A 68-year-old woman comes to the emergency department due to cough and shortness of breath. She has a history of chronic obstructive pulmonary disease and often coughs up clear sputum in the mornings. However, over the past 4 days, her cough has worsened significantly, and she now is expectorating thick, yellow sputum. The patient also feels "winded" when walking short distances or doing light house work. She is a former smoker with a 40-pack-year history. Temperature is 37.2 C (99 F), blood pressure is 130/70 mm Hg, pulse is 90/min, and respirations are 22/min. The patient is breathing with pursed lips. The expiration phase is prolonged. Lung auscultation reveals vesicular breath sounds with diffuse wheezes. Chest x-ray shows hyperinflated lungs with flattened diaphragm. There are no parenchymal opacities or pleural effusion. Respiratory infection with which of the following pathogens most likely triggered this patient's worsening symptoms?

Question

A 68-year-old woman comes to the emergency department due to cough and shortness of breath.  She has a history of chronic obstructive pulmonary disease and often coughs up clear sputum in the mornings.  However, over the past 4 days, her cough has worsened significantly, and she now is expectorating thick, yellow sputum.  The patient also feels "winded" when walking short distances or doing light house work.  She is a former smoker with a 40-pack-year history.  Temperature is 37.2 C (99 F), blood pressure is 130/70 mm Hg, pulse is 90/min, and respirations are 22/min.  The patient is breathing with pursed lips.  The expiration phase is prolonged.  Lung auscultation reveals vesicular breath sounds with diffuse wheezes.  Chest x-ray shows hyperinflated lungs with flattened diaphragm.  There are no parenchymal opacities or pleural effusion.  Respiratory infection with which of the following pathogens most likely triggered this patient's worsening symptoms?

Quizplus · Accepted Answer

11ec160b_389d_807c_9249_ad28a7c99c52_MD0001_00 This patient with a history of chronic obstructive pulmonary disease (COPD) has worsened respiratory status (dyspnea, wheezes, pursed breathing) and purulent sputum production, raising strong suspicion for COPD exacerbation. The majority of COPD exacerbations are caused by infections of the upper airway. Infection results in mucus hypersecretion, damage to ciliated cells, cytokine-mediated airway inflammation, and increased respiratory capillary permeability, which can worsen existing airflow obstruction and lead to COPD exacerbation. Most COPD exacerbations are due to common upper respiratory pathogens including Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and rhinovirus. However, patients with severe COPD are also at risk for more opportunistic pathogens such as Pseudomonas aeruginosa. COPD exacerbation can also be induced by exposure to allergens (leading to eosinophilic inflammation of the airway) and environmental pollution. (Choice A) Bordetella pertussis causes whooping cough, which is characterized by a week or two of nonspecific symptoms followed by severe, paroxysmal cough. It is not a typical cause of COPD exacerbation, partially because vaccination against B pertussis makes this pathogen less common. (Choice C) Klebsiella pneumoniae is a common cause of nosocomial pneumonia and may cause community-acquired pneumonia in patients with COPD; it is characterized by "currant-jelly" sputum and early abscess formation. (Choice D) Legionella pneumonia is a common cause of atypical pneumonia and often presents with a few days of gastrointestinal symptoms followed by high fever and pulmonary symptoms. (Choice E) Staphylococcus aureus is a common cause of postinfluenza pneumonia. However, patients with pneumonia have an infiltrate on chest x-ray (unlike this patient). (Choice F) Streptococcus pyogenes is a common cause of acute bacterial pharyngitis but does not usually cause COPD exacerbation. Educational objective: Most chronic obstructive pulmonary disease exacerbations are caused by infection with an upper respiratory pathogen. The leading bacterial cause is Haemophilus influenza and the leading viral cause is rhinovirus. __________ References: COPD exacerbations 2: aetiology (http://www.ncbi.nlm.nih.gov/pubmed/16517585)

A 68-Year-Old Woman Comes to the Emergency Department Due to Cough