A 63-year-old woman comes to the office due to slowly progressive dyspnea on exertion and cough productive of white-yellow sputum over the past several years. She has a history of rheumatoid arthritis and seasonal allergies. The patient has smoked a pack of cigarettes daily for 40 years. Blood pressure is 135/80 mm Hg and pulse is 76/min. Lung examination demonstrates mild, bilateral expiratory wheezes, and chest x-ray reveals hyperinflated lungs. Pulmonary function test results are as follows: Which of the following cells most likely played a major role in the pathogenesis of this patient's lung condition?

Question

A 63-year-old woman comes to the office due to slowly progressive dyspnea on exertion and cough productive of white-yellow sputum over the past several years.  She has a history of rheumatoid arthritis and seasonal allergies.  The patient has smoked a pack of cigarettes daily for 40 years.  Blood pressure is 135/80 mm Hg and pulse is 76/min.  Lung examination demonstrates mild, bilateral expiratory wheezes, and chest x-ray reveals hyperinflated lungs.  Pulmonary function test results are as follows:  Which of the following cells most likely played a major role in the pathogenesis of this patient's lung condition?

Quizplus · Accepted Answer

11ec160b_3b34_09e6_9249_a977becf1da2_MD0001_00 This patient with dyspnea, productive cough, and an obstructive pattern on pulmonary function testing-in the setting of a prolonged smoking history-likely has chronic obstructive pulmonary disease (COPD). COPD is characterized by chronic airway inflammation, which results in both parenchymal destruction (emphysema) and remodeling of the airways (chronic bronchitis). The primary cell lines that are increased in COPD are neutrophils, macrophages, and CD8⁺ T lymphocytes. These cells release enzymes and proteases, such as neutrophil elastase, that cause alveolar damage, reduced ciliary motion, and increased mucus secretion by goblet cells. In addition, the inflammatory cells show impaired ability to phagocytize bacterial pathogens, possibly contributing to increased risk of respiratory infections such as community-acquired pneumonia. (Choice A) The involvement of B lymphocytes in COPD pathogenesis is controversial; however, they do not appear to have a major role, and their increased numbers may actually be protective against bacterial colonization. (Choice B) Although CD4⁺ T lymphocytes are slightly increased in COPD, their numbers and pathologic role are much less significant than those of CD8⁺ T lymphocytes. However, CD4⁺ T lymphocytes have been implicated in asthma pathogenesis. (Choice C) Eosinophils play an important role in asthma but do not appear to have a major impact in COPD. Their increased presence in patients with COPD may indicate coexisting asthma. (Choice D) Patients with mast cell disorders can have flushing, abdominal discomfort, and respiratory symptoms such as dyspnea and wheezing due to bronchoconstriction. However, mast cells do not play an important role in the pathogenesis of COPD. Educational objective: Neutrophils, macrophages, and CD8⁺ T lymphocytes are the primary mediators of disease in chronic obstructive pulmonary disease. They secrete enzymes and proteases that cause and perpetuate both the alveolar destruction of emphysema and the mucus hypersecretion found in chronic bronchitis. __________ References: Cellular and molecular mechanisms in chronic obstructive pulmonary disease: an overview. (http://www.ncbi.nlm.nih.gov/pubmed/15298554) Inflammatory cells and chronic obstructive pulmonary disease. (http://www.ncbi.nlm.nih.gov/pubmed/17305517) Cellular and molecular mechanisms of chronic obstructive pulmonary disease. (http://www.ncbi.nlm.nih.gov/pubmed/24507838)

A 63-Year-Old Woman Comes to the Office Due to Slowly