Case 2: A Patient with Trisomy 21, Transient Abnormal Myelopoiesis, and Pneumoperitoneum

Abstract

A 34-week-gestation male infant is born appropriate for gestational age to a 41-year-old gravida 3, para 3 woman. The patient’s mother had received limited prenatal care starting at 15 weeks, and is found to have a positive result on maternal serum α-fetoprotein screening test and an amniocentesis that confirms trisomy 21 (47,XY+21 karyotype) with no evidence of translocation or mosaicism. The infant is born at an outside hospital and has physical features characteristic of trisomy 21. He is transferred to our facility for respiratory distress and multiple episodes of apnea and bradycardia on the day of birth. Sepsis is ruled out on admission. His initial complete blood cell count is significant for a white blood cell count of 15,300/μL (15.3×109/L) with 25% blasts. He is also noted to have an enlarged liver that is 1 cm below the costal margin. Peripheral blood smear and flow cytometry findings are consistent with a diagnosis of transient abnormal myelopoiesis (TAM). Pediatric hematology is consulted and recommends complete blood cell counts which are obtained regularly until day 22 after birth, when the TAM spontaneously resolves. The infant is able to receive full enteral feedings until he develops abdominal distention and irritability on day 12 after birth. An abdominal radiograph is notable for pneumoperitoneum concerning for an acute bowel perforation without signs of …