A 3-day-old boy is in the nursery for routine evaluation. He is breastfed exclusively and is passing adequate urine and stool. He was born to a 22-year-old African American woman with an unremarkable prenatal course. Prenatal laboratory studies showed a maternal blood type O positive. The infant was delivered by repeat cesarean section at 39 weeks gestation, and his blood type is O positive. A transcutaneous bilirubin level obtained at 24 hours of life was 3.4 mg/dL, which was considered low risk. He has a healthy older sister who did not have jaundice in the newborn period. Vital signs are normal. Physical examination shows jaundice extending from the head to the thighs. The lungs are clear to auscultation. Abdominal examination reveals no tenderness, distension, or organomegaly. Laboratory results from 72 hours of life are as follows: Direct Coombs test is negative. Serum bilirubin repeated 4 hours later is 20 mg/dL, and phototherapy treatment is initiated. Which of the following is the most likely diagnosis?

Question

A 3-day-old boy is in the nursery for routine evaluation.  He is breastfed exclusively and is passing adequate urine and stool.  He was born to a 22-year-old African American woman with an unremarkable prenatal course.  Prenatal laboratory studies showed a maternal blood type O positive.  The infant was delivered by repeat cesarean section at 39 weeks gestation, and his blood type is O positive.  A transcutaneous bilirubin level obtained at 24 hours of life was 3.4 mg/dL, which was considered low risk.  He has a healthy older sister who did not have jaundice in the newborn period.  Vital signs are normal.  Physical examination shows jaundice extending from the head to the thighs.  The lungs are clear to auscultation.  Abdominal examination reveals no tenderness, distension, or organomegaly.  Laboratory results from 72 hours of life are as follows:  Direct Coombs test is negative.  Serum bilirubin repeated 4 hours later is 20 mg/dL, and phototherapy treatment is initiated.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bf5c_72b2_8f63_d193161f3258_MD0005_00 This 3-day-old African American boy has anemia and a rapidly worsening unconjugated hyperbilirubinemia, concerning for glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD deficiency is an X-linked red blood cell (RBC) enzymatic defect most commonly found in patients of African, Middle Eastern, and Southeast Asian descent. This defect increases the susceptibility of RBCs to hemolyze, which typically occurs on exposure to oxidative stress (eg, sulfa drugs, fava beans). G6PD deficiency also can result in severe unconjugated hyperbilirubinemia and anemia on day of life 2-3. The timing of jaundice development helps to differentiate G6PD deficiency from hemolytic disease of the newborn (ABO incompatibility), which presents within the first 24 hours of life and with a positive direct Coombs test, typically in an infant with blood type A or B born to a mother with blood type O (Choice A). Newborns with anemia and unconjugated hyperbilirubinemia should be tested for G6PD deficiency by directly measuring G6PD activity. Neonatal jaundice from G6PD deficiency should be treated with supportive care (eg, adequate hydration) in mild cases and phototherapy and/or exchange transfusion for more severe cases. (Choice B) Biliary atresia results from progressive destruction of the extrahepatic biliary tree. As bilirubin is conjugated in the liver and proximal to the site of obstruction, the hyperbilirubinemia in biliary atresia is direct or conjugated. (Choice C) Breast milk jaundice presents with indirect hyperbilirubinemia over the first few weeks of life and results from increased enterohepatic circulation. Breast milk jaundice rarely requires therapy, and anemia would not be expected. (Choice E) Physiologic jaundice occurs in almost every newborn due to an increased RBC count with a shorter RBC life span, decreased hepatic bilirubin clearance, and increased enterohepatic circulation. Physiologic jaundice is not associated with anemia. Educational objective: Glucose-6-phosphate dehydrogenase deficiency presents in the neonatal period on day of life 2-3 with unconjugated hyperbilirubinemia and anemia. References: Glucose-6-phosphate dehydrogenase deficiency. (http://www.ncbi.nlm.nih.gov/pubmed/27040960)

A 3-Day-Old Boy Is in the Nursery for Routine Evaluation