A 7-day-old African American boy is being evaluated in the hospital. He was admitted yesterday due to sepsis after being brought to the emergency department with fever and vomiting. The patient is receiving intravenous antibiotics, and blood cultures grew Escherichia coli. He had been breastfeeding prior to admission, but feeds are being held due to vomiting. The patient was born at term, and there were no complications during the pregnancy and delivery. Temperature is 38.2 C (100.8 F) and pulse is 158/min. Examination shows jaundice. The liver is palpable 4 cm below the costal margin. Laboratory results are as follows: Which of the following is the most likely cause for this patient's condition?

Question

A 7-day-old African American boy is being evaluated in the hospital.  He was admitted yesterday due to sepsis after being brought to the emergency department with fever and vomiting.  The patient is receiving intravenous antibiotics, and blood cultures grew Escherichia coli.  He had been breastfeeding prior to admission, but feeds are being held due to vomiting.  The patient was born at term, and there were no complications during the pregnancy and delivery.  Temperature is 38.2 C (100.8 F) and pulse is 158/min.  Examination shows jaundice.  The liver is palpable 4 cm below the costal margin.  Laboratory results are as follows:  Which of the following is the most likely cause for this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d65e_1675_bc81_f71fad92d180_MD0003_00 This patient's presentation is consistent with galactosemia, an autosomal recessive disorder caused by galactose-1-phosphate uridylyltransferase (GALT) deficiency. Deficiency results in an inability to metabolize galactose to glucose, leading to galactose accumulation in tissues. galactose-1-phosphate uridylyltransferase (GALT) deficiency Symptoms of poor feeding and vomiting develop in the first few days of life after the introduction of galactose, which is found in breast milk and cow's milk-based formula. Galactose accumulation also leads to jaundice and hepatomegaly (hepatic dysfunction), and cataract formation may occur. Because excessive galactose can impair leukocyte function and superoxide release, patients are also at increased risk for Escherichia coli sepsis, which may be the initial presentation of galactosemia in some neonates. Supportive laboratory findings include hypoglycemia, metabolic acidosis (from renal tubular damage due to galactose accumulation), elevated transaminases, and conjugated and/or unconjugated hyperbilirubinemia. Although elevated direct bilirubin reflects hepatic involvement, unconjugated hyperbilirubinemia is likely due to the accumulation of galactose 1-phosphate in red blood cells (RBCs), promoting erythrocyte death (ie, hemolytic anemia). Absent RBC GALT activity confirms the diagnosis. Treatment is dietary elimination of galactose by using a soy-based formula. (Choice B) Glucose-6-phosphate dehydrogenase deficiency is characterized by inadequate NADPH production and can cause neonatal jaundice (due to unconjugated hyperbilirubinemia) and hemolytic anemia. However, this patient's E coli sepsis and elevated transaminases make this diagnosis less likely than galactosemia. (Choice C) Wiskott-Aldrich syndrome is an immunodeficiency disorder caused by a loss-of-function mutation in the WAS gene. Patients are predisposed to recurrent infections but have eczema and thrombocytopenia. This patient's platelet count is normal. (Choice D) Spherocytosis, which causes jaundice and hemolytic anemia, is due to a mutation in the proteins (eg, spectrin, ankyrin) linking the RBC membrane to its cytoskeleton. Laboratory evaluation would show normal transaminases and increased mean corpuscular hemoglobin concentration, findings not seen in this patient. (Choice E) Although sickle cell disease can cause hemolytic anemia and jaundice (due to unconjugated hyperbilirubinemia), its presentation typically occurs after age 6 months, when gamma chain (found in fetal hemoglobin) production decreases and beta-globin chain production increases. Hepatomegaly and elevated transaminases would not be expected. beta-globin chain production Educational objective: Galactosemia is characterized by the inability to metabolize galactose (found in breast and cow's milk) to glucose, resulting in galactose accumulation and hypoglycemia. Patients may have vomiting, jaundice, hepatomegaly, and Escherichia coli sepsis. Hyperbilirubinemia may be conjugated (ie, liver dysfunction) and/or unconjugated (ie, hemolytic anemia). References: Early and severe indirect hyperbilirubinemia as a manifestation of galactosemia. (http://www.ncbi.nlm.nih.gov/pubmed/20351709) Galactosemia presenting as recurrent sepsis. (http://www.ncbi.nlm.nih.gov/pubmed/21321007)

A 7-Day-Old African American Boy Is Being Evaluated in the Hospital