A 54-year-old man is being evaluated for shortness of breath and cough. His medical problems include rheumatoid arthritis, hypertension, and a history of deep vein thrombosis and pulmonary embolism. He takes multiple medications and has smoked for 30 years. BMI is 34 kg/m². Examination shows dullness to percussion over the right lower lobe. Breath sounds are increased, especially during expiration, over the right lung base compared to the left. Cardiac examination shows regular rate and rhythm with normal S1 and S2. There is no murmur. Moderate peripheral edema is present. Which of the following is the most likely cause of his shortness of breath and lung examination findings?

Question

Quizplus · Accepted Answer

11ec25c8_d136_d027_bc81_3333868b3320_MD0003_00 This patient with shortness of breath, cough, and dullness to percussion with increased breath sounds over the right lower lung field likely has lobar pneumonia causing focal lung consolidation. A normal lung is resonant to percussion, and auscultation at the periphery demonstrates vesicular breath sounds that consist of a quiet inspiratory phase and an almost inaudible expiratory phase. When a portion of the lung is consolidated (eg, lobar pneumonia), the density of tissue/fluid increases and dullness to percussion is detected. In addition, sound conducts more rapidly and efficiently through consolidated lung, resulting in increased intensity of breath sounds and a more prominent expiratory component. More rapid and efficient sound conduction also results in increased tactile fremitus (vibration generated by air movement in the lungs) as well as egophony (sounds like the letter "A" when the patient says the letter "E") in areas of lung consolidation. Crackles are also often heard. (Choice B) The lungs are bilaterally hyperresonant to percussion in emphysema, and the intensity of breath sounds is decreased. Wheezing is commonly present as well. (Choice C) Patients with interstitial lung disease have lungs that are resonant to percussion and breath sounds of normal or decreased intensity. Fine crackles are heard at the end of inspiration. (Choice D) Mucus plugging decreases airflow in the affected part of the bronchial tree resulting in collapse of the downstream lung parenchyma (atelectasis). Breath sounds will be absent in the affected area. (Choice E) Unlike lung consolidation, pleural effusions are characterized by decreased breath sounds and decreased tactile fremitus as the fluid in the thoracic cavity acts to insulate sound and vibration originating in the lungs. As with lung consolidation, dullness to percussion is present due to increased tissue/fluid density compared to normal air-filled lung tissue. (Choice F) Air in the thoracic cavity also acts to insulate sounds originating from the lung; therefore, pneumothorax is characterized by decreased breath sounds and decreased tactile fremitus. Hyperresonance to percussion occurs due to a relatively lower density of air alone compared to normal air-filled lung tissue. Educational objective: Lung consolidation (eg, lobar pneumonia) presents with dullness to percussion, increased intensity of breath sounds, and increased tactile fremitus.

A 54-Year-Old Man Is Being Evaluated for Shortness of Breath