A 72-year-old man with COPD develops acute shortness of breath and presents to the hospital. He appears uncomfortable: blood pressure is 120/90 mm Hg, pulse 100/min, oxygen saturation 85% on room air. On examination of the chest, there is absent fremitus, absent breath sounds, and hyper resonant percussion of the right lung. The trachea is shifted to the left.For the above patient with abnormal pulmonary physical findings, select the most likely diagnosis.

**Core Concept**
The clinical presentation of absent fremitus, absent breath sounds, hyperresonant percussion, and tracheal deviation in a patient with COPD suggests a condition affecting the lung's structural integrity, leading to reduced lung volume and mediastinal shift.

**Why the Correct Answer is Right**
The patient's symptoms and signs are consistent with a pneumothorax, a condition where air enters the pleural space, causing the lung to collapse. The absent fremitus and breath sounds are due to the air-filled pleural space, which prevents sound transmission and lung expansion. The hyperresonant percussion is a result of the air-filled space, and the tracheal deviation to the left indicates mediastinal shift due to the increased pressure in the right thoracic cavity. In COPD patients, bullae formation can increase the risk of pneumothorax.

**Why Each Wrong Option is Incorrect**
**Option A:** Pneumonia would typically present with increased lung markings, consolidation, and possibly a pleural rub, which is not seen in this patient.

**Option B:** Pulmonary edema would present with bilateral lung findings, such as crackles and increased lung markings, which is not consistent with the patient's unilateral findings.

**Option C:** Pulmonary embolism would present with sudden onset shortness of breath, tachycardia, and possibly a pleuritic chest pain, but the physical examination would not show absent breath sounds and hyperresonant percussion.

**Option D:** Pleural effusion would present with increased lung markings, dullness to percussion, and possibly a pleural rub, which is not seen in this patient.

**Clinical Pearl / High-Yield Fact**
A pneumothorax can be life-threatening and requires prompt diagnosis and treatment. The patient's COPD history and acute presentation make it essential to consider this diagnosis and perform an immediate chest X-ray.

**Correct Answer:** C. Pneumothorax

✓ Correct Answer: B. complete pneumothorax