Why does PDA increase a child's incidences of respiratory infections?
a. PDA reduces blood flow to the lungs, resulting in reduced delivery of white blood cells to lung tissue to fight infection.
b. PDA increases blood pressure in the lungs, which reduces movement of lymph. Reduced lymph movement results in lower flow through lymph nodes and increased infection.
c. PDA causes pulmonary hypertension and congestion. This results in fluid leakage into the lungs, and the persistent fluid provides an environment conducive to bacterial growth, thus increasing the incidences of respiratory infections.
d. PDA interferes with proper thymus development, resulting in reduced levels of B-cells.