Review Question - QID 101897

This patient's presentation is consistent with a patent ductus arteriosus (PDA). The 6th aortic arch gives rise to the ductus arteriosus as well as both the left and right pulmonary arteries.

Of note, the artery of arch 6 is obliterated during development, while the left side of arch 6 persists as the ductus arteriosus. Normally, the ductus arteriosus closes down soon after birth, resulting in the residual ligamentum arteriosum. Risk factors for development of PDA include prematurity and TORCH infection, among others. Indomethacin is utilized to close a PDA; while prostaglandin E2 (PGE2) can be given to maintain PDA patency in patients requiring persistence of the left-to-right shunt for oxygenation (tetralogy of Fallot and transposition of great vessels).

Incorrect Answers:
Answer 1: The 1st branchial cleft gives rise to the external auditory meatus.
Answer 2: The 4th branchial arch develops into the cricothyroid muscle as well as the majority of the muscles of the soft palate, thyroid cartilage, vagus nerve, superior laryngeal nerve.
Answer 3: The 4th branchial pouch yields the superior parathyroids.
Answer 5: The 6th branchial pouch does not exist, there are only 1-4 pouches.