A 70-year-old man comes to the office with a 2-year history of progressive shortness of breath and productive cough. The patient describes frequent episodes of bronchitis treated with oral antibiotics. He has smoked a pack of cigarettes a day for the past 40 years. Breath sounds are decreased throughout the lung fields bilaterally.
Which of the following results is likely to be seen on pulmonary function testing?
FEV1 = forced expiratory volume in 1 second; FVC = forced vital capacity; DLCO = diffusing capacity for carbon monoxide.

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Quizplus · Accepted Answer

11ec193a_98e7_fab2_853d_bf46fc891df6_MD0002_00 This patient is a chronic smoker and has dyspnea and recurrent bronchitis, which is highly suggestive of chronic obstructive pulmonary disease (COPD). The diagnosis of COPD can be confirmed with the use of spirometry demonstrating airflow obstruction (forced expiratory volume in 1 second [FEV1] / forced vital capacity [FVC] ratio <0.7). The Global Initiative for COPD describes chronic bronchitis, emphysema, and asthma as an overlap of diseases resulting in airflow obstruction in which only patients with some component of asthma show significant reversibility of airflow limitation with bronchodilators (>12% increase in FEV1 and a >200 mL increase in FVC). Patients with COPD may show an incomplete response to bronchodilators (<12% increase in FEV1) in early disease, but the magnitude is smaller compared to those with asthma. Diffusing capacity for carbon monoxide (DLCO) is usually not reduced in asthma as lung parenchyma remains intact. Reduced DLCO in patients with airflow obstruction suggests the presence of emphysematous changes consistent with COPD. (Choices A and C) A positive bronchodilator response with normal DLCO and FVC is suggestive of asthma. FEV1 may be reduced or spirometry may be completely normal and still demonstrate a bronchodilator response. (Choice B) Normal spirometry with isolated reduction in DLCO may be seen in pulmonary vascular diseases (eg, primary pulmonary hypertension). (Choice E) The FEV1/FVC ratio remains normal in interstitial lung disease due to a comparable reduction in both FEV1 and FVC. DLCO is reduced. Educational objective: Irreversible airflow limitation in a chronic smoker with progressive dyspnea and chronic cough suggests chronic obstructive pulmonary disease. Reduced diffusing capacity for carbon monoxide signifies emphysema. __________ References: Diagnosis of chronic obstructive pulmonary disease. (http://www.ncbi.nlm.nih.gov/pubmed/18649615) Differentiating COPD from asthma in clinical practice. (http://www.ncbi.nlm.nih.gov/pubmed/17895488) Differential assessment and management of asthma vs chronic obstructive pulmonary disease. (http://www.ncbi.nlm.nih.gov/pubmed/19295941)

A 70-Year-Old Man Comes to the Office with a 2-Year