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A full-term neonate, the product of an uncomplicated pregnancy and delivery, presents with cyanosis after normal spontaneous vaginal delivery. There is no family history of intrauterine demise, congenital heart disease, or sudden unexplained death. There was no prenatal drug or toxin exposure. The infant’s mother tested negative for group B Streptococcus, cytomegalovirus, human immunodeficiency virus, and hepatitis B; she is immune to rubella.
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Pulse oximetry reveals upper and lower extremity saturation of 75% to 80% on room air. One hundred percent blow-by-oxygen does not affect systemic saturations. Heart rate is 135 bpm. Respiratory rate is 30 breaths/min. Upper and lower extremity blood pressures are normal and equivalent. Physical exam reveals a fully developed term infant without any dysmorphic features. The infant is breathing comfortably without any respiratory distress. Precordial impulse is normal by palpation. There is a harsh 2 to 3/6 systolic ejection type murmur at the left upper sternal border. Lung fields are clear. Radial and pedal pulses are normal and symmetric. There is no radial-femoral pulse delay.
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A 34-year-old female Russian immigrant is referred for cardiology evaluation with a history of a heart murmur since birth. She has no specific complaints, although she describes a vague history of shortness of breath and fatigue at peak exertion. She denies any cyanosis. She has never been hospitalized or had surgery. There is no family history of congenital heart disease or sudden unexpected death.
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Vital signs include the following: heart rate 76 bpm, respiratory rate 14 breaths/min, right arm blood pressure 111/68 mm Hg; right leg blood pressure 115/72 mm Hg, and oxygen saturation 99%. On physical exam, she is a thin, healthy-appearing female who is in no distress. Carotid artery pulses are normal without bruit. She has no jugular venous distension. Radial and femoral pulses are 2+ and symmetric; there is no radial-femoral pulse delay. Chest is symmetric without deformity. Subxiphoid cardiac impulse is pronounced. There are no palpable thrills. There is an early systolic ejection click at the left upper sternal border. A harsh 3/6 systolic ejection murmur that spills into early diastole is heard throughout the precordium, most prominently at the left upper sternal border; there are no diastolic murmurs. Lungs are clear without wheezes, rales, or rhonchi. Her abdomen is soft, nontender, and flat with no hepatosplenomegaly. Extremities are warm and well perfused with no clubbing or cyanosis. There is trace pedal edema.
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DIFFERENTIAL DIAGNOSIS
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The differential diagnosis of cyanosis in a term newborn includes many cardiac and noncardiac etiologies. Cyanosis that resolves or improves significantly with administration of supplemental oxygen suggests ...