A client with a systemic infection from an infected leg wound tells the nurse, It's getting hard to ...

4. Acute respiratory distress syndrome.

Rationale:
Sepsis is the most common cause of acute respiratory distress syndrome. The client has a systemic infection, which is sepsis, and is complaining that it is getting hard to breathe. The nurse should suspect the client is developing acute respiratory distress. Deep vein thrombosis, anemia, or allergic response from antibiotic therapy may or may not be associated with a systemic infection from an infected leg wound and are not associated with the development of acute respiratory distress syndrome.