A -week-old, A-positive, African-American former -week’s-gestational-age infant was born to an O-positive mother and experienced hyperbilirubinemia requiring days of phototherapy on the newborn nursery after birth The infant appears apathetic and demonstrates pallor, a grade /6 systolic ejection murmur, and a heart rate of 7 The most likely diagnosis is

Correct Answer: D

Rationale: Continued hemolysis due to ABO incompatibility can lead to anemia, jaundice, and cardiac symptoms

Correct Answer: B

Rationale: Renal tubular acidosis causes normal anion gap acidosis because it results from impaired renal acid excretion rather than accumulation of organic acids.

Correct Answer: D

Rationale: Intestinal pseudo-obstruction can lead to polyhydramnios due to impaired fetal swallowing and gastrointestinal motility. The other conditions are not typically associated with excess amniotic fluid.

Correct Answer: C

Rationale: Around 3 months of age, an infant begins to recognize familiar faces and objects, including a feeding bottle.

Correct Answer: D

Rationale: Rubella is strongly associated with intracranial calcifications in affected infants. Other infections like cytomegalovirus and syphilis may also cause calcifications but are less characteristic.