Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.
A 56-year-old woman is evaluated during an appointment to establish care. She has a developmental delay, and she is known to have pulmonary hypertension due to a congenital cardiac condition. There is no history of cardiac surgery. She is on low-dose aspirin and thyroid replacement therapy.
On physical examination, blood pressure is 110/70 mm Hg, pulse rate is 68/min and regular, and respiration rate is 18/min. BMI is 32. The central venous pressure is elevated with a prominent a wave. The apical impulse is normal. There is a prominent parasternal impulse at the left sternal border. The S1 is normal; the S2 is loud. There is a grade 1/6 holosystolic murmur at the left lower sternal border. The toes demonstrate cyanosis and digital clubbing; her hands appear normal. The remainder of the physical examination is unremarkable.
Which of the following is the most likely cause of this patient’s pulmonary hypertension?
A. Atrial septal defect
B. Patent ductus arteriosus
C. Tetralogy of Fallot
D. Ventricular septal defect
MKSAP Answer and Critique
The correct answer is B. Patent ductus arteriosus.
The patient has a patent ductus arteriosus (PDA) with secondary pulmonary hypertension (Eisenmenger syndrome). Clinical features of an Eisenmenger PDA include clubbing and oxygen desaturation affecting the lower body. This differential cyanosis and clubbing are caused by desaturated blood reaching the lower part of the body preferentially.
Pulmonary hypertension occurs infrequently in patients with unrepaired atrial septal defects owing to the relatively small shunt size. Clinical features of unrepaired atrial septal defect with pulmonary hypertension include cyanosis and clubbing that affects the hands and feet equally. The clinical findings are otherwise similar to findings in patients with idiopathic pulmonary arterial hypertension, with a parasternal lift and increased S2.
Unrepaired tetralogy of Fallot consists of right ventricular outflow tract obstruction and a large ventricular septal defect with secondary features of right ventricular hypertrophy and aortic override. Clinical features include cyanosis and clubbing that affect the hands and feet equally and a loud early systolic murmur heard at the left sternal border related to the right ventricular outflow tract obstruction. The pulmonic component of the S2 is generally soft or absent depending on the degree of pulmonary valve stenosis. Right ventricular hypertension but not pulmonary hypertension is present; the pulmonary vasculature is protected by the presence of pulmonary valve stenosis.
A ventricular septal defect can cause pulmonary hypertension if it remains open beyond age 2 years. Clinical features include cyanosis and clubbing that affect the hands and feet equally, a parasternal lift, and increased S2. Differential clubbing and cyanosis would not occur in a patient with pulmonary hypertension related to a ventricular septal defect.
Key Point
- A patent ductus arteriosus with Eisenmenger syndrome is characterized by differential cyanosis and clubbing affecting the lower body.
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