, which significantly increases blood viscosity and can impair organ perfusion.
Question 7: A 28-week preterm neonate on day 21 of life has a hemoglobin of 7 g/dL with associated tachycardia and poor weight gain. Which intervention is most appropriate?
- Iron supplementation alone
- Packed red blood cell (PRBC) transfusion (Correct answer)
- Erythropoietin administration without transfusion
- Vitamin K injection
Correct answer: Packed red blood cell (PRBC) transfusion
Symptomatic anemia of prematurity with hemoglobin at or below 7-8 g/dL accompanied by clinical signs of hemodynamic compromise is a standard indication for PRBC transfusion.
RNC-NIC Hematology & Hyperbilirubinemia 1
A term neonate at 36 hours of life has a total serum bilirubin (TSB) of 13 mg/dL, placing it in the high-intermediate risk zone on the Bhutani nomogram.
Which intervention is most appropriate?