A 53-year-old man comes to the office with a 2-year history of seasonal cough, episodic shortness of breath, and wheezing. Family history is significant for asthma in his mother. The patient uses hydrocortisone cream as needed for atopic dermatitis. He has a 34-pack-year smoking history and consumes alcohol occasionally. Physical examination shows diminished breath sounds and bilateral scattered expiratory wheezes. Office evaluation shows a decreased peak expiratory flow rate. Which of the following would be most helpful in differentiating asthma from chronic obstructive pulmonary disease in this patient?

Question

A 53-year-old man comes to the office with a 2-year history of seasonal cough, episodic shortness of breath, and wheezing.  Family history is significant for asthma in his mother.  The patient uses hydrocortisone cream as needed for atopic dermatitis.  He has a 34-pack-year smoking history and consumes alcohol occasionally.  Physical examination shows diminished breath sounds and bilateral scattered expiratory wheezes.  Office evaluation shows a decreased peak expiratory flow rate.  Which of the following would be most helpful in differentiating asthma from chronic obstructive pulmonary disease in this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d2a8_6165_bc81_fda7790656ab_MD0003_00 Asthma and chronic obstructive pulmonary disease (COPD) are common lower respiratory tract inflammatory diseases characterized by dyspnea, cough, wheezing, and airflow obstruction (eg, decreased peak expiratory flow rate). Asthma is an atopic disease with a strong genetic contribution and early life onset; COPD (chronic bronchitis or emphysema) is due primarily to tobacco use and presents later in life. In practice, asthma and COPD often overlap in age of onset and clinical manifestations. This patient has clinical features of both asthma (seasonality, episodic symptoms, eczema, family history) and COPD (middle age, heavy smoking). Asthma and COPD are fundamentally distinguished by the reversibility of airflow obstruction. Therefore, the best test for discriminating between them is spirometry before and after a short-acting bronchodilator (eg, albuterol): Patients with asthma show complete reversal (ie, post-bronchodilator FEV1/FVC ≥70%). Patients with COPD have only partial/weak reversibility. In advanced COPD, the airflow obstruction becomes fixed. Subjective symptom relief with a trial of albuterol is not correlated to the bronchodilator response on spirometry and therefore is a poor indicator of diagnosis (Choice F). Proper distinction is critical for the selection of long-term controller therapy: inhaled corticosteroids are preferred for asthma, whereas inhaled antimuscarinic therapy is preferred for COPD. (Choice A) In asthma, chest x-ray (CXR) is typically normal at baseline and may reveal hyperinflation during acute exacerbations. In COPD, CXR abnormalities are delayed until significant emphysema and air trapping develop. Although expiratory views may accentuate air trapping, findings are nonspecific and do not discriminate between asthma and COPD. Diffusion capacity of the lung for carbon monoxide can help distinguish between the forms of COPD (chronic bronchitis [near-normal] and emphysema [low]) but not between COPD and asthma (normal or high due to bronchial hyperemia). (Choice B) Inherited alpha-1 antitrypsin deficiency causes autoproteolysis of lung tissue, leading to panacinar emphysema and irreversible obstruction; testing should be considered in patients with premature-onset COPD disproportionate to smoking history. Deficiency does not usually cause asthma. (Choices C and E) Elevated serum IgE and sputum eosinophilia may be present in asthma, but findings are insensitive and nonspecific. Furthermore, some patients with COPD have sputum and peripheral blood eosinophilia. Serum IgE helps diagnose allergic bronchopulmonary aspergillosis, given a high index of suspicion (eg, refractory asthma, mucus plugging). Educational objective: Asthma and chronic obstructive pulmonary disease often have overlapping clinical presentations. They are distinguished by the reversibility of airflow obstruction on spirometry before and after a short-acting bronchodilator. References: Asthma (http://www.ncbi.nlm.nih.gov/pubmed/29273246)

A 53-Year-Old Man Comes to the Office with a 2-Year