A full-term infant girl is born by spontaneous vaginal delivery to a G2P1 mother. Upon physical examination, a bluish tinge to the skin and lips is immediately noted as well as marked tachypnea. Auscultation of the heart reveals a murmur. She is taken to have an echocardiogram which shows atrial septal defect (ASD), ventricular septal defect (VSD), and right ventricular hypoplasia.
The patient is given alprostadil to stabilize her condition while surgery is scheduled. Which of the following is the most likely condition affecting this patient?
D) Tricuspid atresia
In tricuspid atresia, the tricuspid valve is absent. This removes the connection between the right atrium and right ventricle, causing the right ventricle to be hypoplastic due to underuse. An ASD and VSD are thus present to allow adequate blood flow between the right and left atria and the left and right ventricle, respectively. Other abnormalities such as ventricular septal defect, pulmonary stenosis, and transposition of the great arteries may also be present.
Answer choice A: Tetralogy of Fallot, is incorrect. Although Tetralogy of Fallot would have a VSD, there would actually be right ventricular hypertrophy.
Answer choice B: Total anomalous pulmonary venous return (TAPVR) is incorrect. Although TAPVR might have an ASD, there would not be any tissue size adaptations.
Answer choice C: Transposition of the great vessels, is incorrect. Transposition of the great vessels by definition only has a switch in positions of the aorta and pulmonary arteries.
Answer choice E: Truncus arteriosus, is incorrect. Truncus arteriosus presents as a single large vessel where the pulmonary trunk and aorta should have been. There is always an associated ventricular septal defect. Multiple subtypes of truncus arteriosus exist and relate to the branching pattern of the pulmonary arteries. Because the aorta contains combined ouitput from the left and right ventricles, this results in cyanosis.
Key Learning Point
There are five cyanotic heart diseases which are important to remember. These conditions are characterized by right-to-left shunts where deoxygenated blood is put into the systemic circulation with subsequent early cyanosis. A helpful memory device is the five-finger method where each condition is assigned to a certain number of fingers on a hand.
- One finger up - Truncus Arteriosus, referring to the single common vessel that develops from the lack of division into the pulmonary trunk and aorta.
- Two fingers up and crossed - Transposition of the Great Vessels, referring to the transposition between the aorta and pulmonary trunk, causing the aorta to come off of the right ventricle and the pulmonary trunk to come off the left ventricle.
- Three fingers up - Tricuspid Atresia, referring to the three valves of the tricuspid valve. The valve itself is absent in this condition, leading to right ventricular hypoplasia and the necessity for an ASD and VSD.
- Four fingers up - Tetralogy of Fallot, referring to the four abnormalities associated with this condition. These abnormalities are: pulmonary stenosis, right ventricular hypertrophy, overriding aorta, and ventricular septal defect.
- Five fingers up - TAPVR, referring to the five words in the name. This condition presents with the pulmonary veins draining into the systemic circulation. A shunt between the atria is also necessary to maintain proper blood flow.
