A Case of Delayed Presentation of Transposition of the Great Arteries

INTRO: Transposition of the great arteries (TGA) is a rare cyanotic congenital heart defect (CHD) typically presenting the first month of life. Late presentations may occur in patients with associated cardiac anomalies allowing for mixing of oxygenated and deoxygenated blood, such as ventral septal defects or large atrial septal defects (ASD). We present a case of a late-presenting TGA with no ventral septal defect, and only small ASD and patent ductus arteriosus (PDA). CASE: A 2-month-old female infant presented to a rural emergency department with respiratory distress for 1 day. On arrival, she was cyanotic with only mild improvement in oxygen saturations on 15-L non-rebreather. Grade IV/VI murmur was noted, and prostaglandin E was started. She required intubation after becoming apneic and was transported to the local pediatric referral hospital. There, echocardiography showed dextro-type TGA, with 8-mm ASD with minimal gradient, small PDA with left to right flow, and ventral septal bowing. She underwent balloon septostomy and then atrial switch, which was well tolerated. DISCUSSION: Our case is unique because of the patient's late presentation and prior lack of symptoms, given minimal levels of blood mixing though small ASD and PDA. Most TGA cases are now identified during prenatal ultrasound or with CHD screening pulse oximetry before discharge from the newborn nursery; however rare cases of late-presenting TGA may exist. CONCLUSION: Practitioners must maintain consideration of TGA, even after the newborn period, despite advances in newborn CHD screening in infants who present with new-onset respiratory distress without infection.