Intermittent Tachypnea in the Newborn

A male infant is born at 38 weeks, 4 days of gestation via spontaneous vaginal delivery to a 20-year-old gravida 4, para 2-0-2-2 woman. The maternal history is significant for substance abuse of cocaine, inadequate prenatal care, iron-deficiency anemia, and newly diagnosed and untreated human immunodeficiency virus (HIV) infection with a viral load of 658 copies/mL. Her medical history includes a repaired congenital ventricular septal defect at the age of 4 years. The infant is vigorous at birth and admitted to the NICU for HIV antiretroviral drug therapy because of the untreated maternal HIV infection. The infant is hemodynamically stable during the first 72 hours after birth and starts having tachypnea on day 3, with respiratory rates ranging from 70 to 90 breaths/min; all his other vital signs are within normal limits. Physical examination findings are unremarkable, with no retractions, no adventitious lung sounds, or cardiac murmurs. The infant requires no respiratory support. Initial chest radiography shows diffuse perihilar interstitial markings and mild ground glass appearance (Fig 1). Because of persistent tachypnea, 2-dimensional (2D) transthoracic echocardiography (Echo) and electrocardiography (EKG) are performed on day 4. EKG shows normal sinus rhythm with rightward axis deviation (normal for age) and no ST/T wave changes. The 2D Echo is significant for the left anterior descending (LAD) coronary artery draining into right ventricle and significantly dilated left main and left anterior coronary arteries (Figs 2, 3, and 4). Follow-up Echo shows worsening of the condition, for which serial cardiac troponins levels are measured. The troponin level is initially normal and then starts to increase as follows: …