RNC-NIC Congenital Anomalies 5 — Questions and Answers
Question 1: A neonate with suspected congenital heart disease has a pre-ductal SpO2 of 98% and a post-ductal SpO2 of 82%. This differential MOST suggests:
- Right-to-left shunting at the level of the ductus arteriosus, as seen in coarctation of the aorta or interrupted aortic arch (Correct answer)
- Left-to-right shunting causing pulmonary overcirculation
- Transient tachypnea of the newborn with resolving fluid
- Pulmonary hypertension with bidirectional ductal shunting
Correct answer: Right-to-left shunting at the level of the ductus arteriosus, as seen in coarctation of the aorta or interrupted aortic arch
A significant pre-ductal to post-ductal SpO2 gradient indicates right-to-left ductal shunting, meaning deoxygenated blood enters the descending aorta, seen in obstructive left-sided lesions.
Question 2: Which congenital heart defect is characteristically associated with a 'boot-shaped' heart on chest X-ray?
- Tetralogy of Fallot (Correct answer)
- Transposition of the great arteries
- Total anomalous pulmonary venous return
- Hypoplastic left heart syndrome
Correct answer: Tetralogy of Fallot
Tetralogy of Fallot produces a boot-shaped (coeur en sabot) cardiac silhouette due to right ventricular hypertrophy elevating the cardiac apex with a concave pulmonary artery segment.
Question 3: A neonate with Transposition of the Great Arteries (TGA) is deteriorating rapidly. Which medication is the MOST critical intervention before surgical correction?
- Prostaglandin E1 (alprostadil) to maintain ductal patency (Correct answer)
- Indomethacin to close the ductus arteriosus
- Dopamine to improve cardiac output
- Furosemide to reduce pulmonary congestion
Correct answer: Prostaglandin E1 (alprostadil) to maintain ductal patency
PGE1 keeps the ductus arteriosus open to allow mixing of oxygenated and deoxygenated blood, essential for survival in TGA until balloon atrial septostomy or surgery.
Question 4: A nurse notes that a neonate with Hypoplastic Left Heart Syndrome (HLHS) has increased SpO2 of 98% on room air. Why is this finding concerning?
- It suggests pulmonary overcirculation with decreased systemic flow, risking end-organ ischemia (Correct answer)
- It indicates the ductus arteriosus has closed prematurely
- It reflects improved cardiac output from spontaneous ventricular recovery
- It is a normal expected finding after prostaglandin therapy
Correct answer: It suggests pulmonary overcirculation with decreased systemic flow, risking end-organ ischemia
In HLHS, the right ventricle serves both circulations via the ductus; high SpO2 indicates blood is being preferentially directed to the lungs, stealing from systemic circulation.
Question 5: Which finding differentiates critical pulmonary stenosis from pulmonary atresia with intact ventricular septum in a cyanotic neonate?
- Critical pulmonary stenosis has a detectable anterograde flow across the pulmonary valve on echocardiography (Correct answer)
- Pulmonary atresia presents with a louder murmur at the left upper sternal border
- Critical pulmonary stenosis always has a normal chest X-ray
- Pulmonary atresia has better ductal-dependent flow to the lungs
Correct answer: Critical pulmonary stenosis has a detectable anterograde flow across the pulmonary valve on echocardiography
Critical pulmonary stenosis has a severely narrowed but patent pulmonary valve with some anterograde flow, distinguishing it from complete atresia where no forward flow exists.
Question 6: A NICU nurse is assessing a neonate with a suspected chromosomal anomaly. Which combination of findings is MOST consistent with Trisomy 18 (Edwards syndrome)?
- Clenched fists with overlapping fingers, rockerbottom feet, and micrognathia (Correct answer)
- Single palmar crease, upslanting palpebral fissures, and hypotonia
- Polydactyly, cleft lip, and holoprosencephaly
- Rocker-bottom feet, café-au-lait spots, and macrocephaly
Correct answer: Clenched fists with overlapping fingers, rockerbottom feet, and micrognathia
Trisomy 18 is characterized by clenched fists with the 2nd and 5th fingers overlapping the 3rd and 4th, rocker-bottom feet, micrognathia, and severe cardiac defects.
Question 7: A neonate with craniosynostosis involving only the sagittal suture. Which head shape deformity will the nurse observe?
- Scaphocephaly — an elongated, narrow skull (dolichocephaly) (Correct answer)
- Trigonocephaly — a triangular, keel-shaped forehead
- Plagiocephaly — asymmetric flattening of one side
- Brachycephaly — a short, wide, flat skull
Correct answer: Scaphocephaly — an elongated, narrow skull (dolichocephaly)
Premature fusion of the sagittal suture prevents lateral growth, forcing the skull to grow anteroposteriorly, producing scaphocephaly (long, narrow head).
RNC-NIC Congenital Anomalies 5
A neonate with suspected congenital heart disease has a pre-ductal SpO2 of 98% and a post-ductal SpO2 of 82%.
This differential MOST suggests: