Hereditary Spherocytosis in the Newborn
A term newborn develops jaundice at 12 hours. At 36 hours total bilirubin is 285 µmol/L, direct fraction 12 µmol/L, hemoglobin 118 g/L, reticulocytes 9 percent, and mean corpuscular hemoglobin concentration 375 g/L. The direct antiglobulin test is negative and the blood film shows dense round red cells without central pallor. His father had a splenectomy as a teenager for anemia. What is the most likely cause of the hyperbilirubinemia?
- A.Glucose-6-phosphate dehydrogenase deficiency
- B.Physiologic jaundice of the newborn
- C.Extrahepatic biliary atresia
- D.Hereditary spherocytosisCorrect
Explanation
Jaundice appearing in the first 24 hours is always pathologic and points to hemolysis. The combination of spherocytes on film, an elevated mean corpuscular hemoglobin concentration above about 360 g/L, reticulocytosis, a negative direct antiglobulin test, and a family history of splenectomy is essentially diagnostic of hereditary spherocytosis. The disorder arises from defects in the vertical linkage proteins of the red cell membrane, most often ankyrin, spectrin, or band 3, which cause loss of membrane surface area, a spheroidal cell shape, and premature splenic destruction. A raised mean corpuscular hemoglobin concentration is the single most useful automated clue because the cell loses membrane but keeps its hemoglobin, and it is the finding that separates spherocytosis from other hemolytic causes. Glucose-6-phosphate dehydrogenase deficiency is a very common cause of neonatal jaundice in Saudi Arabia, but its film shows bite cells, blister cells, and Heinz bodies rather than uniform spherocytes, and mean corpuscular hemoglobin concentration is not elevated. ABO incompatibility can also produce spherocytes but requires a setup such as a group O mother with a group A or B infant, and here both are group O with a negative antiglobulin test. Physiologic jaundice never begins before 24 hours and is not associated with anemia or reticulocytosis. Biliary atresia causes conjugated hyperbilirubinemia with pale stools at 2 to 8 weeks of age, not unconjugated jaundice on day 1. Confirmation is by eosin-5-maleimide binding flow cytometry, and management includes phototherapy, folate supplementation, monitoring for aplastic crisis with parvovirus B19, and splenectomy for severe disease.
Why each option
- A.
- G6PD deficiency is common regionally but produces bite and blister cells with Heinz bodies and does not raise the mean corpuscular hemoglobin concentration.
- B.
- Physiologic jaundice appears after 24 hours, peaks at day 3 to 5, and does not cause anemia, spherocytes, or reticulocytosis.
- C.
- Biliary atresia causes conjugated hyperbilirubinemia with acholic stools weeks after birth, not day-one unconjugated jaundice.
- D.
- Correct. Spherocytes with a high mean corpuscular hemoglobin concentration, negative antiglobulin test, and positive family history define hereditary spherocytosis.
Reference: Nelson Textbook of Pediatrics, 22nd ed., 2024, Hemolytic Anemias; UpToDate 2025, Hereditary spherocytosis
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