A newborn is evaluated in the delivery room for respiratory distress. The patient was born at 37 weeks gestation via vaginal delivery to a mother whose pregnancy was notable for poorly controlled gestational diabetes. Labor was complicated by shoulder dystocia, and birth weight was at the 99th percentile for age. Apgar scores were 4 and 6 at 1 and 5 minutes, respectively. Temperature is 37 C (98.6 F), pulse is 150/min, and respirations are 75/min. Oxygen saturation is 95% on room air. The patient is in mild respiratory distress with subcostal retractions. There is right midshaft clavicular crepitus with normal movement and tone of both upper extremities. Cardiac examination shows a 3/6 systolic ejection murmur. Echocardiogram reveals a small left ventricular cavity and increased interventricular septal wall thickness. Which of the following is the most likely outcome for this patient's cardiac abnormality?

Question

A newborn is evaluated in the delivery room for respiratory distress.  The patient was born at 37 weeks gestation via vaginal delivery to a mother whose pregnancy was notable for poorly controlled gestational diabetes.  Labor was complicated by shoulder dystocia, and birth weight was at the 99th percentile for age.  Apgar scores were 4 and 6 at 1 and 5 minutes, respectively.  Temperature is 37 C (98.6 F), pulse is 150/min, and respirations are 75/min.  Oxygen saturation is 95% on room air.  The patient is in mild respiratory distress with subcostal retractions.  There is right midshaft clavicular crepitus with normal movement and tone of both upper extremities.  Cardiac examination shows a 3/6 systolic ejection murmur.  Echocardiogram reveals a small left ventricular cavity and increased interventricular septal wall thickness.  Which of the following is the most likely outcome for this patient's cardiac abnormality?

Quizplus · Accepted Answer

11ec25c8_d633_d2d2_bc81_131c18111a72_MD0003_00 This newborn of a diabetic mother has respiratory distress with a systolic murmur and a thickened interventricular septum, findings consistent with hypertrophic cardiomyopathy (HCM). HCM is a potential neonatal complication of maternal diabetes (usually when poorly controlled) caused by increased glycogen and fat deposition in myocardial cells, particularly within the interventricular septum, leading to interventricular septum thickening and a small left ventricular cavity. Increased fat deposition also leads to macrosomia and associated complications, including shoulder dystocia and clavicle fracture (eg, clavicular crepitus). hypertrophic cardiomyopathy Although most cases of HCM in infants of diabetic mothers are asymptomatic, left ventricular outflow tract (LVOT) obstruction can lead to poor cardiac output with hypotension and respiratory distress (eg, tachypnea, retractions). A systolic ejection murmur is characteristic and represents LVOT obstruction. Initial management includes beta-blocker therapy to decrease cardiac contractility and increase left ventricular filling time, both of which lessen the dynamic LVOT obstruction and improve cardiac output. However, HCM in these patients is transient as insulin levels normalize in the first few weeks of life, and medical management is rarely required beyond the neonatal period. Spontaneous regression of echocardiographic findings occurs by age 1. (Choices A, C, and D) Hypoplastic left heart syndrome (HLHS), which is not associated with maternal diabetes, is characterized by underdevelopment of the left side of the heart. Initial management includes prostaglandin infusion to maintain patency of the ductus arteriosus. Staged palliative repair should occur in infancy, and transplantation may be indicated for heart failure that is refractory to medical therapy and surgical palliation. Although left ventricular hypertrophy can occur in this condition, isolated hypertrophy of the interventricular septum is not expected. In addition, although HLHS causes respiratory distress, cyanosis is always present and not seen here. Hypoplastic left heart syndrome (HLHS) (Choice B) Corrective surgery is often required in cases of fixed LVOT obstruction, such as aortic stenosis, which also causes a systolic ejection murmur. However, echocardiography would show abnormal aortic valve morphology or mobility, not thickening of the interventricular septum. Educational objective: Transient hypertrophic cardiomyopathy may be seen in infants of diabetic mothers due to myocardial fat and glycogen deposition. Left ventricular outflow tract obstruction causes a systolic ejection murmur with or without hypotension and respiratory distress. Characteristic echocardiographic findings of a thickened interventricular septum spontaneously regress by age 1 due to normalization of insulin levels. References: Fetal cardiac functional abnormalities assessed by echocardiography in mothers suffering gestational diabetes mellitus: A systematic review and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/32861465)

A Newborn Is Evaluated in the Delivery Room for Respiratory