Which signs indicate pneumonia?

• A. Cough with green, red, or rust-colored sputum and localized crackles
• B. Sudden chest pain with dyspnea and subcutaneous emphysema
• C. Fever and barking cough in a pediatric patient
• D. Coughing fits with a "whooping" sound and fever

Answer: (A)

Pneumonia shows up when the lung tissue becomes inflamed and filled with infectious exudate, leading to a localized area of consolidation. A productive cough with sputum that can be green, yellow, or rust-colored reflects this infectious drainage, and listening over the affected area often reveals localized crackles (rales) from the fluid-filled airways and collapsed, inflamed tissue. The combination of a productive cough with purulent or colored sputum and localized crackles is a classic clue that the infection is focused in a portion of the lung, which is typical of pneumonia and helps distinguish it from other respiratory conditions.

The other scenarios point to different problems: sudden chest pain with dyspnea and subcutaneous emphysema suggests air leaking into tissues (pneumothorax or pneumomediastinum) rather than consolidation. A fever with a barking cough in a child points to croup, an upper airway viral illness. Paroxysmal coughing with a whoop and fever describes pertussis, not focal pneumonia.