USMLE (United States Medical Licensing Examination): Step 1: Basic sciences assessment Practice Exam 07
Practice exam for USMLE (United States Medical Licensing Examination): Step 1: Basic sciences assessment.
Question 1
MEDIUMA 67-year-old man presents to the clinic with progressive shortness of breath and chronic cough for 5 years. He has smoked 1.5 packs of cigarettes daily for 45 years. He uses an albuterol inhaler as needed. Temperature is 36.9°C (98.4°F), blood pressure is 134/78 mm Hg, pulse is 86/min, and respiratory rate is 18/min. Physical examination shows prolonged expiration and decreased breath sounds bilaterally. Pulmonary function testing shows an obstructive pattern with increased total lung capacity and residual volume. Which of the following best explains the increased total lung capacity in this patient?
This patient has COPD with emphysema (smoking history, hyperinflation with increased TLC/RV). Emphysema increases lung compliance and decreases elastic recoil due to destruction of alveolar septa, leading to air trapping and increased TLC. Increased airway resistance (eg, chronic bronchitis/asthma) contributes to obstruction but does not primarily explain increased TLC. Increased pulmonary capillary hydrostatic pressure suggests cardiogenic pulmonary edema (restrictive physiology).
Question 1 of 100
Community
Loading ranked answers and discussion...