ANSWERS: Pediatric MCQs of the WEEK

ANSWERS: Pediatric MCQs of the WEEK

MCQ#01

Correct Answer: (D) 

Although jitteriness in neonates can result from abnormalities of each of the possible answers, this infant has qualities that make hypoglycemia the most likely cause. The size of the infant is well above the 90th percentile for newborn males. Many causes of macrosomia (eg, previous large-for-gestational age infants and maternal diabetes) are associated with abnormal glucose metabolism. The additional findings of ear anomalies could implicate a calcium abnormality (eg, DiGeorge anomaly/sequence), but the child has no heart murmur and is not failing to thrive at this point, making this a less likely diagnosis.

MCQ#02

Correct Answer: (E) 

There is a well-known association of Beckwith-Wiedemann syndrome (BWS) with hypoglycemia affecting up to 50% of children with the disorder. Physical findings are characterized by macrosomia, microcephaly, visceromegaly, and macroglossia. Other associated anomalies are an increased incidence of hemihypertrophy, omphaloceles, cryptorchidism, and renal tumors. The ear pits or creases are not always present in affected patients but are highly characteristic of BWS. Transmission is often from a sporadic mutation on chromosome 11p15, although autosomal dominant inheritance is also seen. The frequency of occurrence is 1:15,000, with variable expression. Mild to moderate mental deficiency has been reported in this disorder and is thought to be related to neonatal hypoglycemia. The other syndromes are not associated with hypoglycemia.

MCQ#03

Correct Answer: (A) 

The exact etiology of hypoglycemia in a neonate can be difficult to determine and involves a differential that is very different from that seen in an older infant, child, or adult. Small–for-gestational-age infants and premature infants both have increased incidence of symptomatic hypoglycemia. Amajority of their glucose problems are related to deficient glycogen stores, muscle protein, and body fat needed for metabolization to meet energy requirements.

Infants born to diabetic mothers also experience an increased incidence of hypoglycemia. However, hypoglycemia in infants of diabetic mothers is not due to insufficient stores, but is due to hyperinsulinemia and low glucagon levels. Beckwith-Wiedemann syndrome infants also experience hyperinsulinemia which causes hypoglycemia. Their increased insulin secretion is caused by pancreatic islet cell hypertrophy.

Treatment for these infants is the same as for other causes of hyperinsulinism; supportive administration of intravenous glucose at a rate of 6–8 mg/kg/min. At times, more aggressive treatments are warranted (eg, increased rates of glucose administration and supplementation of regulatory hormones by injections of steroids and growth hormone).