This patient's presentation of exercise intolerance, lower extremity cyanosis, and a widened pulse pressure is consistent with a diagnosis of patent ductus arteriosus (PDA). A continuous, machine-like murmur loudest at the left infraclavicular area is associated with PDA.
It is important to be able to differentiate PDA from coarctation of the aorta based on examination and history findings. PDA is characterized by lower extremity cyanosis, while coarctation of the aorta manifests with lower extremity exercise intolerance without cyanosis. There is shunting of the blood from the right to left in PDA; in cases of a severe preductal coarctation, a persistent PDA may be necessary to maintain sufficient blood flow (albeit partially venous) to the lower extremities.
McConnell et al. discuss differentiating pathologic versus innocent/benign murmurs in children. The most common causes of pathologic murmurs in children include ASD, VSD, PDA, and abnormalities of the pulmonary/aortic outflow tracts. Murmurs that are louder than grade 3 or a diastolic murmur that increases in intensity with standing are concerning for an underlying pathologic process, necessitating referral to a cardiologist.
Fadel et al. discuss the hemodynamic findings associated with PDA in adults. Minor right-to-left shunting from a small PDA typically has no significant hemodynamic effects. However, a larger PDA with significant left-to-right shunting can lead to left-sided volume overload, heart failure, pulmonary hypertension, and Eisenmenger's syndrome. Although often diagnosed in childhood, some cases of PDA may first be discovered in adulthood when signs or symptoms of the disease become more noticeable.
Illustration A shows the anatomical defect associated with PDA. Illustration B summarizes phonograms of some of the most common systolic murmurs.
Answer 1: A mid-systolic murmur loudest at the right second intercostal space, with radiation to the right neck is suggestive of aortic stenosis.
Answer 2: Mitral stenosis is associated with a holodiastolic murmur loudest at the apex accompanied by an opening snap following the S2 heart sound.
Answer 3: A systolic murmur with weak femoral pulses and decreased lower extremity blood pressures is suggestive of coarctation of the aorta. Coarctation of the aorta presents with exercise intolerance WITHOUT any lower extremity cyanosis.
Answer 5: A continuous murmur at the right supraclavicular area that is obliterated by pressure on the ipsilateral internal jugular vein is suggestive of a venous hum - a common innocent murmur.
McConnell ME, Adkins SB 3rd, Hannon DW. Heart murmurs in pediatric patients: when do you refer? Am Fam Physician. 1999 Aug;60(2):558-65.
PMID:10465230 (Link to Abstract)
Fadel BM, Mohty D, Husain A, Dahdouh Z, Al-Admawi M, Pergola V, Di Salvo G. The Various Hemodynamic Profiles of the Patent Ductus Arteriosus in Adults. Echocardiography. 2015 Apr 12.
PMID:25865358 (Link to Abstract)