A 4-week-old girl is brought to the clinic for post-hospitalization follow-up. Her mother moved from Greece to the United States for a diplomatic position a few months prior to giving birth. The patient was born at term, and the mother's prenatal course and delivery were uncomplicated. Due to hyperbilirubinemia, the patient was in the nursery for 3 weeks of phototherapy. Bilirubin was normal at discharge. Since discharge, the girl's skin and eyes have remained yellow. Maternal blood type is AB, Rh-D positive. Infant blood type is A, Rh-D positive. The patient has been breastfeeding exclusively. Weight and length were at the 50th percentile at 2 weeks of age and remain at the 50th percentile today. Laboratory results today are as follows: Which of the following is the most likely cause of this patient's condition?

Question

A 4-week-old girl is brought to the clinic for post-hospitalization follow-up.  Her mother moved from Greece to the United States for a diplomatic position a few months prior to giving birth.  The patient was born at term, and the mother's prenatal course and delivery were uncomplicated.  Due to hyperbilirubinemia, the patient was in the nursery for 3 weeks of phototherapy.  Bilirubin was normal at discharge.  Since discharge, the girl's skin and eyes have remained yellow.  Maternal blood type is AB, Rh-D positive.  Infant blood type is A, Rh-D positive.  The patient has been breastfeeding exclusively.  Weight and length were at the 50th percentile at 2 weeks of age and remain at the 50th percentile today.  Laboratory results today are as follows:  Which of the following is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d6a2_72fe_bc81_21201cdee3ee_MD0003_00 This infant has jaundice, hemolytic anemia, and elevated mean corpuscular hemoglobin concentration (MCHC) consistent with hereditary spherocytosis (HS). HS is due to an inherited defect in red blood cell (RBC) membrane proteins (eg, spectrin, ankyrin), which results in fragile, sphere-shaped RBCs that become trapped and hemolyzed in the spleen. Newborns with HS often have hyperbilirubinemia that requires phototherapy. Although physiologic jaundice is expected in the first week of life due to increased RBC turnover (shorter fetal RBC lifespan) and decreased bilirubin clearance, severe or prolonged neonatal jaundice (>1 week) raises suspicion for inherited hemolytic anemia. Reticulocytosis on bloodwork confirms hemolysis, and elevated MCHC reflects spherocytosis due to membrane loss and RBC dehydration. Other laboratory findings include low to normal mean corpuscular volume, negative direct Coombs test, and spherocytes on peripheral smear. Treatment is primarily supportive. RBC or exchange transfusion may be considered for infants with severe hemolysis. (Choice A) ABO incompatibility refers to hemolysis when a mother with blood type O transfers anti-A and/or anti-B antibodies to her fetus with a nonmatching blood type (ie, A, B, AB). In this case, maternal blood type is AB; therefore, the mother has no anti-A or anti-B antibodies to cause hemolysis of fetal RBCs. ABO incompatibility (Choice B) Beta thalassemia is caused by a defect in the beta globin chain. It is common among patients of Mediterranean heritage and can result in microcytic, nonimmune, hemolytic anemia. However, it does not typically present until after age 6 months when fetal hemoglobin decreases. In addition, MCHC is usually decreased in beta thalassemia. (Choice C) Breastfeeding failure jaundice presents in the first week of life with indirect, nonhemolytic hyperbilirubinemia due to inadequate breastmilk intake, resulting in significant weight loss. This patient's jaundice has persisted despite appropriate weight gain. (Choice D) Glucose-6-phosphate dehydrogenase (G6PD) deficiency can cause hemolysis and prolonged jaundice in the newborn period but is an X-linked disorder more commonly seen in male patients. In addition, MCHC is typically normal in G6PD deficiency. Educational objective: Hereditary spherocytosis (HS) is an inherited disorder caused by a defect in red blood cell membrane proteins, leading to spherocyte formation and hemolysis. Hemolytic anemia with an elevated mean corpuscular hemoglobin concentration in an infant with prolonged neonatal jaundice is suggestive of HS. References: Hereditary spherocytosis in the neonatal period: a case report. (http://www.ncbi.nlm.nih.gov/pubmed/28847351) A pediatrician's practical guide to diagnosing and treating hereditary spherocytosis in neonates. (http://www.ncbi.nlm.nih.gov/pubmed/26009624)

A 4-Week-Old Girl Is Brought to the Clinic for Post-Hospitalization