A Newborn With Respiratory Distress

A newborn term female presents with respiratory distress soon after delivery.

Prenatal history:

· 21-year-old gravida 5 para 3 mother
· Estimated gestational age: 39 5/7 weeks
· Blood type O+, hepatitis B surface antigen negative, rubella immune, group B Streptococcus (GBS) screen positive
· Spontaneous rupture of membranes at 5 hours prior to delivery and clear amniotic fluid
· Mother received one dose of ampicillin 4 hours prior to delivery for GBS prophylaxis

Birth history:
· The infant was delivered from vertex presentation by spontaneous vaginal delivery. A pediatric team was not present at the delivery because there were no risk factors. Apgar scores were 9 at 1 and 5 minutes.

Presentation:
· At approximately 10 minutes after birth, the infant’s heart rate was 190 beats/min, and she exhibited signs of respiratory distress, including grunting and retractions. The pediatric team was called and after further assessment, the infant was admitted to the intensive care nursery. Birthweight was 2,819 g.

Case Progression:
·   Vital Signs:
o Heart rate: 150 beats/min
o Respiratory rate: 40 breaths/min
o Blood pressure: 76/34 mm Hg
o Temperature: 98.6ºF (37ºC)
· Physical Examination:
o No dysmorphic features; intact palate; mild cephalhematoma; patent nares

o Lungs: Clear; equal breath sounds; intermittent, mild nasal flaring and subcostal retractions
o Cardiovascular Examination: Normal S1, S2; regular rhythm; no murmur; equal peripheral pulses
o Abdominal Examination: Soft; no masses; two-vessel umbilical cord
o Neurologic Examination: Appropriate
strength and tone
o Skin: No icterus, rashes, or lesions
Complete blood count, blood culture, and cerebrospinal fluid are obtained for evaluation of sepsis, and ampicillin and gentamicin are initiated. A chest radiograph CXR reveals opacification of the right lung. The infant is placed on nasal continuous positive airway pressure. At 3 hours after birth, she is transitioned to nasal cannula oxygen without difficulty, and by 1 day after birth, the infant is breathing comfortably in room air. A repeat chest radiograph at 1 day after birth reveals persistent, complete right lung opacification.

Differential Diagnosis:
Term infant presenting with mild respiratory distress at birth and persistent right lung opacification on chest radiograph.
· Blood aspiration
· Bronchopulmonary sequestration
· Congenital cystic adenomatoid malformation
· Congenital diaphragmatic hernia
· Group B streptococcal pneumonia
· Mucus plug in right mainstem bronchus
· Paralyzed right hemidiaphragm
· Respiratory distress syndrome
· Scimitar syndrome
· Tumor in the right lung

Actual Diagnosis:
Scimitar Syndrome
The chest radiograph continued to demonstrate right lung opacification at 3 days after birth. Fluoroscopy of the diaphragm was performed to rule out phrenic nerve dysfunction and hemidiaphragmatic paralysis. Although the right hemidiaphragm movement was dampened, neither paradoxic movement nor paralysis was observed. Computed tomography (CT) (with contrast) of the chest revealed what appeared to be an enhancing right lower lobe mass in the lung with a draining vein into the inferior vena cava. This sequestration received its arterial supply from the aorta. Subsequent echocardiography revealed a small right pulmonary artery and an anomalous vein from the right lower lobe that drained into the inferior vena cava, a so-called “scimitar vein,” a finding consistent with scimitar syndrome.
Cardiac-gated CT confirmed these findings, delineating a hypoplastic right pulmonary artery, right lower lobe sequestration of the lung with an arterial supply from an infradiaphragmatic aortic branch, and venous drainage through the right portal vein. Three aortopulmonary collaterals supplied the right middle and lower lobes; a small native right pulmonary artery supplied the right upper lobe.
Two aberrant pulmonary veins drained the right lung, but did not empty into the left atrium. Rather, most of the right lung drained into a “scimitar-like” anomalous pulmonary vein into the inferior vena cava at or just below the diaphragm.
Although not a consistent finding in scimitar syndrome, this patient also had abnormalities in left pulmonary venous drainage. Most of the left lung drained into a single, narrow channel into the left atrium. A portion of the medial left lower lobe drained through an aberrant vein that crossed the midline into the right lower lobe and emptied into the inferior vena cava.
Several advanced imaging modalities are useful in diagnosing scimitar syndrome, including cardiac-gated magnetic resonance imaging MRI and CT angiography. Cardiac catheterization (Cath) not only can confirm the diagnosis, but it can be a form of treatment with coil embolization of the systemic feeding arteries. This may offer the best clinical outcome in symptomatic infants. The patient presented in this case underwent catheterization and coil embolization at 6 days after birth. Other treatment strategies include complete repair (reimplantation of the vein to the left atrium, ligation of systemic collaterals, and repair of associated cardiac defects) and right pneumonectomy.
(from http://neoreviews. aappublications.org)

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