A 58-year-old man comes to the office due to increased dyspnea on exertion and wheezing over the last 2 months. He has never had these symptoms before and says they "make it harder to sleep." There is no family history of asthma.
On physical examination, the lungs have good air movement with scattered wheezes and no crackles. No edema is present at the ankles.
The results of pulmonary function testing are as follows:
Which of the following additional findings would most strongly support the diagnosis of asthma as opposed to chronic obstructive lung disease in this patient?

Question

A 58-year-old man comes to the office due to increased dyspnea on exertion and wheezing over the last 2 months.  He has never had these symptoms before and says they "make it harder to sleep."  There is no family history of asthma.
On physical examination, the lungs have good air movement with scattered wheezes and no crackles.  No edema is present at the ankles.
The results of pulmonary function testing are as follows:
 Which of the following additional findings would most strongly support the diagnosis of asthma as opposed to chronic obstructive lung disease in this patient?

Quizplus · Accepted Answer

11ec193a_98e5_b0bb_853d_f51470ba57d5_MD0002_00 The most effective way of differentiating asthma and chronic obstructive pulmonary disease (COPD) is spirometry before and after administration of a bronchodilator (usually albuterol). In patients with asthma, there is a significant reversal in airway obstruction (>12% increase in FEV1, absolute increase in FEV1 of >200 mL) in response to bronchodilator therapy. Patients with COPD may have partial reversibility, but near-complete restoration of normal airflow after bronchodilator administration effectively rules out COPD. (Choice A) Residual volume, the volume of air remaining in the lungs following exhalation, is characteristically increased in COPD due to obstructive air trapping. However, it can also increase during periods of active asthma or in severe asthma and therefore cannot reliably differentiate COPD from asthma. (Choice C) Smoking is strongly associated with COPD; however, up to 20% of patients with COPD have no smoking history. Smoking also increases the risk of asthma. (Choice D) Diffusion capacity of the lung for carbon monoxide is normal or increased in asthma. It is decreased in late-stage COPD due to emphysematous airway destruction and impaired gas exchange. However, it is often normal in early COPD or chronic bronchitis-predominant COPD and is therefore unreliable in differentiating COPD and asthma. (Choice E) Patients with asthma or COPD can have a chronic productive cough; its presence does not readily differentiate between the disorders. Educational objective: The degree of reversibility of airway obstruction in response to bronchodilators best distinguishes asthma from chronic obstructive pulmonary disease. __________ References: Making the diagnosis of asthma. (http://www.ncbi.nlm.nih.gov/pubmed/18426612) Diagnosis of asthma in adults. (http://www.ncbi.nlm.nih.gov/pubmed/19770241)

A 58-Year-Old Man Comes to the Office Due to Increased