USMLE Answer 26

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26. The correct answer is C. The infant probably has esophageal atresia, which is typically caused by posterior deviation of the tracheoesophageal septum. Attempts at feeding cause fluid to spill into the trachea, and secondarily cause aspiration pneumonia. Emergent surgical correction is usually required.

Bronchogenic cysts (choice A) are centrally located cysts that are often asymptomatic and may be associated with cysts of other organs.

Congenital pulmonary cysts (choice B) are often multiple and located in the lung periphery without connection to the bronchi; they are vulnerable to infection and rupture complicated by pneumothorax and/or hemoptysis.

Pulmonary immaturity (choice D) produces progressive difficulty in breathing beginning in the first few hours of life.

Pulmonary sequestration (choice E) represents extrapulmonary lung tissue supplied by systemic blood vessels rather than by pulmonary arteries.