You are evaluating a 3-day-old 1,300-g infant who was born at 30 weeks’ gestation. He did not have early respiratory distress. He has been receiving intravenous nutrition and slowly started enteral feedings yesterday. Today he has several episodes of apnea lasting 20 to 30 seconds that are associated with cyanosis (pulse oximetry reading of 75%) and bradycardia (heart rate of 75 beats/min). He has responded to tactile stimulation and blow-by oxygen. Physical examination after one such episode reveals good color, perfusion, tone, and reactivity. The lungs are clear, and the chest wall is stable. There is no heart murmur. The abdomen is soft and non-tender, with normal bowel sounds.



Of the following, the MOST likely cause of the apnea episodes in this infant is

You are called to examine a newborn male who weighs 2,480 g after a gestation of 42 weeks. The physical examination reveals a normocephalic head, a positive red reflex bilaterally, clear lung fields upon auscultation, no heart murmur, and a soft abdomen without palpable visceromegaly.



Of the following, the MOST likely additional physical finding expected for this post term infant is

1.       A newborn has hepatosplenomegaly, purpuric rash, jaundice, thrombocytopenia, and microcephaly. Computed tomography of the head demonstrates diffuse cerebral calcifications.



Of the following, the MOST appropriate diagnostic testing for this infant includes:

You are called to see a newborn who appears to be a male and has a well-developed rugated scrotum without palpable testes. The phallus is 3.5 cm in length, but there is hypospadias extending to the base of the phallus and what seems to be an open urogenital sinus. It is hard to determine whether there is a separate urethral opening. On reviewing the maternal records, you discover that prenatal amniocentesis obtained because of advanced maternal age showed an XX chromosome pattern. You arrange a complete initial evaluation for a potential disorder of sexual differentiation.



Of the following, the MOST important initial test to obtain for this child is

A large-for-gestational age newborn girl who was born via caesarean section for breech presentation is ready for discharge from the newborn nursery at 72 hours of age. She has had an entirely normal newborn course.



Of the following, you are MOST likely to advise the mother that her infant is at increased risk for