Review Question - QID 217313

This neonate who presents with episodes of cyanosis and agitation after feeding (“Tet” spells), tachypnea, a harsh systolic ejection murmur at the left upper sternal border, diaphoresis, and central cyanosis (blue-colored trunk/central body) most likely has Tetralogy of Fallot.

Tetralogy of Fallot is a cyanotic heart disease that is characterized by right ventricular outflow tract obstruction, right ventricular hypertrophy, ventricular septal defect, and an overriding aorta. Tetralogy of Fallot is the most common cyanotic congenital heart disease and presents with tachypnea, diaphoresis, central cyanosis (extent of cyanosis is dependent on the severity of right ventricular outflow tract obstruction), a harsh systolic ejection murmur at the left upper sternal border, and “Tet” spells (intermittent hypercyanotic episodes commonly occurring after feeding or during crying). In older children, “Tet” spells often cause the child to squat, which increases systemic vascular resistance, decreasing the right-to-left shunt and improving pulmonary circulation. The diagnosis can be made prenatally using fetal echocardiography. In severely cyanotic neonates, intravenous prostaglandins are used to maintain a patent ductus arteriosus and pulmonary circulation pending surgery. “Tet” spells are managed by placing the child in a knee-chest position and administering oxygen. Definitive treatment is surgical repair.

Apitz et al. reviewed the diagnosis and management of Tetralogy of Fallot. They note that prior to the availability of surgical repair, many infants with this condition died in the first few years of life. They recommend surgical repair as almost all infants with Tetralogy of Fallot who undergo operative fixation are able to survive into adulthood.

Incorrect Answers:
Answer 1: Isolated atrial septal defect (ASD) is a common acyanotic congenital heart defect characterized by persistent communication between the right and left atria. Because the shunting is left-to-right, patients are typically acyanotic. Most ASDs are small and do not cause any symptoms in childhood whereas larger ASDs can cause recurrent pulmonary infections, failure to thrive, and signs of heart failure (fatigue, dyspnea, poor feeding, poor weight gain). The classic murmur of ASD is fixed splitting of S2.

Answer 2: Isolated ventricular septal defect (VSD) is a common acyanotic congenital heart defect characterized by persistent communication between the right and left ventricles. Because the shunting is left-to-right, patients are typically acyanotic. Most VSDs are small and asymptomatic. Larger VSDs present within the first 3-4 weeks of life with signs of heart failure. VSD murmurs are harsh, holosystolic murmurs best heard at the left lower sternal border.

Answer 3: Patent ductus arteriosus (PDA) is a common acyanotic congenital heart defect characterized by failure of the ductus arteriosus to close, resulting in persistent connection between the pulmonary arteries and aorta. Because shunting is left-to-right, patients are typically acyanotic. PDA presents with a continuous, “machine-like” murmur and signs of heart failure within the first few weeks of life. Physiological constriction of the ductus arteriosus is still occurring in this neonate.

Answer 5: Tricuspid valve atresia is the second most common cyanotic congenital heart defect characterized by the absence of a direct connection between the right atrium and ventricle. Survival is only possible with concurrent ASD and VSD to link the pulmonary circulation to the systemic circulation. Patients present with tachypnea, diaphoresis, and central cyanosis. Tricuspid atresia causes a systolic murmur best heard over the left lower sternal border and would not cause “Tet” spells.

Bullet Summary:
Tetralogy of Fallot is a congenital cyanotic heart disease that presents with tachypnea, diaphoresis, and central cyanosis, along with a harsh systolic murmur at the left upper sternal border and Tet spells.