A 7-week-old boy is evaluated for persistent hypoxia. He has been in the neonatal intensive care unit since birth. He was born at 29 weeks gestation due to placental abruption and weighed 1150 g (2.5 lb). Six hours after delivery, the patient developed tachypnea, grunting, and cyanosis; a chest x-ray revealed ground-glass opacities. Surfactant was administered and mechanical ventilation was initiated. He remained on mechanical ventilation for the first 3 weeks of life. Ever since ventilation was discontinued, the patient has remained hypoxic and continues to require oxygen administration by nasal cannula. Temperature is 36.7 C (98 F), pulse is 124/min, and respirations are 50/min. He is awake and alert. No rhinorrhea or pharyngeal erythema is found. S1 and S2 are normal; a 1/6 systolic murmur is present at the lower left sternal border. Scattered rhonchi and rales are present in both lungs. The abdomen is soft without organomegaly. There is no extremity edema. Chest radiograph appears hazy bilaterally and demonstrates slightly decreased lung volumes. What is the most likely diagnosis for this patient's current presentation?

Question

A 7-week-old boy is evaluated for persistent hypoxia.  He has been in the neonatal intensive care unit since birth.  He was born at 29 weeks gestation due to placental abruption and weighed 1150 g (2.5 lb).  Six hours after delivery, the patient developed tachypnea, grunting, and cyanosis; a chest x-ray revealed ground-glass opacities.  Surfactant was administered and mechanical ventilation was initiated.  He remained on mechanical ventilation for the first 3 weeks of life.  Ever since ventilation was discontinued, the patient has remained hypoxic and continues to require oxygen administration by nasal cannula.  Temperature is 36.7 C (98 F), pulse is 124/min, and respirations are 50/min.  He is awake and alert.  No rhinorrhea or pharyngeal erythema is found.  S1 and S2 are normal; a 1/6 systolic murmur is present at the lower left sternal border.  Scattered rhonchi and rales are present in both lungs.  The abdomen is soft without organomegaly.  There is no extremity edema.  Chest radiograph appears hazy bilaterally and demonstrates slightly decreased lung volumes.  What is the most likely diagnosis for this patient's current presentation?

Quizplus · Accepted Answer

This premature, low-birth-weight infant initially developed respiratory distress syndrome (tachypnea, grunting, ground-glass opacities on chest radiograph) requiring surfactant therapy and mechanical ventilation. He now has a persistent oxygen requirement with tachypnea, rhonchi, and radiographic findings of haziness and decreased lung volumes. This presentation is consistent with bronchopulmonary dysplasia (BPD, chronic lung disease of the neonate), which results from repeated insult to the neonatal lung from factors such as mechanical ventilation, prolonged oxygen exposure, and inflammation. Risk factors for BPD include prematurity, low birth weight (<2,500 g), respiratory distress syndrome, and mechanical ventilation. Surfactant therapy does not prevent BPD development but may reduce mortality from it. Most patients with BPD improve over 2-4 months; some develop pulmonary arterial hypertension. (Choice A) Bronchiectasis is a result of airway remodeling and thickening due to chronic inflammation. In children, it is generally associated with cystic fibrosis (due to viscous secretions causing recurrent infection). It is not linked to prematurity or respiratory distress syndrome. (Choice C) Congenital heart disease with right-to-left shunting can present with respiratory distress, rales, and hypoxemia. However, this patient's soft 1/6 murmur is likely a flow murmur and is not consistent with ventricular septal defect (louder and harsher) or patent ductus arteriosus (machine-like). In addition, these conditions would have progressively worsened before 7 weeks of life. (Choice D) Meconium aspiration syndrome can present with respiratory distress at birth. However, it typically occurs in full-term infants and is unusual in a low-birth-weight, premature baby. It usually resolves within the first week of life. (Choice E) Neonatal pneumonia could be associated with mechanical ventilation and present with tachypnea and rales. However, without appropriate treatment there would have been further deterioration (eg, ventilation and oxygen requirements would increase by this point). (Choice F) Persistent pulmonary hypertension presents with tachypnea and hypoxia. It results when the neonatal pulmonary vascular resistance fails to decrease during the transition from fetal circulation. However, it is not associated with respiratory distress syndrome and is uncommon in premature infants. Educational objective: Bronchopulmonary dysplasia (chronic lung disease of the neonate), which causes a persistent oxygen requirement, is commonly seen in premature infants, especially in those requiring prolonged mechanical ventilation or oxygen supplementation. References: Pathogenesis and treatment of bronchopulmonary dysplasia. (http://www.ncbi.nlm.nih.gov/pubmed/21494147)

A 7-Week-Old Boy Is Evaluated for Persistent Hypoxia