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The answer is c. Although similar to cow’s milk in composition, goat’s milk is very low in folic acid. Infants fed with goat’s milk exclusively are susceptible to megaloblastic anemia resulting from folate deficiency.

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The answer is b. Vegetarians who consume eggs are known as ovo-vegetarians; those who consume dairy products are called lactovegetarians; and those who consume both are known as lacto-ovo-vegetarians. Vegetarians who consume neither eggs nor dairy products are called vegans. This diet contains almost no vitamin B₁₂; therefore, vegans are at high risk for
developing a deficiency state. Nursing vegan mothers must be given supplemental vitamin B₁₂ to prevent the development of methylmalonic acidemia in their infants. (Adenosylcobalamin, a metabolite of vitamin B₁₂, serves as a coenzyme in the metabolism of methylmalonic acid. Deficiency of vitamin B₁₂ can, therefore, lead to methylmalonic acidemia characterized by ketosis, acidosis, anemia, neutropenia, thrombocytopenia, hyperammonemia, coma, and death.)

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The answer is d. Vitamin E (α-tocopherol) is a fat-soluble antioxidant that is present in milk and in a wide variety of foods. Supplementation is necessary in only select conditions such as in preterm infants who demonstrate poor absorption and in clinical conditions leading to fat malabsorption (biliary atresia, cystic fibrosis, pancreatic insufficiency, short bowel syndrome). Clinical manifestations of vitamin E deficiency include progressive neurologic degeneration such as cerebellar ataxia, peripheral neuropathy, posterior column abnormalities with loss of deep tendon reflexes, and weakness.

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The answer is e. Bilious emesis without abdominal distention is the most typical presentation of congenital duodenal obstruction. The relative incidence of various forms of congenital duodenal obstruction is duodenal atresia in 42%, annular pancreas in 33%, and duodenal diaphragm in 23% of neonates. Down syndrome is present in up to 30% of infants with duodenal atresia. Polyhydramnios occurs in approximately 50% of pregnancies in which there is congenital duodenal obstruction. This occurs because high intestinal obstruction prevents the normal absorption of amniotic fluid in the distal small intestine. The radiographic finding of a markedly distended stomach and first portion of the duodenum without air in the bowel distal to this is known as the double-bubble sign and is pathognomonic of duodenal atresia (see Fig. 63.3).

Pyloric stenosis is typically not present at birth, but presents between 3 weeks and 5 months of age. Emesis with this condition is nonbilious, as the obstruction is proximal to the second portion of the duodenum, where bile enters the lumen of the gut. A midgut volvulus is also not typically present at birth. This should always be considered in the differential diagnosis of any infant that initially does well for several days to several months of life and subsequently develops bilious emesis. Hirschsprung disease may present with bilious emesis; however, the patient’s abdomen would be markedly distended because of the distal location of the obstruction. For the same reason, the presentation is not consistent with ileal duplication; as such a distal obstruction would result in significant abdominal distension. The ileum is the most common location for GI duplication cysts. The presentation is typically in childhood or adulthood.

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The answer is a. Intestinal malrotation is a congenital anomaly occurring in approximately 1 in 500 live births. It results from failure of the normal 270-degree counterclockwise rotation of the midgut around the superior mesenteric artery during fetal development. Symptoms may be intermittent and chronic or acute and catastrophic. Approximately 50% of infants with this condition will develop symptoms in the first month, whereas 90% become symptomatic within the first year of life. Vomiting is the most common presenting sign and is bilious in over 80% of patients. The diagnostic test of choice is an upper GI series. Because intestinal malrotation with midgut volvulus can rapidly lead to irreversible intestinal ischemia and death, every individual in whom this anomaly is clinically suspected should have an immediate upper GI study.

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The answer is b. Infants born to mothers with insulindependent diabetes mellitus are at up to an eightfold increased risk of congenital malformation as compared with infants born to mothers without this condition. Associated GI malformations include a small or hypoplastic left colon syndrome, also referred to as functional immaturity of the colon. In addition, there is an increased incidence of duodenal and anorectal atresia.

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The answer is c. A moderate decrease in serum levels of factors II, VII, IX, and × normally occurs in all newborns by 72 hours following delivery. This deficiency of vitamin K-dependent factors is secondary to lack of free vitamin K in the mother as well as breast milk (a poor source of vitamin K) and absence of bacterial intestinal flora normally responsible for production of vitamin K. Maternal medications, including anticonvulsants (phenobarbital, phenytoin) and antituberculous medications (isoniazid [INH] and rifampin) have been identified as risk factors for hemorrhagic disease of the newborn. Administration of 1 mg of natural oil-soluble vitamin K (phylloquinone) intramuscularly to the newborn at the time of delivery prevents the fall in vitamin K-dependent factors in full-term infants. In the clinical scenario, the delivery at home implies that no prophylactic vitamin K was administered. This was followed by the development of classic hemorrhagic disease of the newborn. Sites of hemorrhage with this condition include the GI tract and the intracranial, circumcision, cutaneous, and injection sites.