I am going to answer the sample USMLE Step 1 Questions with Explanation. These questions are available at USMLE.org
A 39-year-old man comes to the physician because of a 6-month history of progressive shortness of breath. He has had a cough productive of white sputum for 2 years. He smoked 1 pack of cigarettes daily for 16 years but quit 10 years ago. He is in mild respiratory distress with pursed lips and a barrel chest; he is using the accessory muscles of respiration. Breath sounds are distant and crackles are present in the lower lung fields bilaterally. Pulmonary function tests show a decreased FEV1:FVC ratio, increased residual volume, and decreased diffusion capacity. An x-ray of the chest shows hyperinflation and hypertranslucency of the lower lobes of both lungs.
Which of the following is the most likely diagnosis?
(A) Asthma
(B) Bronchiectasis
(C) Chronic pulmonary fibrosis
(D) Cystic fibrosis
(E) Emphysema
Copyright © 1996-2021 Federation of State Medical Boards (FSMB) and National Board of Medical Examiners (NBME). All rights reserved. The United States Medical Licensing Examination® (USMLE®) is a joint program of the FSMB and NBME.
Answer
Progressive shortness of breath, chronic productive cough, history of smoking, barrel chest, and use of accessory muscles are classic signs of air trapping in emphysema. Distant breath sounds and crackles in the lower lung fields are also consistent with emphysema. Pulmonary function tests suggest obstructive lung disease. Hyperinflation and hypertranslucency of the lower lobes are classic radiographic signs of emphysema, as these indicate overexpanded and less dense lung tissue.
The correct answer is E
More Repeated USMLE Questions Step 1
Check this Review Book for Step 1