During evaluation of a patient receiving pressure support ventilation, examination findings include dull percussion at the right base, decreased movement on the right, and a chest X-ray showing blunting of the right costophrenic angle. What is the most likely pulmonary problem?

• A. Pleural effusion
• B. Pneumonia
• C. Pulmonary edema
• D. Atelectasis

Answer: (A)

Fluid in the pleural space causes dullness to percussion at the base, reduced movement of the affected lung, and blunting of the costophrenic angle on chest X-ray. These signs together point to a pleural effusion, where the accumulating fluid limits expansion of the underlying lung and shows up as a widened, obscured CP angle on radiographs.

Pneumonia would typically present with localized signs of infection and a focal infiltrate on X-ray rather than a blunted CP angle. Pulmonary edema often shows diffuse interstitial or alveolar markings and sometimes cardiomegaly rather than a specific CP angle blunting. Atelectasis can cause decreased movement and dullness, but it usually accompanies signs of volume loss and elevated diaphragms rather than the classic CP angle blunting seen with effusion.