A 4-week-old boy is being evaluated in the neonatal intensive care unit. The patient was born at 31 weeks gestation to a 26-year-old primigravida via spontaneous vaginal delivery. The mother had an uneventful pregnancy prior to the onset of labor. At delivery, the patient had breathing difficulty and required mechanical ventilation until age 4 days, when he was weaned to nasal cannula. He also received intravenous antibiotics until cultures were sterile at 36 hours. In addition, the patient has been receiving total parenteral nutrition exclusively since birth. Enteral feeds were introduced today, and weight has been stable at the 75th percentile for gestational age. Temperature is 37.4 C (99.3 F), pulse is 130/min, and respirations are 38/min. Pulse oximetry is 90% on 3 L/min of oxygen through a nasal cannula at 40% fraction of inspired oxygen. Examination reveals mild subcostal retractions and bilateral faint crackles. Cardiac examination is unremarkable. The abdomen is mildly protuberant but soft. Bowel sounds are present. This patient is at highest risk for developing which of the following complications?

Question

A 4-week-old boy is being evaluated in the neonatal intensive care unit.  The patient was born at 31 weeks gestation to a 26-year-old primigravida via spontaneous vaginal delivery.  The mother had an uneventful pregnancy prior to the onset of labor.  At delivery, the patient had breathing difficulty and required mechanical ventilation until age 4 days, when he was weaned to nasal cannula.  He also received intravenous antibiotics until cultures were sterile at 36 hours.  In addition, the patient has been receiving total parenteral nutrition exclusively since birth.  Enteral feeds were introduced today, and weight has been stable at the 75th percentile for gestational age.  Temperature is 37.4 C (99.3 F), pulse is 130/min, and respirations are 38/min.  Pulse oximetry is 90% on 3 L/min of oxygen through a nasal cannula at 40% fraction of inspired oxygen.  Examination reveals mild subcostal retractions and bilateral faint crackles.  Cardiac examination is unremarkable.  The abdomen is mildly protuberant but soft.  Bowel sounds are present.  This patient is at highest risk for developing which of the following complications?

Quizplus · Accepted Answer

11ec25c8_d720_7c83_bc81_25f06342df0b_MD0003_00 This 4-week-old, preterm infant has had prolonged oxygen and is therefore at risk for developing bronchopulmonary dysplasia (BPD), or chronic lung disease of prematurity. Before widespread use of antenatal steroids and neonatal surfactant, "old" BPD was characterized by fibrotic, scarred, and hyperinflated lungs due to chronic ventilator injury. Because noninvasive ventilation has become more common, "new" BPD is seen more frequently and is associated with the arrest of pulmonary development in premature neonates. "New" BPD is characterized by pulmonary dysplasia with pathologic findings of a reduced number and septation of alveoli and an increased distance between alveoli and pulmonary capillaries. BPD is diagnosed when a premature infant requires ≥28 days of supplemental oxygen therapy. Signs of respiratory distress (eg, tachypnea, retractions) are often present, as seen in this patient. Management includes nutritional support, fluid restriction, and avoidance of mechanical lung damage. Over time, infants with BPD develop new alveoli, and results of pulmonary function testing can normalize. (Choice A) Pulmonary interstitial emphysema (PIE) is caused by air dissecting from the alveoli into the interstitial space. Like other air leak syndromes (eg, pneumothorax), the greatest risk for PIE occurs within days of birth, when lung compliance is decreased and high airway pressures are needed to support breathing. This infant has been on only nasal cannula for several weeks, making PIE unlikely. (Choice B) Cystic dilation of the bronchial wall with mucus plugging (ie, bronchiectasis) can be seen in "old" BPD, which is inconsistent with only a 4-day history of intubation. Patients with cystic fibrosis can also develop bronchiectasis, but in addition to respiratory distress, delayed passage of meconium and failure to thrive are typical. (Choice C) Protein-losing enteropathy can be caused by gastrointestinal inflammation or lymphatic obstruction (eg, intestinal lymphangiectasia). Patients typically have diarrhea and failure to thrive, neither of which is seen in this patient. Moreover, this condition is not associated with prematurity or chronic oxygen therapy. (Choice E) Refeeding syndrome (eg, hypophosphatemia, congestive heart failure) can be seen when nutrition is reintroduced following prolonged malnutrition. Although this patient has just started enteral feeds, he has been receiving intravenous nutrition with appropriate weight gain, eliminating the risk for this condition. Educational objective: Bronchopulmonary dysplasia is a chronic complication of prematurity caused by the arrest of pulmonary development and characterized by a prolonged oxygen requirement. Histologic findings include a decreased number and septation of alveoli. References: Bronchopulmonary dysplasia and pulmonary outcomes of prematurity. (http://www.ncbi.nlm.nih.gov/pubmed/30986315)

A 4-Week-Old Boy Is Being Evaluated in the Neonatal Intensive