Is That Normal? A Case of Diagnostic Error Due to Misinterpretation of Laboratory Findings.

Abstract

A 2-month-old boy born at 37-weeks’ gestational age with no chronic medical conditions presented to the emergency department with jaundice and poor weight gain. The patient was born appropriate for gestational age, weighing 3.83 kg, and developed mild jaundice several days after birth but did not require any phototherapy. He was exclusively breastfed. He had additionally been having several episodes per day of small-volume nonbloody, nonbilious emesis daily since he was 1 week old. He had daily stools that were yellow and soft. At 5 weeks of life, the patient became jaundiced, at which time his pediatrician ordered laboratories that were notable for elevated alanine transaminase (ALT) of 59 U/L and aspartate transaminase (AST) of 158 U/L, total bilirubin of 10.4 mg/dL, direct bilirubin of 0.35 mg/dL, hemoglobin of 9.6 g/dL, reticulocyte count of 1.7%, and normal thyroid study results. In response to the laboratory abnormalities, the pediatrician referred him to an adult gastroenterologist for additional evaluation. During the appointment, at 7 weeks old, he weighed 4.58 kg (15 g/day of weight gain since birth). The gastroenterologist obtained a right upper quadrant ultrasound, which was normal, and laboratory values notable for negative hepatitis serology results, stable AST and ALT, and bilirubin with a normal gamma-glutamyl transferase, creatine kinase, and electrolytes. An α-fetoprotein (AFP) level was 3870 ng/mL (laboratory reference range of 0.6–28.3 ng/mL). Because of concern for malignancy based on the elevated AFP, outpatient oncology was consulted, and the patient was referred for a computed tomography (CT) scan of the chest, abdomen, and pelvis, which was unremarkable. In the week after his CT scan, the patient was noted to have difficulty waking for feeds overnight and …